Calculators

Quadratic Equation Solver

Solve ax² + bx + c = 0 with the quadratic formula, discriminant, and complex roots when needed.

Linear Equation Solver

Solve ax + b = 0 for x, including the identity and no-solution cases.

Ratio Calculator

Given a : b = c : x, compute the missing fourth proportional x from three known values.

Proportion Calculator

Solve a/b = c/d for whichever variable is unknown using cross-multiplication.

Logarithm Calculator

Compute log base b of x for positive x and valid bases using the change-of-base formula.

Natural Log Calculator

Compute the natural logarithm ln(x) for positive x in one click.

System of Equations Solver

Solve a 2×2 linear system a₁x+b₁y=c₁, a₂x+b₂y=c₂ using Cramer’s rule in your browser.

Polynomial Root Finder

Find real roots of quadratic or cubic polynomials using the quadratic formula and Cardano’s method for cubics.

Linear Inequality Solver

Solve one-step linear inequalities of the form ax + b compared to c with correct flip when a < 0.

Variation Calculator

Compute y for direct variation y = kx or inverse variation y = k/x given k and x.

Sequence Calculator

Get the nth term and partial sum of an arithmetic or geometric sequence from a₁, difference or ratio, and n.

Series Sum Calculator

Sum the first n terms of an arithmetic or geometric series from the first term and common difference or ratio.

Binomial Theorem Calculator

Expand (a + b)ⁿ numerically for integer n up to 20 and list binomial-weighted terms.

Antilog Calculator

Raise a base to a power: antilog base b of x is bˣ, default base 10.

2×2 Matrix Calculator

Determinant, transpose, addition, and multiplication for two 2×2 matrices entered by elements.

Matrix Determinant Calculator

Compute the determinant of a 2×2 or 3×3 matrix from its entries.

2×2 Matrix Inverse Calculator

Invert a 2×2 matrix when the determinant is non-zero; shows inverse rows and det(A).

2×2 Matrix Transpose Calculator

Swap rows and columns of a 2×2 matrix to get its transpose Aᵀ.

2D Vector Calculator

Add, subtract, dot product, or magnitude for 2D vectors from their components.

Complex Number Calculator

Add, subtract, multiply, or divide two complex numbers given real and imaginary parts.

Concrete Volume Calculator

Estimate concrete volume in cubic yards from slab length, width, and depth in feet and inches.

Brick Calculator

Estimate brick count from wall area and brick size class using common bricks-per-square-foot rules.

Paint Calculator

Estimate gallons from room dimensions using about 350 square feet per gallon and your coat count.

Flooring Calculator

Compute net square footage and add a waste percentage for flooring orders.

Tile Calculator

Estimate how many tiles are needed from floor area and nominal tile size in inches.

Wallpaper Roll Calculator

Estimate rolls from perimeter, wall height, and roll width assuming a standard roll length.

Gravel / Sand Ton Calculator

Convert a box of length, width, and depth in feet to cubic yards and a rough tons estimate.

Roofing Squares Calculator

Estimate roof surface area from footprint and pitch, then express area in roofing squares.

Board Feet Calculator

Compute board feet from nominal thickness and width in inches and length in feet.

Square Footage Calculator

Convert a rectangle in feet to square feet, square meters, and acres.

Fence Post & Rail Estimator

Estimate posts from fence line length and spacing, plus rails assuming three rails per segment.

Pool Volume Calculator (Gallons)

Estimate gallons for rectangle, round, or oval pools from dimensions and average depth in feet.

Stair Calculator

Estimate the number of steps from total rise and target riser height, plus a tread suggestion.

Beam Load Calculator (Uniform)

Estimate maximum bending moment for a simply supported beam with uniform load per foot.

Property Tax Calculator

Multiply assessed home value by a tax rate percentage to estimate annual property tax.

Rent Affordability Calculator

Estimate maximum affordable rent using a 28% of gross income rule minus monthly debt payments.

Home Equity Calculator

Subtract mortgage balance from home value to show equity dollars and percent of value.

Loan-to-Value (LTV) Calculator

Compute LTV as loan amount divided by property value times 100.

Date Difference Calculator

Days, weeks, months, and years between two dates.

Date Add and Subtract

Add or subtract days, weeks, months, or years from a start date.

Day of Week Calculator

Weekday name for any ISO calendar date.

Days Until Calculator

Whole days from today to a target date in UTC.

Business Days Calculator

Count Monday–Friday weekdays between two dates.

Work Hours Calculator

Total paid hours between clock times minus break minutes.

Unix Timestamp Converter

Unix seconds to ISO date-time and back bidirectionally.

Countdown Timer

Days, hours, minutes, and seconds snapshot to a date.

Time Duration Calculator

Duration between two clock times with hours, minutes, seconds.

ISO Week Number Calculator

ISO-8601 week label for a given date.

Leap Year Checker

Gregorian leap test and next leap year lookup.

Days in Month Calculator

How many days a month has for a chosen year.

Time to Decimal Hours

HH:MM:SS clock time to decimal hours bidirectionally.

Decimal Hours to Time

Decimal hours to HH:MM:SS and reverse bidirectionally.

GPA Calculator (4.0 Scale)

Compute weighted GPA from letter grades with credits like A:3, B+:4 on a 4.0 scale.

Weighted Grade Average Calculator

Compute a weighted average from parallel lists of scores and weights, with a typical letter label.

Exam Score Calculator

Turn correct answers and total questions into a percent score and a simple letter grade.

CGPA to Percentage Converter

Multiply CGPA by 9.5, 10, or a custom multiplier to approximate a percentage (institutions vary).

Percentage to CGPA Converter

Divide percentage by 9.5, 10, or a custom divisor to approximate CGPA (illustrative only).

Test Score Percentage Calculator

Convert obtained marks and total marks into a percentage and a simple letter grade.

Class Rank Percentile Calculator

Convert your rank and class size into an approximate percentile-rank style summary.

Study Hours Planner

Spread total study hours across days until an exam date from topics and hours per topic.

Essay Word to Pages Estimator

Estimate page count from word count, font size, and line spacing using common words-per-page heuristics.

Fuel Cost Calculator

Multiply trip distance by fuel price per liter divided by kilometers per liter for total fuel cost.

MPG Calculator

Divide miles driven by gallons used to get miles per gallon.

Electricity Cost Calculator

Estimate energy cost from device watts, hours per day, billing days, and price per kilowatt-hour.

Solar Panel Count Estimator

Roughly divide monthly kWh by estimated monthly yield per panel from sun hours and panel wattage.

Download Time Calculator

Estimate transfer time from file size in megabytes and download speed in megabits per second.

File Download Time (MB or GB)

Pick MB or GB for file size and enter Mbps to estimate ideal download duration in seconds.

Bandwidth Calculator

Solve for required Mbps to move a file in megabytes within a time budget in seconds.

Screen PPI Calculator

Compute pixels per inch from horizontal and vertical resolution and diagonal size in inches.

Aspect Ratio Calculator

Simplify width:height to smallest integers and guess a common widescreen name when it matches.

Image File Size Estimator

Rough uncompressed bytes from pixels and bit depth, then scale by a simple compression profile.

Cooking Measurement Converter

Convert common kitchen volumes among cups, tablespoons, teaspoons, fluid ounces, milliliters, and liters.

Recipe Scaler

Scale serving counts and multiply leading numeric amounts on each ingredient line by the ratio.

Baking Unit Converter

Convert flour, sugar, or butter among cups, grams, and ounces using typical cup weights.

Alcohol Units Calculator

Estimate UK-style alcohol units from drink volume in milliliters and ABV percent.

Caffeine Intake Estimator

Multiply typical milligrams per serving by the number of coffees, teas, or energy drinks.

Lottery Odds Calculator

Show one-in-X odds for combinations from main pool size and picks, with optional bonus combinations.

