What it does
Everything below works in the editor above, free and without an account. The engine is JavaScript running in your browser, so this list is also here for search engines, which cannot run it.
Editing
- Edit subtitle text and timecodes directly in the cue list
- Nudge any cue 100 milliseconds earlier or later
- Split one cue into two, or merge a cue with the one after it
- Insert and delete cues — numbering is always recalculated
- Select multiple cues and delete them together
- Find and replace across the whole file, plain text or regular expressions
- One-click cleanups: remove (parentheticals), [bracketed annotations], lyric lines, or all markup
- Undo and redo every change, including batch and timing operations
Readability checks, live
- Reading speed in characters per second, recalculated as you type or retime
- Per-line character counts against the 42-character limit
- Warnings for three-line cues, over-long and over-short durations
- Overlap and minimum-gap detection between consecutive cues
- A file-level report grouping every warning with counts
- Netflix and BBC threshold profiles
Fixes
- Smart re-break: over-length lines re-broken at the best grammatical point
- Batch re-break every over-length line in the file at once
- Extend a fast cue into the gap after it, never into the next cue
- Trim out-times to enforce a minimum gap between cues
Timing
- Shift every cue by a fixed offset
- Shift from one cue onward, leaving earlier cues alone
- Two-point drift correction — anchor an early and a late cue, stretch everything between
- Frame-rate conversion between 23.976, 24, 25, 29.97, 30, 50, 59.94 and 60
Files
- Opens .srt and .vtt, by drag-and-drop, file picker, or pasted text
- Opens several files at once
- Repairs malformed files on import and tells you exactly what it changed
- Exports .srt, .vtt, and plain text with cues merged into readable paragraphs
What the warnings mean
The editor checks your file against the thresholds professional subtitlers work to. They are conventions, not rules: a warning tells you something and never stops you, and different broadcasters use different numbers — Netflix keeps lines to 42 characters, the BBC to 37. Every threshold below is adjustable in the editor under Limits, so you can check against the standard you actually work to.
Netflix caps adult programmes at 20 characters per second and children’s at 17. The BBC works in words per minute instead — 160 to 180 — which lands in a similar place. Above it, viewers are still reading when the subtitle disappears.
Netflix keeps lines to 42 characters; the BBC to 37, because Teletext gives 40 bytes a line and at least three go to control codes. Longer lines get cut off, or shrunk to fit, by players that have to make them work on a small screen.
Both Netflix and the BBC recommend a maximum of two lines for landscape video. A third covers too much of the picture and pulls the eye away from the action it is meant to support. The BBC allows three for vertical 9:16 video, where there is room.
Netflix’s figures: at least five-sixths of a second, at most seven. Shorter does not register even when the text is short; longer and people start re-reading it. The BBC sets no fixed pair, aiming instead for about 0.3 seconds per word.
The one threshold where the guidelines differ. Netflix requires at least two frames between cues at any frame rate, and says a gap should be either two frames or half a second or more — never in between. The BBC guidelines set no frame gap at all; their only gap rule is that a pause in speech should be at least a second. We warn below 80ms, two frames at 25fps, and treat it as advice rather than a defect.
Where these numbers come from. The character limit, reading speeds, line count and durations are quoted from the Netflix English Timed Text Style Guide, its General Requirements and the Subtitle Timing Guidelines (updated 4 July 2025), and from the BBC Subtitle Guidelines (v1.2.5, March 2026). All read directly on 10 September 2026.
What is ours rather than theirs. Both bodies publish a single limit, not a warning zone, so the amber “approaching the limit” band is our own judgement. The BBC states reading speed in words per minute — 160–180 wpm — so the characters-per-second figure in the BBC profile is our conversion, not their number. And because a subtitle file carries no frame rate, the two-frame gap is stored as 80 milliseconds, which is two frames at 25fps and sits inside the 67–83ms the rule spans across common frame rates.
Why nothing is uploaded
When you open a file here, the browser reads it from your disk into memory in this tab. Every edit, check, and fix runs on that copy, in your browser, using JavaScript that was delivered when the page loaded. When you download the result, the browser writes a new file from what is in memory. At no point does the subtitle text travel over the network, because there is nothing on our side to receive it — this feature has no upload endpoint.
You can check this rather than take our word for it: load the page, disconnect from the internet, and then open a file and edit it. Everything still works. A tool that was quietly uploading your file could not pass that test.
Nothing is stored either. Reload the page and the editor is empty again. The only thing kept between visits is a custom threshold profile, if you make one, in your own browser's local storage.
When to use something else
This editor is built for the common case: you have a subtitle file, something about it is wrong, and you want it fixed now without installing anything or making an account.
For heavier work — timing against an audio waveform, spell-checking across many files, batch processing a season of episodes, OCR from image-based subtitles — Subtitle Edit is the right tool and has been for years. It is free, open source, Windows-first, and genuinely excellent. If you subtitle professionally you probably already have it installed, and nothing here replaces it.
We would rather say that plainly than pretend a browser tab competes with a desktop application on its own ground.
Frequently asked questions
Is this SRT editor really free?
Yes, with no account, no trial, and no export limit. There is nothing to sign up for and no paid tier of this editor to upgrade to. It runs entirely in your browser, so it costs us nothing per file you edit — which is why it can stay free rather than becoming a funnel later.
Is my subtitle file really private?
Yes, and you can verify it. The file is read from your disk into this browser tab and every edit happens there. This feature has no upload endpoint, so there is nothing on our side that could receive your file. Load the page, disconnect from the internet, then open and edit a file: everything still works. Reload the page and nothing is kept.
Will it change my timecodes?
Not unless you ask it to. Formatting fixes — renumbering, comma decimals, spacing, blank lines between cues — never touch timing. Every operation that does change timing is a button you press: shifting, drift correction, frame-rate conversion, extending a cue, or enforcing gaps. Each one says so before you use it, and all of them undo with Ctrl+Z.
What is CPS and why does it matter?
CPS is characters per second — the subtitle's text length divided by how long it stays on screen. It is the number professional subtitlers work to, because it measures whether a viewer can actually finish reading. Netflix caps adult content at 20 CPS and children's content at 17. The editor shows CPS live on every cue and recalculates it as you type or retime.
Can it tell me who is speaking?
No, and no tool can. An SRT file contains only cue numbers, timecodes, and text — speaker identity is not part of the format, so it cannot be extracted from a file that never carried it. Getting speaker labels requires transcribing the original audio with speaker diarization, which is a different job from editing a subtitle file.
Does it work with VTT files?
Yes. You can open .vtt files and export as either .srt or .vtt. WebVTT positioning and styling data is dropped on import, because SRT has no equivalent for it — if you need that preserved, keep a copy of the original.
How do I fix subtitles that drift further out as the video goes on?
Use the two-point drift correction in the timing panel. Find one cue near the start and one near the end, enter the time each currently has and the time it should have, and everything in between is stretched proportionally. Drift like this usually means the file was authored against a different frame rate, which the frame-rate converter also fixes directly.
Can I edit more than one file at a time?
You can open several files at once and they are loaded into a single timeline in the order you selected them, which is useful for joining parts of a split recording. Editing genuinely separate subtitle files side by side is not something this editor does.