Add Subtitles to Video Free: Burn In an SRT File Online

To add subtitles to a video, create an SRT file with numbered cues, start and end timecodes and the caption text, then either upload it next to the video as a separate caption track or burn it into the picture. Burning in uses a subtitle tool: load the video and the SRT, set the font size, and export.

Subtitles matter more than most people expect. Product videos on store pages and social feeds often autoplay without sound, tutorials get watched on trains, and viewers who are deaf or hard of hearing depend on them. The practical question is not whether to add them but which kind to add. This guide covers both, with the burn-in steps using Burn Subtitles to Video, which works inside your browser so the footage is never uploaded.

Free toolBurn Subtitles to VideoHardcode SRT subtitle tracks directly into video frames with custom styling. All processing runs privately in your browser without uploading video files.Open the tool

How to add subtitles to a video step by step

1. Write or export your SRT file. Type it in any plain text editor (the format is shown below) or export it from the transcription or editing app you already use. Save it with UTF-8 encoding and the .srt extension.
2. Play the video once with the SRT open. Check that each cue starts when the line is spoken and disappears before the next shot. Fixing timing in a text file takes seconds; fixing it after export means rendering again.
3. Open the tool and drop your video. MP4, MOV, WebM, MKV, AVI, FLV and 3GP files up to 1 GB are accepted. A preview player appears.
4. Drop the subtitle file into the second area. The area is labeled Subtitle file (.srt) and accepts SRT or ASS files. The file name appears with a change link in case you picked the wrong one.
5. Set the Font size. The field starts at 24. Leave it empty or enter 0 to use the size defined in the subtitle file, which matters mainly for ASS files that carry their own styles.
6. Choose the Output format. Keep MP4 (H.264) for Instagram, YouTube, Shopify, Etsy or Amazon uploads.
7. Press Burn in subtitles and review the result. The first run downloads the video engine once (about 30 MB). When encoding finishes, play the output and check a few cues at the start, middle and end before you download it.

Free toolBurn Subtitles to VideoHardcode SRT subtitle tracks directly into video frames with custom styling. All processing runs privately in your browser without uploading video files.Open the tool

What an SRT file looks like

SRT is the simplest caption format, and nearly every video platform and editor reads it. Each cue has four parts: a sequence number, a timecode line, one or two lines of text, and a blank line.

1
00:00:01,000 --> 00:00:03,400
Unbox the lamp and remove the tape.

2
00:00:03,800 --> 00:00:06,500
Twist the shade clockwise
until it clicks.

A few rules keep the file valid:

• Timecodes use hours, minutes, seconds and milliseconds, with a comma before the milliseconds, and an arrow made of two hyphens and a greater-than sign.
• Cues must be in order and should not overlap.
• Keep each cue to one or two short lines. Many subtitle style guides suggest roughly 35 to 42 characters per line so viewers can read it before it disappears.
• Save as UTF-8. Legacy encodings turn accented letters into garbage when the text is drawn.

Burned-in or separate: which subtitles do you need?

	Burned-in (open) subtitles	Separate (soft) subtitles
How they work	Text is drawn into every frame	SRT or similar file travels next to the video or inside the container
Viewer can turn them off	No	Yes, in players that support it
Plays the same everywhere	Yes, any player shows them	Depends on the player and platform
Multiple languages	One language per exported video	Several tracks on one video
Editing after export	Requires re-rendering the video	Edit the text file and upload it again
Encoding	Video is re-encoded	Video stays untouched
Best for	Social feeds, store product videos, ads, clips shared in chat apps	Long tutorials, courses, multi-language channels

Platforms such as YouTube let you upload an SRT file as a caption track, which keeps captions searchable and switchable. Social feeds, marketplace galleries and messaging apps often ignore separate caption files or strip them, which is why burned-in text is the reliable choice there. Check each platform’s current help page for which caption files it accepts.

Getting the look right

Font and size

The tool draws every cue in one built-in sans-serif font, bottom center, which is the conventional position for subtitles. Font size is a relative value rather than a fixed pixel count, so the same number looks similar on a 720p and a 1080p video. If captions feel too large on a vertical clip or too small on a landscape one, change the number by a few steps and render a short test.

ASS files for styled captions

If you need colors, outlines or custom positions, export an ASS file from a subtitle editor and load that instead of SRT. The tool uses the file’s own layout, although the typeface is replaced with the built-in font.

Test on a short clip first

Burning in re-encodes the whole video, which takes time on long footage. Cut a 10 to 20 second section first, burn the subtitles into it, and check readability on your phone before processing the full file.

Preparing the video

MKV recordings sometimes already contain soft subtitle tracks that disappear when the file is converted. The MKV to MP4 converter guide explains what survives that conversion. If you only need a playable file, the MKV to MP4 converter or the general MP4 video converter will produce one, and the guide to converting video files for any device or platform covers codec choices. Once subtitles are burned in, use the video compressor if the file is too large for an upload limit; compress after burning, not before.

Common mistakes

• Saving the SRT in a legacy encoding. Accented letters appear as random symbols in the video. Re-save the file as UTF-8 in your text editor and burn again.
• Using a period instead of a comma in timecodes. Some cues are skipped or the whole file fails to load. Write milliseconds as 00:00:01,000, not 00:00:01.000.
• Burning subtitles into a compressed download. The text edges and the picture both look soft. Always start from the original recording.
• Writing whole sentences into one cue. Viewers cannot finish reading before the cue disappears. Split long lines into two cues and keep each on screen long enough to read comfortably.
• Placing important visuals at the bottom of the frame. Captions cover prices, product details or on-screen instructions. Frame the shot with space at the bottom, or move key graphics higher.
• Burning captions when you need several languages. You end up rendering and storing one video per language. Use separate caption files on platforms that support them.

Frequently asked questions

What is the difference between burned-in and soft subtitles? Burned-in subtitles are drawn into the video frames and are always visible, while soft subtitles are a separate track the viewer can switch on or off. Burned-in captions play the same everywhere, but you cannot edit, translate or hide them after export.

Can I add subtitles in a language with non-Latin script? Yes for many alphabets, but not for every script. The tool draws text with one built-in sans-serif font that covers Latin-based languages such as English, Turkish, Spanish or Polish; scripts the font lacks, such as Chinese or Japanese, may render as empty boxes, so test a short clip first.

Why do my subtitles show strange characters? The SRT file was most likely saved in a legacy encoding instead of UTF-8. Open it in a plain text editor, save it again with UTF-8 encoding, and load the new file.

Does burning subtitles reduce video quality? Yes, slightly, because the whole video has to be re-encoded to draw the text into the frames. At the tool’s balanced H.264 setting the difference is hard to see on phones and laptops, but always burn subtitles into the original file rather than an already compressed copy.

Add your captions

Good subtitles come from a clean SRT file: correct timecodes, short lines, UTF-8 encoding. Decide whether viewers need the option to switch them off; if not, burn them in so they show up in every feed and player. Open Burn Subtitles to Video, drop your clip and your SRT, and export a captioned MP4 without sending your footage to a server.