Dice Sum Probability

Compute exact probability for a target sum with fair six-sided dice using dynamic programming counts.

Card Draw Probability (Hypergeometric)

Compute P(X = k) for drawing without replacement from a deck with marked successes.

Simple Interest Calculator

Compute simple interest and total amount from principal, annual rate percent, and time in years.

Compound Interest Calculator

Project maturity with A = P(1 + r/n)^(nt) for annual percent rate, years, and compounding frequency.

Mortgage Calculator

Estimate monthly mortgage payment and total interest from loan amount, annual rate, and term in years.

Car Loan Calculator

Find an auto loan monthly payment from vehicle price, down payment, annual rate, and term in months.

Personal Loan Calculator

Compute monthly payment, total repaid, and interest for a fixed-rate personal loan over months.

Home Loan Calculator

Derive loan amount from home price and down percent, then monthly payment and total interest over years.

Credit Card Payoff Calculator

Simulate months to zero balance and total interest paid from balance, APR, and a fixed monthly payment.

Savings Calculator

Project future value with an initial deposit, monthly contributions, annual rate, and horizon in years.

FD Calculator (Quarterly Compounding)

Estimate fixed deposit maturity with principal, annual rate, and tenure using quarterly compounding.

RD Calculator (Recurring Deposit)

Approximate recurring deposit maturity from monthly installment, annual rate, and tenure in months.

PPF Calculator (Simplified)

Rough maturity from yearly deposits with a default 7.1% rate and 15-year tenure using simplified annual compounding.

SIP Calculator

Estimate mutual-fund-style SIP future value from monthly investment, expected annual return, and years.

Lumpsum Investment Calculator

Compound a single lump sum at a constant annual return percentage over a whole-number of years.

ROI Calculator

Compute return on investment percent and optional annualized ROI when you also enter years held.

NPV Calculator

Discount comma-separated yearly cash flows after an initial investment using one annual discount rate.

IRR Calculator (Newton)

Estimate internal rate of return with Newton–Raphson from a negative initial cash flow and future flows.

Break-Even Calculator

Divide fixed costs by per-unit contribution margin to get break-even units sold.

Profit / Loss Calculator

Subtract cost from selling price to see profit or loss amount and percent of cost.

Markup Calculator

Apply a markup percent to cost to get selling price and gross profit in one step.

GST Calculator (CGST / SGST)

Split Indian-style GST into equal CGST and SGST halves plus total tax and invoice total.

Inflation Calculator

Show future nominal value and today’s purchasing power equivalent using compound inflation.

Retirement Savings Calculator

Project account balance at retirement from current savings, monthly contributions, and return rate.

Net Worth Calculator

Sum comma-separated assets and liabilities lists to compute total assets, debts, and net worth.

50/30/20 Budget Calculator

Split monthly income into 50% needs, 30% wants, and 20% savings or debt paydown using the rule of thumb.

Split Bill Calculator

Add tip percent to the bill total and divide evenly across the number of people dining or sharing.

Salary to Hourly Calculator

Divide annual salary by default 40 hours per week and 52 weeks to get an equivalent hourly rate.

Hourly to Salary Calculator

Multiply hourly rate by hours per week and weeks per year for an implied annual salary.

Paycheck Calculator

Subtract a flat tax percent and other deductions from gross pay to approximate net pay.

Freelancer Hourly Rate Calculator

Spread desired annual income plus expenses over billable hours after weeks off to get a minimum hourly rate.

Area Calculator

Find area for triangle, rectangle, circle, or trapezoid using the dimensions you provide.

Perimeter Calculator

Perimeter for triangle, rectangle, circle, or trapezoid using sides, radius, or leg lengths.

Volume Calculator

Volumes for sphere, cube, cylinder, and cone from radius, edge, or height.

Surface Area Calculator

Surface area for sphere, cube, cylinder, or cone including lateral parts where applicable.

Circle Calculator

From radius or diameter, get area, circumference, and the other linear measure.

