Video Duration Calculator
Convert any duration in hours, minutes, and seconds into total seconds, minutes, hours, milliseconds, and frame counts at 24, 30, and 60 fps. Pure math — runs instantly in your browser.
Total duration
- HH:MM:SS
- 0:05:00
- Total seconds
- 300 s
- Total minutes
- 5 min
- Total hours
- 0.0833 h
- Total milliseconds
- 300,000 ms
- Frames @ 24fps
- 7,200
- Frames @ 30fps
- 9,000
- Frames @ 60fps
- 18,000
About Video Duration Calculator
Video Duration Calculator performs video duration calculator as a focused single-page utility. Convert any duration in hours, minutes, and seconds into total seconds, minutes, hours, milliseconds, and frame counts at 24, 30, and 60 fps. Pure math — runs instantly in your browser. Defaults are tuned for the common case so the first run is one click, with every option that matters exposed for the moments you need to fine-tune the result.
Typical users of Video Duration Calculator include teams compressing demo recordings, creators trimming short clips and event organisers sharing highlight footage. The thread connecting all of them is the same: a focused video editing and conversion task that fits cleanly into a browser tab and benefits from a tool with sensible defaults and minimal setup.
Video Duration Calculator parses your file with FFmpeg compiled to WebAssembly entirely inside the browser, applies the options you selected, and returns a download. The processing has no network step, which means a slow or intermittent connection does not slow down the work — once the page is loaded, only your CPU and RAM are involved.
From a technical standpoint, Video Duration Calculator is JavaScript and FFmpeg compiled to WebAssembly running in your tab. The browser is the runtime; the page is the interface. Inputs accepted: MP4, WebM, MOV, MKV, AVI, FLV, and OGV. Maximum input size: 500 MB per run.
The right moment to reach for Video Duration Calculator is when you have a focused video editing and conversion job that fits inside a browser tab. Open the page, drop in the file or paste your input, choose the options that matter, and the tool returns the result.
Workflow tip: Video Duration Calculator pairs well with Video Frame Counter and Video Bitrate Calculator. Other adjacent tools you may find useful are Video File Size Calculator and Video Resolution Checker. Because every tool is a separate page, you can mix and match the steps that match your job. Bookmark the ones you reach for the most.
Video Duration Calculator returns the result as `{name}-edited.{ext}`. If you are running multiple jobs, the output names will not collide as long as the input names differ. You can re-run with different settings as many times as you like; each run produces a fresh file with no caching trickery in between.
A practical note on limits: Video Duration Calculator accepts inputs up to 500 MB per run, and the tool processes one input at a time to keep memory usage predictable. If you ever bump into the ceiling, the cause is the size of the input.
Video Duration Calculator is built around steady iteration on a small set of options rather than feature creep. Every additional setting attracts a slightly different audience, but a long settings panel makes the common case slower for everyone. The current controls reflect what users of the tool actually use.
Some context on why Video Duration Calculator exists in this form: modern File APIs, high-performance JavaScript engines, and well-maintained open-source libraries now make it possible to perform video editing and conversion work entirely in the browser. Video Duration Calculator is built on top of that capability, which is why a single page can host the full pipeline.
A few practical tips that experienced users of Video Duration Calculator pick up over time. First, keep your default browser updated — the engine relies on standard web APIs and newer browser versions are noticeably faster than ones from a few years ago. Second, close other heavy tabs before processing a large input; the engine shares CPU and memory with whatever else is open. Third, if you re-run the same kind of job often, your last-used settings are remembered for the rest of the tab session, so subsequent runs are essentially one click.
For most failure modes, refreshing the page and re-running the job is enough — the engine has no persistent state to corrupt. If the same input fails twice in a row, the input itself is most likely the problem (a truncated file, an unexpected variant of the format, or a stream the engine does not recognise).
Video Duration Calculator produces deterministic output: the same input plus the same options always produces the same result. That predictability matters when the result has to match an upstream specification or be reproducible later.
Video Duration Calculator is intentionally narrow in scope so the common case is fast and the result is predictable. If you ever need a variation it does not cover, browse the rest of the catalog — there is a good chance an adjacent tool already exists, and switching between tools is just a matter of opening another tab.
How it works
- 1Reach the Video Duration Calculator page in your browser to begin.
- 2Select the MP4, WebM, MOV, MKV, AVI, FLV, and OGV file you want to process — drag-and-drop and the file picker both work.
- 3Tweak the controls if the defaults are not quite right for your input. The options are kept short and labelled in plain language.
- 4Trigger processing. FFmpeg compiled to WebAssembly reads your input, applies the transformation, and writes the result back into the page.
- 5Save the output (`{name}-edited.{ext}`) when it is ready.
- 6Run additional jobs as needed. The same controls and defaults apply on every run.
Common use cases
- Convert a phone-recorded clip into a web-friendly MP4 using Video Duration Calculator.
- Extract a still frame from a video for use as a thumbnail.
- Stitch several short clips into a single uploadable video.
- Strip the audio track from a screencast for a silent loop.
- Compress a demo video small enough to attach to an email.
- Re-encode a clip so it plays on an older device without stuttering.
