Yes. Professional subtitles use normal punctuation and normal capitals. Netflix's English style guide tells subtitlers to follow U.S. English punctuation norms, and the BBC's guidelines say standard spelling and punctuation "should be used at all times". A sentence starts with a capital and ends with a period, question mark or exclamation mark, and whole lines in capitals are kept for shouting and for translating on-screen signs.
Short-form video bends three of those rules on purpose. Many creators use all-caps caption styles, leave the period off short captions, and write every number as a numeral. That works if you do it for a reason and stay consistent. Below are the rules from both style guides, what changes for Reels, Shorts and TikTok, and a style sheet you can copy.
Capitals: sentence case or all caps?
Sentence case is the default in every broadcast guide. The BBC Subtitle Guidelines (version 1.2.5, March 2026) ask for upper and lower case "as appropriate" and, in dialogue, keep capitals for two jobs: a single stressed word, as in "It's the BOOK I want, not the paper", and shouting. The same page warns against "large chunks of text in caps" because they are hard to read. Netflix uses all caps only for forced narratives, the subtitles that translate on-screen text such as a NO TRESPASSING sign, and switches back to sentence case for long passages of on-screen text to keep them readable.
YouTube does something similar in its automatic captions. Its help page on automatic captioning says English auto captions can show "the intensity of speech in all caps", along with sounds like sighs and gasps.
Short-form captions are a different case. When a caption is one to four words in a heavy font, capitals read as a design choice rather than shouting, and because capitals have no descenders, lines sit evenly. All caps works when:
- each caption is four words or fewer;
- the font is a heavy sans-serif with clear letter shapes;
- the video is short, roughly under three minutes.
Switch to sentence case for anything people will read for longer: talking-head explainers, tutorials, webinars and courses. If you want emphasis inside sentence case, use the BBC's trick sparingly: one word in capitals, or one word in a highlight color.
Periods and commas at the end of a caption
In broadcast subtitles, a full sentence ends with a period, even a short one. The exception is song lyrics: Netflix allows only question marks and exclamation marks at the end of a lyric line, and the BBC keeps song punctuation to a minimum, with a final full stop on the last line of the song. Pauses and trailing off get an ellipsis, and Netflix asks for the single ellipsis character rather than three typed dots.
The rule that matters most for short-form is about split sentences. When a sentence runs across two subtitles without a real pause, Netflix says not to add ellipses or dashes; the sentence simply continues in the next subtitle. In word-by-word or three-word captions almost every caption is a fragment of a longer sentence, so most of them should carry no end punctuation at all. A period belongs only on the caption where the sentence actually ends.
Many creators go one step further and drop that final period too, because a lone dot after a big word looks like a mistake on a phone. That is a reasonable house style for captions of one to four words, provided you keep question marks, which change the meaning, and apply it to the whole video. For two-line captions in sentence case, keep normal punctuation.
Other punctuation rules from Netflix's English (USA) Timed Text Style Guide that suit any captions:
- Avoid colons and semicolons; write two short sentences instead.
- Don't overuse commas: "I love you too" rather than "I love you, too".
- No double spaces, and no en or em dashes.
- Exclamation marks only for real shouting or surprise.
- For a shocked question, a question mark followed by an exclamation mark.
Italics and emphasis
Netflix italicizes a fixed list: narration, a character's unspoken thoughts, sung lyrics, unfamiliar foreign words, voices heard through a phone or speaker when that person is not in the scene, and titles of books, films and albums. It also allows italics for a word that is obviously stressed in speech when punctuation can't show it. The BBC uses capitals for stress on broadcast and treats italics for emphasis online as an experiment, noting there is "little research" on whether it works.
On social video, emphasis usually comes from color or size instead: the spoken word lights up, or one key word is set larger. That does the job of an italic and is easier to see on a small screen. Sound labels such as [laughs] or [music] follow their own conventions, which the guide to captioning for deaf and hard-of-hearing audiences covers.
Numbers and symbols
The two guides differ slightly, which tells you there is room for a house style:
- Netflix: zero to ten written as words, 11 and above as numerals, numerals for ages, and times written as "9:30 a.m.".
- BBC: numerals in general, with one to ten "often better spelled out"; numerals with units and for scores; a number that starts a sentence, or an emphatic one such as "hundreds of reasons", spelled out; commas in numbers over four digits, such as 1,500.
- Both: the rules are guidance. Netflix lets subtitlers break them for space or reading speed, and the BBC spells numbers out when it is editorially justified.
For short-form captions, numerals usually win. "3 tips" is shorter and faster to read than "three tips", and a number is often the point of the clip. Keep symbols to the ones people say aloud, such as % and $, and follow Netflix in spelling out "hashtag" when someone uses it as a verb.
What Netflix and the BBC say, side by side
As read on 19 October 2026, from Netflix's English (USA) Timed Text Style Guide (change log last updated 19 December 2025) and the BBC Subtitle Guidelines (version 1.2.5, March 2026):
| Rule | Netflix English (USA) | BBC |
|---|---|---|
| Punctuation | U.S. English norms; avoid colons and semicolons; no en or em dashes | Standard spelling and punctuation at all times |
| Capitals | Sentence case; all caps for on-screen text translations | Upper and lower case; caps for a stressed or shouted word |
| Song lines | No period or comma at line ends | Only question marks at line ends; a full stop at the very end |
| Pauses | One ellipsis character | Three dots |
| Emphasis | Italics when punctuation can't show it | Caps; italics online only as a trial |
| Numbers | Zero to ten as words, 11 and up as numerals | Numerals, with one to ten often spelled out |
| Sound labels | Lowercase in square brackets | White capitals on their own line |
| Line length | 42 characters, two lines at most | 37 characters on teletext; a share of the frame online |
If you came here for Netflix's line rules, those are the main numbers: 42 characters per line, two lines at most, up to 20 characters per second for adult programs and 17 for children's, and each subtitle on screen for between five-sixths of a second and 7 seconds. Netflix counts characters, not words, and it specifies the font only as a generic sans-serif; the Netflix subtitle font post covers what that means on screen. Where to break a line is covered in when to split subtitles into two lines, and the right length for vertical video in subtitle line length for short-form video.
A style sheet to copy
- Sentence case for two-line captions; all caps only for short captions in a heavy font.
- End punctuation only where a sentence ends; fragments get none.
- Keep question marks, always.
- Exclamation marks only for real shouting or surprise.
- No colons, semicolons or dashes; split into short sentences.
- One ellipsis character for a trailing thought or a pause.
- Numerals in short-form captions; words for a number that starts a sentence.
- Emphasis by color or one capitalized word, never whole capitalized lines in long videos.
- Sound labels in brackets and lowercase, only when the sound matters.
- Brand and creator names written the way they write them.
If you work with a team, put these ten lines at the top of your subtitle style guide so every editor makes the same calls.
Punctuation and capitals in CapsAI
CapsAI keeps the case of your transcript unless you pick a style that sets everything in capitals. Among the eight free styles, Base, Beast, Newsroom and Poppins Italic are uppercase, while Tommy Soft, Story, Shine and Ice keep the case as typed. Every caption's text can be edited in the browser editor before export, so you can delete periods from fragments, fix capitals on names and change "three" to "3". The export is one MP4 with the captions burned in, so whatever punctuation you leave is what every viewer sees.
What to do next
Pick the rules above that fit your format, then try them on a short clip: upload it, choose a sentence-case or all-caps look from the caption styles, and edit the punctuation in the draft. New accounts get 3 free minutes, packs start from $4 (₹49 in India, €4 in the euro area), and watermark-free export comes with every paid pack.