Triangle Calculator

Area from base and height, perimeter from three sides, and triangle type classification.

Rectangle Calculator

Area, perimeter, and diagonal from length and width.

Square Calculator

Area, perimeter, and diagonal from one side length.

Trapezoid Calculator

Area from parallel bases and height; perimeter from bases and both legs.

Parallelogram Calculator

Area as base×height and perimeter as 2(base + adjacent side).

Regular Polygon Calculator

Area, perimeter, and interior angle for a regular polygon from side count and side length.

Ellipse Calculator

Area and Ramanujan-style circumference approximation from semi-major and semi-minor axes.

Cylinder Calculator

Volume, lateral surface area, and total surface area from radius and height.

Sphere Calculator

Volume and surface area of a sphere from its radius.

Cone Calculator

Volume, slant height, and surface area of a right circular cone.

Cube Calculator

Volume, surface area, and space diagonal from edge length.

Square Pyramid Calculator

Volume (base²×h/3) and surface area for a right square pyramid from base edge and height.

Pythagorean Theorem Calculator

Find hypotenuse from two legs or a missing leg from one leg and the hypotenuse.

Distance Between Two Points

Euclidean distance in the plane from coordinates (x₁,y₁) and (x₂,y₂).

Midpoint Calculator

Midpoint of a segment from endpoints (x₁,y₁) and (x₂,y₂).

Slope Calculator

Slope between two points and angle of inclination in degrees (except vertical lines).

Angle & Trig Calculator

Convert degrees and radians and show sin, cos, and tan for the angle.

BMR Calculator (Mifflin–St Jeor)

Estimate basal metabolic rate in kilocalories per day from weight, height, age, and sex.

TDEE Calculator

Multiply Mifflin–St Jeor BMR by an activity factor from sedentary through very active levels.

Calorie Target Calculator

Start from TDEE and adjust by −500, 0, or +500 kcal for lose, maintain, or gain goal presets.

Calorie Burn Calculator (MET)

Multiply MET by body weight and duration to approximate kilocalories burned for common activities.

Ideal Body Weight Calculator (Devine)

Apply the Devine formula from height in centimeters and gender for a classic reference weight in kilograms.

Body Fat Calculator (U.S. Navy)

Estimate body fat percent from neck, waist, height, and hip (women) using the U.S. Navy circumference method.

Waist-to-Hip Ratio Calculator

Divide waist by hip in centimeters and compare to WHO-style high-level risk bands for men and women.

Daily Water Intake Calculator

Scale liters per day from body weight and a coarse activity bucket using milliliters-per-kilogram heuristics.

Protein Intake Calculator

Multiply weight in kilograms by grams-per-kilogram tied to sedentary through very active presets.

Macro Calculator (Calorie Split)

Turn daily calories into protein, carbohydrate, and fat grams for balanced, low-carb, or high-protein presets.

Heart Rate Zone Calculator

Use the 220 minus age estimate for max heart rate and show three coarse training zone bpm ranges.

VO₂ Max Calculator (Cooper)

Apply the Cooper test linear formula to twelve-minute run distance in meters for an estimated VO₂ max.

Pace Calculator

Compute pace per km or mile from distance and time.

Steps to Distance Calculator

Convert steps and stride length into kilometers and miles.

Sleep Cycle Bedtime Calculator

Suggested bedtimes from wake time using 90-minute cycles.

Ovulation Estimator

Rough fertile-window estimate from last period and cycle length.

Pregnancy Due Date Calculator

Classic due date from first day of last period plus 280 days.

Baby Age Calculator

Age in years, months, and days from a birth date.

Child Height Predictor

Mid-parental adult height estimate from parent heights.

Basic Calculator

Add, subtract, multiply, divide, or take the remainder of two numbers in your browser.

Scientific Calculator

Evaluate expressions with trig, log, powers, parentheses, pi, and e using a safe parser (no eval).

Fraction Calculator

Add, subtract, multiply, or divide two fractions and get a simplified result as a fraction and decimal.

