Captions and Transcripts

On this page:

Benefits of Captions

  • Ensures a diverse audience can view your video, including deaf and hearing impaired, people for whom English is a second language, and in situations where noise is an issue or volume is turned off

  • Increases comprehension and retention.   Seeing text and hearing audio together reinforces learning concepts, fosters understanding and use of unique vocabulary terms, and helps those with learning disabilities

  • Increases Search Engine Optimization (SEO) by making content in video easier to find

Closed Captions: Adding Captions to Video

In order to caption a video, you must either own it or have permission to caption it. If you do not own the video, contact the owner for permission.

Video Captioning Service Providers:

Do-It-Yourself Video Captioning Tools:

  • Amaraopens in new window - free, open source, online captioning tool
  • YouTube Captioningopens in new window
  • Overstreamopens in new window free, online tool designed to create, synchronize, and stream subtitles onto an online video in any language (works with YouTube, Vimeo, Google Video)
  • MovieCaptioner opens in new window closed captioning software for Mac and Windows (works offline)
  • Caption Format Converter Toolopens in new window free tool converts SRT or SBV to various caption formats 

Guidelines for Writing Captions

Adapted from DCMP Captioning Guidelines for Educational Mediaopens in new window

  • Place captions on the bottom two lines of the screen as long as it does not interfere with existing visuals. If there are visuals appearing on the bottom of the screen, then place captions at the top of the screen.
  • Make captions two lines or less.
  • Make caption length 32 characters or less per line.
  • Left-align the captions.
  • Divide longer sentences at a logical point where speech normally pauses.
  • Use font type Helvetica medium or similar type.
  • Use a translucent box so that text will be clearer, especially on light backgrounds.
  • Use sans serif characters with a drop or rim shadow, and space proportionally.
  • Caption higher education media at a presentation rate of approximately 120-130 words per minute. Caption theatrical presentations at a near-verbatim rate. No caption should remain on-screen less than two seconds or exceed 235 wpm.
  • Editing is performed only when a caption exceeds the presentation rate limit. Edit to maintain original meaning, content, essential vocabulary, and meet presentation rate requirements. For more details on editing, see in new window
  • Grammatical rules for captioning punctuation, quotations and spelling are found at in new window
  • Special considerations for captioning sounds, speaker identification, numbers and music are listed at in new window

Live Captions: Captioning a Meeting, Lecture, Webinar, etc.

A live-captioned event provides accessible content to attendees with hearing impairments or for whom English is a second language.  Live captions also boost retention for the audience at large.   CART, or Communication Access Realtime Translation, is the term used to describe trained service providers that can create a visual transcript of audio in real-time for your audience, whether they be in attendance at your event or watching it online via a webinar platform.   CART providers work live or via remote access.  Individuals seeking CART as an accommodation may visit either Student Disability Servicesopens in new window (MIT Students) or Human Resources Disability Servicesopens in new window (MIT Employees).

CART providers


Transcripts provide a textual version of the content that can be accessed by anyone who cannot hear, play, or otherwise use an audio file. Transcription of audio allows users to access and read the content as text. Transcription can be done manually or, for a fee, via a transcription provider: