Pad String — Left or Right
Left-pad or right-pad a string with a chosen character to a target length from presets.
How it works
- 1Paste or type your text in the input field
- 2Click "Pad String" — processing happens in your browser
- 3Copy the result or download as a text file
What to do next
About Pad String
Pad String is the kind of utility you bookmark and reach for when you need it. Left-pad or right-pad a string with a chosen character to a target length from presets. It loads quickly, works on any modern browser, and produces a result you can download or copy in a single click.
Anyone who works with text processing on a casual basis — writers cleaning copy before publishing, editors comparing manuscript drafts, marketers polishing product copy — finds Pad String a quick way to get the result. The page loads in under a second, the controls are visible from a single screen, and the result downloads or copies in one click.
Pad String performs the transformation entirely inside the JavaScript runtime. Your file lives in the tab's memory while the engine works on it; the result lives in the tab's memory until the browser triggers the download. Both are released when the tab closes, the way every browser tab releases its memory.
Pad String is implemented on top of standard browser APIs. Inputs are read from the file picker or drop zone, decoded in the browser, processed, and re-encoded into the output format. Files up to 0 MB are well within the comfort zone of any modern browser.
Reach for Pad String when you need a predictable result on a single file. The page works on the first visit, the controls are visible without a menu, and the output is delivered the moment the engine finishes.
Pad String fits naturally next to several adjacent tools. Common companions include Truncate String, Extract Numbers, JSON to Key:Value Lines, and Key:Value Lines to JSON — combine them when the job needs more than one transformation. After running Pad String, many users move on to Truncate String and JSON to Key:Value Lines. Each tool is a separate page so you can compose the exact pipeline you need.
The output handed back by Pad String is the output file. If you would prefer to keep the result in the browser instead of downloading it, you can copy it from the result panel and paste it directly into another tab — useful when the next tool in your workflow expects pasted text rather than a file.
The hard constraints are easy to remember. Maximum input: 0 MB. Multiple files per run: no — one input at a time, by design, to keep results predictable. The same controls apply on every run.
Pad String 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 background on the design choices behind Pad String: every option you see on the page is there because a real workflow needs it, and every option that is not shown has been deliberately omitted to keep the common case fast. The bias is toward minimal-but-complete.
Useful patterns when working with Pad String: keep the input file open in another tab so you can compare against the result; give the output file a descriptive name when saving so you can find it later (the default name is sensible but generic); and treat each run as independent — the tool has no concept of "history", which means you cannot accidentally pollute one job with leftovers from another.
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).
If you also use a command-line tool for pad string, Pad String is a convenient alternative for the times you are on a different machine or helping someone who is not comfortable in a terminal. The output is a standard file in the format documented above.
Open the workspace above to start using Pad String. The engine loads on the first interaction so the page itself stays light, and once the tool is warm it processes subsequent jobs quickly. The moment the page is interactive, the tool is ready to do real work on your file.
How it works
- 1Open the Pad String workspace above. The interface is a single page, so there is nothing to navigate.
- 2Add your text input by dropping it onto the page or browsing for it.
- 3Tweak the controls if the defaults are not quite right for your input. The options are kept short and labelled in plain language.
- 4Click to start the job. The engine (standard browser APIs) processes the input in the page; you can watch the progress indicator until it completes.
- 5Download the result. The file is generated in your browser and saved through your normal download flow.
- 6Re-run with different settings as often as you want. Each run produces a fresh output and the original file on disk is never modified.
Common use cases
- Translate plain text into Markdown for a static-site post using Pad String.
- Convert a column of names into a comma-separated list for a script.
- Reformat a JSON blob copied from a log into something readable.
- Find and replace dozens of variants of a phrase in one pass.
- Diff two drafts of a document side by side.
- Re-case a title from ALL CAPS to Title Case.
- Strip messy formatting out of copy pasted from a PDF.
- Count the words in a draft to check it fits a brief.
FAQ
Longer than target?
Strings already at or beyond the target length are returned unchanged.
Multi-character pad?
Only the first character of the selected pad token is repeated.
Unicode width?
JavaScript string length counts code units, not monospace display width.
Local only?
Yes — nothing is uploaded.
Binary data?
Treat as text; arbitrary bytes should use proper binary tools instead.
Sign alignment?
Pad numbers as strings; numeric parsing is not applied here.
Does Pad String match what professional tools produce?
Pad String is built on standard browser APIs, which is the same class of engine used by professional text processing 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.
How long does Favtoo retain my data after using Pad String?
Favtoo keeps no copy of your file because Favtoo never receives your file. Pad String runs entirely in your browser, the input is held only in your tab's memory, and closing the tab discards it. There is no opt-in cloud history, no "recent jobs" panel synced to an account, and no server-side retention to configure — the architecture simply has nowhere for your file to be stored.
Do I need a specific browser to use Pad String?
Pad String works in any modern browser released in the last few years — Chrome, Edge, Firefox, Safari, Brave, Arc and the major Chromium derivatives are all supported. The underlying engine relies on widely-supported web APIs, so there is nothing exotic to install. If you are on a very old browser version and the tool fails to load, updating to the latest release of your preferred browser is the only fix needed.
What does Pad String do that command-line tools do not?
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. Pad String sits in between: free, instant, and private, but intentionally narrow in scope. For one-off jobs and the common text processing operations, it is usually the lowest-friction choice; for highly specialised work, a dedicated app is still the right answer.
Why did Pad String reject my input?
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 in a supported format and that it is below 0 MB. For the third, opening the file in its native viewer first is the fastest way to confirm the source is intact.
Are there any usage limits on Pad String?
Inputs are capped at 0 MB per file, which keeps memory usage stable across phones, tablets and older laptops. You can run Pad String as often as you need; every run produces a full-quality result.
How do I run Pad String over a folder of files?
Pad String 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.
Will I notice a difference in the output from Pad String?
Pad String is built to preserve quality wherever the underlying text 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.