About Caption Fit Lab

Caption Fit Lab measures characters per second, line length, and overlaps, then previews the cues in a 9:16 frame.

Caption Fit Lab is a free browser tool. There is no account. Files, dates, captions, and measurements you type stay in the tab you have open. This site does not upload them to a server we control.

The worked examples on each tool page are written in HTML: inputs, result, and assumptions. They are illustrations you can check. They are not a certificate, a government form, or a promise that a portal, printer, or platform will accept the file.

Who it is for

People writing captions for Shorts, Reels, and similar 9:16 video who need a speed check and an SRT export.

What we will not do

• We do not ask you to click ads, and we do not pay anyone to click them.
• We do not sell a file you drop into a tool.
• We do not pretend a calculation is official when the source is a public holiday list or a print rule of thumb.

Contact

Questions about a result or about advertising: hello@captionfitlab.example.

Shorter answers are on the FAQ.