Animated captions: what makes them work, and how to check them
Animated captions show each word as you say it, with the key word picked out in color. They help only if they are right (names, numbers, brand words), easy to read (strong contrast, a few words at a time) and clear of the buttons of TikTok and Instagram. CapCut, Kapwing, Submagic and Captions all offer them; none of the pages we read proves its accuracy. Rushly AI adds them in the style you pick, and you read the text before you post.
By Quentin, video editor, founder of Rushly AI. Sources read on October 29, 2026.
How to do it in three steps
- Upload your video to a tool that transcribes your voice.
- Pick a caption style: font, color of the key word, how words enter.
- Read the text, fix what is wrong where your tool allows it, then export in 9:16.
In Rushly AI you pick the caption style, and the captions are drawn into the picture of the exported 9:16 MP4. Your first video is free, with no credit card. Read every caption before you post.
What an animated caption is
A classic subtitle shows a whole line, then replaces it. An animated caption gives each word its own moment. The usual effects:
- karaoke: the current word changes color;
- one word at a time, in the middle of the frame;
- small groups of words, with one key word in an accent color.
Kapwing's AI editor page lists word-by-word captions with colors, fonts and animations you can change. For the buttons that hide them, see captions for TikTok and Reels.
What makes them good
1. They are right. This matters most, and no page we read proves it. See below.
2. They are readable. The W3C's accessibility guidelines (WCAG 2.2, level AA) ask for a contrast ratio of at least 4.5 to 1 for normal text and 3 to 1 for large text. They were written for websites, so take them as a reference for captions, not as a rule.
3. They say little at a time. Netflix's English style guide allows 42 characters per line, two lines and up to 20 characters per second for adult programs. Those rules are for films. A quick check with the 20 characters per second figure: a group of 20 characters needs about one second on screen, and a 30-character group needs about a second and a half. Our arithmetic, as a reading-speed reference only.
4. They stay in the safe zone. The app's interface covers the bottom and the sides. The numbers and their limits are in captions for TikTok and Reels. Rushly AI keeps its caption text between x 140 and 940 and y 269 and 1248 on a 1080 by 1920 frame.
5. They move without tiring. Our advice as an editor: one effect per caption. We found no study on word-by-word captions.
Accuracy: what the tools say, what we know
Automatic captions come from a transcript, and the transcript is only as good as the audio.
- Submagic says it generates caption styles "in 123 languages with 99% accuracy". Its page does not explain how that was measured.
- YouTube's help says automatic captions can misrepresent speech because of mispronunciations, accents, dialects or background noise, and that they may not be generated for videos with poor audio or overlapping speakers.
- Kapwing's page gives no accuracy figure for captions.
We did not find a measurement for the spontaneous speech of a creator, with slang, brand names and fast delivery. We have not published an accuracy measurement for Rushly AI either. Read every caption before you post, and look first at proper names, prices and numbers, and the words you coined.
The caption styles in Rushly AI
Rushly AI has 14 caption styles. The style sets how the captions look: font, case, animation and which word stands out. Per the home page, Solo gives access to 3 styles and Creator and Pro to all of them. Captions never show an "um", a "hum" or a cut-off word, even though the transcript sees them, so the cutting step can remove them.
| Style | How to recognize it |
|---|---|
| Clean | one simple line of text beside your face |
| Classic | one small, crisp white line, centered |
| Ali | each word in black on a light pill |
| Legend | golden capitals, the key word bigger |
| Thin italic + bold | a thin yellow italic, key words in bold |
| Editorial Serif | one word at a time, the key word big, in green serif |
| Pushed review | a thin serif, words light up one by one |
| Écrin | crisp white text, the key word in italics |
| Boxed word | one key word per sentence, in a red box |
| Yellow block | a small white script, then the key word in giant yellow |
| Frost | a frosted glass pill, words light up one by one |
| Accent | the key word in fiery italics, gently rippling |
| Sky word | the key word, giant, filled with a drifting sky |
| Two fonts | a few small words, then the key word, big |
Which tool?
