Free online subtitle tools for SRT & WebVTT files
Convert subtitle formats, shift timings, validate errors, merge split cues and extract dialogue — all inside your browser. Your subtitle files never leave your device.
Search 25 subtitle tools by task
Every utility runs locally in your browser. Search by format (SRT, VTT), action (convert, shift, validate) or keyword.
SRT to VTT Converter
Convert SubRip .srt files to WebVTT .vtt with a proper WEBVTT header.
ConversionVTT to SRT Converter
Convert WebVTT captions back to standard SubRip .srt format.
ConversionFormat Converter
Convert between SRT and WebVTT in either direction.
ConversionSRT to Plain Text
Extract dialogue from an SRT file without timestamps or cue numbers.
TextVTT to Plain Text
Turn WebVTT captions into a clean plain-text transcript.
TextSubtitle to JSON
Export subtitle cues as structured JSON with start, end and text.
ConversionJSON to SRT
Rebuild an SRT file from JSON cue data.
ConversionSRT Time Shifter
Shift every cue forward or backward by any number of seconds.
TimingMillisecond Shifter
Adjust cue timings with millisecond-level precision.
TimingDuration Report
See total runtime, average duration and longest/shortest cues.
TimingSRT Validator
Check SRT files for timestamp errors, overlaps and empty cues.
ValidationVTT Validator
Validate WebVTT files for common structural problems.
ValidationLine Length Checker
Find cues that exceed recommended reading-length limits.
ValidationFormat Detector
Inspect subtitle content and see the likely format with confidence.
ValidationWord Counter
Count words in subtitle dialogue for reading-speed analysis.
TextLine Counter
Count cue blocks and individual dialogue lines.
TextCase Converter
Convert dialogue to UPPER, lower, Title Case or Sentence case.
TextSearch & Replace
Find and replace text across all cues with change preview.
TextEncoding Cleaner
Strip UTF-8 BOM, remove zero-width characters and fix line endings.
TextSubtitle Merger
Combine two subtitle files into one chronological file.
StructureSubtitle Splitter
Split one subtitle file into equal parts as separate downloads.
StructureCue Renumbering
Renumber SRT cues sequentially from 1 to N.
StructureRemove Empty Cues
Delete cue blocks whose dialogue is empty or whitespace-only.
StructureRemove HTML Tags
Strip inline HTML, ASS override tags and HTML entities from cues.
StructureSubtitle Preview
Preview cue timings and dialogue in a clean visual list.
StructureFormat Cleaner
Normalize spacing, line endings and cue numbering across a file.
StructureBrowse tools by category
Pick a category to see every subtitle tool that fits your task.
Conversion tools
SRT to VTT, VTT to SRT, subtitle to JSON, JSON to SRT and format conversion.
Timing tools
Time shift, millisecond adjustments and duration reports.
Validation tools
Validate SRT and VTT files, check line lengths and detect formats.
Text tools
Word count, line count, case conversion and search-replace.
Structural tools
Merge, split, renumber, remove empty cues and clean formatting.
All 25 tools
See every subtitle utility in one place with live search.
Your subtitle files never leave your browser
Subtitle Convert is a fully static site. There is no backend service. When you load a file, your browser reads it locally and every tool operates on the text inside your device. Nothing is uploaded, nothing is stored on a server.
Local file processing
Files are read with the browser's FileReader API. Their contents are never transmitted to any server.
No accounts, no tracking
No sign-up, no user accounts and no analytics that touch your subtitle text.
Works offline
Once the page loads, every tool keeps working even if the network disconnects.
How Subtitle Convert works
Three steps. Zero uploads. Your subtitle files stay on your device.
Open a tool
Choose any of the 25 subtitle utilities — from SRT-to-VTT conversion to timing adjustment and validation.
Load your subtitle file
Upload an .srt, .vtt or plain text file, or paste subtitle text directly into the workspace.