Decimal to Fraction Converter

Convert decimals to simplified fractions or fractions to decimals with one bidirectional field.

Fraction to Decimal Converter

Turn fractions into decimals or decimals into simplified fractions using bidirectional conversion.

Square Root Calculator

Compute the square root of a non-negative number and see whether it is a perfect square.

Cube Root Calculator

Compute the cube root of any real number, including negatives, in one step.

Power Calculator

Raise a base to an exponent and see the numeric result for real powers.

Factorial Calculator

Compute n factorial for integers from 0 through 170 using exact big-integer arithmetic.

Modulo Calculator

Find the remainder after dividing one number by another (the modulo operation).

Absolute Value Calculator

Compute the absolute value |x| of any real number you enter.

LCM Calculator

Find the least common multiple of two integers using the GCD relationship.

GCD Calculator

Find the greatest common divisor of two integers with the Euclidean algorithm.

Prime Number Checker

Test whether a non-negative integer is prime and list helpful factors when it is composite.

Prime Factorization Calculator

Decompose an integer into its prime factors with compact exponent notation.

Random Number Generator

Generate up to 100 cryptographically random integers in an inclusive min–max range.

Number Rounding Calculator

Round a number to chosen decimal places and compare round, ceil, and floor side by side.

Significant Figures Calculator

Round a number to between one and eight significant figures for lab-style reporting.

Scientific Notation Converter

Convert ordinary numbers to scientific notation and parse scientific strings back to standard form.

Binary to Decimal Converter

Binary integers to decimal and back bidirectionally.

Decimal to Binary Converter

Decimal integers to binary text and reverse.

Hex to Decimal Converter

Hexadecimal integers to decimal and back.

Decimal to Hex Converter

Decimal integers to uppercase hex and reverse.

Octal to Decimal Converter

octal ↔ decimal integers

Decimal to Octal Converter

decimal ↔ octal integers

Binary to Hex Converter

binary ↔ hexadecimal

Hex to Binary Converter

hexadecimal ↔ binary

Binary to Octal Converter

binary ↔ octal

Octal to Binary Converter

octal ↔ binary

Number Base Converter

parse number colon base to decimal

Roman Numeral Converter

Roman numerals ↔ decimal 1–3999

Number to Words Converter

integer digits ↔ English words

Words to Number Converter

English words ↔ integer

BCD Calculator

decimal ↔ packed BCD nibbles

Ohm's Law Calculator

solve V I R with any two

Resistor Color Code Calculator

four band resistance

Capacitor Energy Calculator

E equals one half C V squared

Inductor Energy Calculator

E equals one half L I squared

Wavelength Frequency Calculator

c equals lambda f vacuum

Decibel Power Calculator

ten log10 P2 over P1

Voltage Divider Calculator

Vout unloaded resistor divider

LED Resistor Calculator

series resistor from V I

Power Factor Calculator

PF equals P over S

Electric Charge Calculator

Q equals I times t

Molarity Calculator

M equals n over V

Dilution Calculator

C1V1 equals C2V2

pH Calculator

pH from hydrogen ion molarity

Molecular Weight Calculator

simple element formula weight

Ideal Gas Law Calculator

PV equals nRT SI R 8.314

Kinetic Energy Calculator

one half m v squared

Potential Energy Calculator

m g h near Earth

Velocity Calculator

v equals d over t plus km/h mph

Acceleration Calculator

Find average acceleration from velocity change and elapsed time using a = Δv/Δt.

Force Calculator (F = ma)

Compute force in newtons from mass in kilograms and acceleration in m/s².

Momentum Calculator

Calculate linear momentum p = mv from mass and velocity in SI units.

Torque Calculator

Find torque τ = F d sin(θ) with force, lever arm distance, and angle in degrees.

Pressure Calculator

Compute pressure P = F/A from force in newtons and area in square meters.

Density Calculator

Find density ρ = m/V from mass and volume in kilograms and cubic meters.