| Tool | What we read | Worth knowing |
|---|---|---|
| CapCut | Captions, Auto Captions, language, Generate (help, March 24, 2026) | the help does not say which options are free |
| Kapwing | word-by-word captions, colors, fonts, animations | free plan: watermark, 4-minute exports, 720p; Pro $16 a month |
| Submagic | 123 languages and 99% accuracy advertised | no method published for the figure |
| Captions | caption templates: 1 on the free plan, 100+ on paid plans | Max plan $24.99 a month (iOS prices), 500 credits |
| Rushly AI | word-by-word captions in one of 14 styles, drawn into the exported MP4 | accuracy not measured by us; the first video is free and carries a watermark that paid plans remove |
Prices read on October 29, 2026. They change, so check the page before you subscribe.
What about people who watch without sound?
You will see figures like "85% watch with the sound off". We did not verify any of them, so we do not use one. What we did read is a 2024 PLOS ONE study with 168 viewers: watching a TV episode without sound lowered comprehension a little (77.7% against 81.3%) and raised mental effort a lot (3.07 to 4.84 on a 7-point scale). Both versions had subtitles, so it says nothing about how good captions must be. Our reading: with the sound off, the text carries everything, so a wrong or unreadable caption costs the viewer time.
When Rushly AI is not the right choice
- You only want captions on a video that is already edited. CapCut, Kapwing or a caption tool will do.
- Your video has several voices, or nobody talks to the camera. Rushly AI is for one person talking to the camera.
- You want to place and style each caption by hand. Rushly AI builds the captions from your voice and the style you pick.
For the full edit around the captions, see our AI video editor page, and the steps that come before: remove filler words and remove silences.
Sources
Pages read on October 29, 2026:
- Kapwing, AI video editor: kapwing.com/ai ; pricing: kapwing.com/pricing
- CapCut Help, "Auto captions" (March 24, 2026): capcut.com/help/auto-captions
- Submagic: submagic.co
- Captions, pricing: captions.ai/pricing
- W3C, WCAG 2.2, "Understanding Success Criterion 1.4.3: Contrast (Minimum)": w3.org/WAI/WCAG22/Understanding/contrast-minimum.html
- Netflix Partner Help Center, English Timed Text Style Guide (change log entry December 19, 2025): partnerhelp.netflixstudios.com/hc/en-us/articles/217350977-English-Timed-Text-Style-Guide
- YouTube Help, "Use automatic captions": support.google.com/youtube/answer/6373554
- PLOS ONE, Szarkowska et al., 2024, eye-tracking study of watching with and without sound: journals.plos.org/plosone/article?id=10.1371/journal.pone.0306251
To see animated captions on your own video, try Rushly AI and pick a style on your first free video.
Frequently asked questions
What are animated captions?
Captions where each word appears when you say it, often with the current word or a key word in a different color. They are also called dynamic captions, word-by-word captions or karaoke captions. The point is that the eye follows the voice.
How many words should show at once?
Few. Netflix's English style guide allows 42 characters per line, two lines at most and up to 20 characters per second for adult programs, but that is for films, not vertical word-by-word text. For a short video, a small group of words at a time is enough. Rushly AI's own rules aim at no more than 20 characters per second and keep each group of words on screen for at least 0.8 seconds.
Are automatic captions accurate?
Often, never always. Submagic advertises 99% accuracy in 123 languages, but its page does not describe how that was measured, and YouTube says automatic captions can misread accents, dialects and background noise. We have no measurement of our own yet, so read every caption before you post, names and numbers first.
Can I make animated captions in CapCut for free?
CapCut's help (March 24, 2026) gives the route: Captions, Auto Captions, choose the language, Generate. On mobile you tap Captions in the bottom menu and choose a template. The page does not say which options need a paid plan, and we did not test them in the app.
Do captions matter if viewers watch with the sound on?
They still help with names, numbers and noisy places. We have not verified any figure for how many people watch with the sound off, so we do not quote one.
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