- Trim the silent intro from a screen recording before sharing it.
- Cut a long meeting recording down to the relevant five minutes.
Frequently asked questions
How does the calculator work?
Pure JavaScript math runs in your browser. Enter hours, minutes, and seconds and instantly get the duration in every common unit and frame count at standard frame rates.
Why use this tool?
Quickly answer questions like "how many frames is a 5-minute video at 24 fps?" or "how many seconds is 1h 23m 45s?". Useful for editing budgets, subtitle timing, animation scoping, and storage calculations.
Why is this not slower in browser?
Unlike video transcoding, this is pure arithmetic — there is no FFmpeg WebAssembly involved. Results are instant and identical to any server-side tool.
How are frame counts calculated?
Frames = seconds × fps, rounded to the nearest integer. We show 24 fps (cinematic), 30 fps (web standard), and 60 fps (smooth) — the three most common rates.
Can I enter fractional seconds?
Yes — the seconds field accepts any value. For sub-second precision, type a decimal like 30.5 directly into the seconds box.
What about drop-frame timecode (NTSC 29.97)?
This tool assumes integer frame rates. For broadcast NTSC drop-frame math (29.97 fps with skipped frames), use a dedicated SMPTE timecode calculator.
How do I go the other way (seconds → HH:MM:SS)?
Set hours and minutes to 0 and enter your total seconds. The result panel shows the equivalent HH:MM:SS at the top.
Is anything logged?
No. The calculator runs entirely in your browser tab. Nothing is transmitted, stored, or logged.
Does Video Duration Calculator ask for any browser permissions?
Video Duration Calculator only needs the standard web platform — file picker access for the inputs you choose to load, and optionally clipboard access if you copy the result rather than downloading it. There is no microphone, camera, geolocation or background-permission request, because none of those are needed for the work the tool does. Some browsers prompt the first time WebAssembly is compiled; that is a normal one-time event, not specific to Favtoo.
Is there a programmatic version of Video Duration Calculator?
Video Duration Calculator is a browser-only tool by design and does not expose a hosted API. The reason is the same as the privacy story: there is no Favtoo backend doing the work, so there is no service to call. If you need to script the same transformation, the underlying engine (FFmpeg compiled to WebAssembly) is open-source and can be used directly from your own code.
Can I trust the output of Video Duration Calculator for important work?
Video Duration Calculator is built on FFmpeg compiled to WebAssembly, which is the same class of engine used by professional video editing and conversion pipelines. For deterministic operations, the output is byte-identical to what an equivalent CLI run would produce; for operations involving a codec or a model, the result is well within the range of what comparable tools generate. If you have a specific reference output you need to match, run a small test job first to confirm the configuration produces what you expect.
Is Video Duration Calculator lossless?
Video Duration Calculator is built to preserve quality wherever the underlying video format allows it. Operations that are mathematically lossless (e.g. structural transformations, lossless re-encoding) round-trip with no perceptible change. Operations that involve a lossy codec inevitably introduce small artefacts at the byte level, but the defaults aim at the sweet spot where output looks or sounds the same to a normal viewer or listener while still being meaningfully smaller or faster than the input.
Does Video Duration Calculator support batch processing?
Video Duration Calculator processes one input at a time by design — it keeps memory usage predictable on lower-end devices and makes results easier to verify. To handle a folder, run the tool once per file; the page stays loaded between runs and remembers your last-used settings, so the second run is essentially instant.
Why use Video Duration Calculator instead of a paid online tool?
Desktop apps usually have more advanced features but require installation, maintenance and (often) a licence. Paid online tools are convenient but route your file through their servers and gate downloads behind accounts. Video Duration Calculator sits in between: free, instant, and private, but intentionally narrow in scope. For one-off jobs and the common video editing and conversion operations, it is usually the lowest-friction choice; for highly specialised work, a dedicated app is still the right answer.
Is the source for Video Duration Calculator available?
Video Duration Calculator is a static page running an open-source engine in your browser, so a typical corporate firewall does not get in the way as long as it allows JavaScript and WebAssembly to load from Favtoo. For teams that need to host it themselves on an internal network, the underlying engine (FFmpeg compiled to WebAssembly) is open-source and can be packaged into a private build with the same behaviour. Reach out via the Contact page if that is something you are exploring.
What should I do if Video Duration Calculator fails on my file?
Failures usually fall into one of three buckets: the input is in an unsupported format, the input is over the size cap, or the input is structurally malformed (a truncated download, a partial export, or a stream the engine does not recognise). The first two are easy to confirm — check that your file is one of MP4, WebM, MOV, MKV, AVI, FLV, and OGV and that it is below 500 MB. For the third, opening the file in its native viewer first is the fastest way to confirm the source is intact.
How accessible is the Video Duration Calculator interface?
Video Duration Calculator uses native HTML controls wherever possible, which means keyboard navigation, focus rings, and screen-reader labels work the way the platform expects. The drop zone accepts files via the keyboard-accessible file picker as well as drag-and-drop, and result downloads use standard browser download flows. If you spot an accessibility gap, Favtoo treats it as a bug worth fixing.