Process & download
Click the action button. The tool processes everything in your browser and downloads the result instantly.
Supported subtitle formats
SRT and WebVTT are supported end-to-end. Plain text and JSON are supported for text and data workflows.
SRT — SubRip
The most widely supported subtitle format. Sequential cue numbers, comma-separated millisecond timings and dialogue lines. Fully supported across all conversion tools.
WebVTT
Required for HTML5 <track> captions. Starts with a WEBVTT header, supports cue identifiers, optional positioning settings and period-separated timestamps. Fully supported.
Plain text & JSON
Produce a timestamp-free transcript or structured JSON cue data. JSON can be round-tripped back into SRT via the JSON to SRT tool.
Built for everyone who works with subtitles
Practical subtitle work for creators, translators and students.
Video editors & YouTubers
Fix subtitles that are out of sync, convert SRT files downloaded from platforms to WebVTT for the web, and merge bilingual subtitle tracks into a single file.
Translators
Renumber cues after partial translations, strip HTML tags inherited from a source file and export plain text to feed a translation memory.
Students & researchers
Extract dialogue from subtitle files for text analysis, count words for reading-speed studies and check line length for comprehension research.
Web developers
Generate JSON cue data for a JavaScript video player, validate WebVTT before shipping and preview cue structure without opening a heavy editor.
Learn subtitle workflows
Guides, blog articles and stories from people who work with subtitle files every day.
How to edit SRT files
A practical walkthrough for opening, editing and saving SRT subtitle files without breaking their structure.
How to sync subtitles
Fix subtitles that drift out of sync and align them with the audio track using time shifting.
SRT vs VTT
The differences between SubRip and WebVTT, when to use each and how conversion works.
Subtitle formats explained
SRT, VTT, ASS, SSA, SBV, SUB and JSON — what each format is good for.
The history of subtitles
From silent-film intertitles to streaming captions — how subtitle technology evolved.
Subtitle glossary
Every subtitle term you need, from CPS to cue timing and beyond.
Frequently asked questions
Are these subtitle tools really free?
Yes. All 25 tools are free with no usage limits and no sign-up. Subtitle Convert is supported by advertising and the tools themselves will always remain free.
Do you store my subtitle files?
No. Files are read by your browser and processed entirely on your device. Nothing is uploaded to a server. See the privacy policy for the small amount of metadata the hosting provider logs.
What subtitle formats are supported?
SRT (SubRip) and WebVTT are the primary formats. The parsers are tolerant of common variants — period vs comma millisecond separators, missing cue numbers and WebVTT style blocks — but this is not a full IEC 14496-30 compliance implementation. For unusual files, check each tool's limitations section.
Will converting change my subtitle content?
Conversion tools preserve cue text and timings. Only the file structure (header, timestamp separator, cue numbering) is rewritten. Format converters never alter the words themselves.
Do these tools work on mobile?
Yes. Every tool is tested from 320px upward. File input, text input, download and copy all work in Android Chrome and iOS Safari. Very large files may be slow on lower-end phones.
Can I use these tools commercially?
Yes. You can use the output in personal, educational or commercial subtitle projects. You may not resell the tools themselves. See the Terms of Use for details.
Why do some tools show warnings instead of blocking the operation?
Because subtitle files in the wild vary. A cue that overlaps by 5ms is suspicious but often intentional. The validator surfaces issues and lets you decide whether to fix them.
Explore more from Subtitle Convert
Documentation, stories, resources and everything else behind the site.
Blog
Articles on subtitle formats, accessibility and workflows.
Guides
Step-by-step tutorials for everyday subtitle tasks.
Stories
Eight long-form stories about the craft of subtitling.
Formats
Complete reference pages for every subtitle format.
Resources
Glossary, tool comparisons and software lists.
Support
Help center, FAQ, bug reports and feature requests.
Company
About the project, team, roadmap and community.
Legal
Privacy, terms, cookie policy and accessibility statement.