TXT to SRT: Turn a Script into Timed Subtitles

How to convert TXT to SRT

1. Paste your text into the box above, or press "Open a .txt file". The file is read in your browser.
2. Under "One subtitle per", choose "Sentence (long ones are split)" for prose, or "Line of the text" if you have already broken the text into one subtitle per line.
3. Set "Reading speed (chars/sec)". It starts at 15 and accepts 8 to 25.
4. If the subtitles must end with the video, type its length under "Fit to video length", for example 3:25.
5. Check the first subtitles in the preview, choose SRT or WebVTT under "Save as" and press "Make subtitles and download".

How the timing is worked out

Each subtitle gets a duration from its length: the number of characters divided by the reading speed. At 15 characters per second, a 45-character line gets 3 seconds. No subtitle is shorter than 1.2 seconds, so a one-word line like "Ready?" still stays up long enough to notice. A 100-millisecond gap separates one subtitle from the next, and the first one starts at 0:00.

"Fit to video length" keeps those proportions but stretches or squeezes everything, durations and gaps alike, so the last subtitle ends at the time you typed. A long sentence still gets more time than a short one; they all just slow down or speed up together.

How the text is split

In sentence mode, blank lines separate paragraphs, and each paragraph is cut into sentences at full stops, question marks and exclamation marks, including the Chinese and Japanese full-width forms. A sentence longer than 84 characters, the size of two full subtitle lines, is cut again: at a comma, semicolon or colon if one falls far enough along, otherwise at the last space that fits. Any piece longer than 42 characters is then wrapped onto two lines at the space nearest the middle, so lines come out balanced and words are never broken.

In line mode, every non-empty line of your text becomes one subtitle exactly as written. Nothing is wrapped or cut, so keep each line short yourself.

A worked example

Pasted text, in sentence mode at 15 characters per second:

Subtitle 1

00:00:00,000 --> 00:00:01,600, "Welcome to the workshop." (24 characters)

Subtitle 2

00:00:01,700 --> 00:00:06,900, two lines: "Today we will set up the printer, load" and "the filament and run a first test print" (78 characters)

Subtitle 3

00:00:07,000 --> 00:00:08,667, "without wasting material." (25 characters)

The second sentence is 104 characters, too long for one subtitle. Its only comma comes too early to be a useful break point, so it was cut at the last space within 84 characters, leaving a short third subtitle. A person would probably split it after "printer," and again before "and run". That is typical: the automatic split is a fair first draft, and the line breaks are worth reading before you publish. Subtitle segmentation explains where natural breaks fall.

Things that trip up the sentence splitter

• Abbreviations: a full stop after "Dr." or "e.g." is read as the end of a sentence, so "Dr. Rao will join us" becomes two subtitles. Remove the full stop or use line mode for those passages.
• Decimal numbers: "Version 2.5 is out" splits after "2." for the same reason. Write the number another way or join the pieces afterwards.
• Text with no punctuation, such as song lyrics or bullet lists: use line mode, with one subtitle per line.

Choosing a reading speed

15 characters per second is a relaxed default that most viewers can follow. Netflix's English timed-text style guide allows up to 20 characters per second for adult programmes and 17 for children's, with a maximum of 42 characters per line and two lines per subtitle. Lower the speed for young viewers, learners or dense technical text; raise it if subtitles have to keep pace with fast material. The mydubly subtitle editor flags anything above 21 characters per second, which is a useful upper limit to stay under. Subtitle timing guidelines goes into minimum durations and gaps.

Estimated timing is not speech timing

This is the important limit. The tool knows nothing about your video: it doesn't hear pauses, it doesn't know when someone starts talking, and it can't tell a slow speaker from a fast one. For text that is spoken in the video, estimated subtitles start in roughly the right place and drift apart from the voice within a few lines.

That makes this tool the right choice when nobody speaks the words: captions for a silent screen recording, written commentary over a music-only clip, on-screen instructions, a title sequence, or a rough draft SRT to style before the narration exists. When the words are spoken, you have two options:

• Let the AI subtitle generator make the subtitles from the audio. It times every line to the speech and works in 100 languages, for 1 credit (0.1¢) per minute with a minimum of 5 credits per file, so a 10-minute video costs 10 credits (1¢).
• Or create the SRT here and retime it against the video in the free subtitle editor, dragging each line on the timeline. If everything is late or early by the same amount, shift subtitle timing moves it in one go.

After you download

The file is a standard SRT: a number, a start and end time, the text, and a blank line for each subtitle, as described in what is an SRT file. Open it in the subtitle editor with your video to adjust lines, pick a style and render an MP4 with the subtitles burned in. To go the other way and strip times from subtitles, SRT to plain text shows how.

Limits

• An opened .txt file can be up to 20 MB; pasted or opened text is processed on your device and not uploaded.
• One reading speed applies to the whole text; adjust individual lines in the editor afterwards.
• Timing always starts at 0:00 and runs continuously, with no pauses unless you add them later.
• The text stays in the language you pasted; the tool doesn't translate.