Buoyancy Calculator

Estimate buoyant force Fb = ρ V g using fluid density, submerged volume, and gravity.

Heat Transfer Calculator (Q = mcΔT)

Compute heat energy Q = m c ΔT for a temperature change using specific heat.

Thermal Expansion Calculator

Estimate length change ΔL = α L₀ ΔT for linear thermal expansion.

Hooke’s Law Calculator

Compute spring force F = k x from spring constant and displacement.

Mean Median Mode Calculator

Compute mean, median, and mode(s) from a comma- or space-separated list of numbers.

Standard Deviation Calculator

Sample and population standard deviation and variance from a number list.

Variance Calculator

Population and sample variance from a comma-separated list of numbers.

Range Calculator

Minimum, maximum, and range from a list of numbers.

Percentile Calculator

Linear-interpolated percentile from a sorted view of your numeric list.

Z-Score Calculator

Standardize a value with z = (x − μ) / σ for a given mean and standard deviation.

Confidence Interval Calculator

Normal-approximate two-sided CI for a mean using z for 90%, 95%, or 99%.

Sample Size Calculator

Approximate sample size for estimating a proportion at a given margin and confidence.

Probability Calculator

Classical probability as favorable outcomes divided by total outcomes.

Permutation Calculator nPr

Permutations nPr = n!/(n−r)! for non-negative integers with r ≤ n.

Combination Calculator nCr

Combinations nCr = n!/(r!(n−r)!) for non-negative integers with r ≤ n.

Binomial Distribution PMF

Probability P(X = k) for Binomial(n, p) using the binomial formula in log form for stability.

Normal Distribution Calculator

z-score and approximate P(X ≤ x) for a normal with mean μ and standard deviation σ.

Poisson Distribution PMF

Probability P(X = k) for Poisson(λ) using λ and integer k.

Correlation Coefficient Calculator

Compute Pearson’s r from two comma-separated lists of paired x and y values in your browser.

Linear Regression Calculator

Fit a least-squares line to paired x and y data and read slope, intercept, and R².

Chi-Square Calculator

Compare observed and expected frequency lists and compute the chi-square statistic and degrees of freedom.

Two-Sample t-Test Calculator

Run Welch’s two-sample t-test from two comma-separated samples and compare p-value to your alpha.

P-Value from z-Score Calculator

Convert a standard normal z-score to two-tailed and one-tailed p-values using a normal approximation.

Weighted Average Calculator

Combine two matching lists of values and weights to compute a weighted arithmetic mean.

Simple Moving Average Calculator

Enter a series and a window size to see the SMA sequence and the latest smoothed value.

Geometric Mean Calculator

Compute the geometric mean of positive numbers from a single comma-separated list.

Harmonic Mean Calculator

Calculate the harmonic mean for rates and ratios from a comma-separated list of non-zero values.

Length Unit Converter

km m cm mm mi yd ft in

Weight Unit Converter

kg g mg lb oz stone

Temperature Converter

Celsius Fahrenheit Kelvin

Area Unit Converter

sq m sq ft sq yd acre hectare

Volume Unit Converter

L mL gal qt pt cup fl-oz

Speed Unit Converter

km/h mph m/s knots

Time Unit Converter

seconds through weeks

Pressure Unit Converter

Pa kPa bar psi atm

Energy Unit Converter

J kJ cal kcal kWh BTU

Power Unit Converter

W kW hp BTU/h

Data Storage Converter

B KB MB GB TB PB binary

Data Transfer Speed Converter

bps Kbps Mbps Gbps decimal

Frequency Unit Converter

Hz kHz MHz GHz

Fuel Efficiency Converter

MPG L/100km km/L US MPG

Angle Converter

deg rad grad together

Torque Converter

Nm ft-lb kgf-m

Density Converter

kg/m3 g/cm3 lb/ft3

Force Converter

N kN lbf kgf dyn

Illuminance Converter

lux and foot-candles

Shoe Size Converter

US UK EU approximate

Clothing Size Converter

XS–XXL US UK EU