Everyone else uses capitals. Why not me?

It is a style convention rather than a finding, and it spread because it looks confident in a still frame. That is a real reason, just not a readability one.

Do capitals suit a hook line?

They suit it better than they suit body text, because a hook is short, sits alone, and is meant to be looked at rather than read through.

What about mixed, with key words capitalised?

That is usually the strongest option. The line reads at normal speed and the capitalised word still lands.

Does it change how much fits on a line?

Yes, capitals are wider, so the same sentence takes more room and is more likely to wrap or run into the edge of the frame.

Can I set this once for a whole series?

On paid plans a saved style carries your choices across a run, so a series stays consistent without setting it each time.

Do capitals wrap more often?

Yes, because they are wider. The same sentence takes more room and is more likely to run into the edge of the frame.

Is there a case where all capitals is clearly right?

A hook line of three or four words that sits alone and is looked at rather than read through.

All Caps Subtitles, or Not?

Why do capitals read more slowly?

Ordinary lowercase words have an uneven outline, with letters rising and dropping, and readers recognise that shape before they process the letters. Capitals make every word the same rectangle, so the shortcut disappears. On a clip of a few seconds that difference is small but it is never in your favour.

What capitals cost and buy

The strongest arrangement is usually mixed: ordinary case for the line, capitals or colour on the one word that carries it.

Aspect	Capitals	Ordinary case
Reading speed	Slower, every word is the same rectangle	Faster, word shape is recognised before the letters
Room on a line	More, letters are wider	Less, so more fits before it wraps
Emphasis	None left, everything is already loud	Available, because capitals still mean something
Suits	Hooks and three word lines	Running text under a speaker
Risk	Whole clip reads as shouting	Looks plain if nothing is emphasised

Choosing the one word to emphasise

If only one word per line gets capitals or colour, pick the word a listener would hear stressed. In "I never said she stole it", the meaning changes depending on which word carries the weight, and the emphasis on screen should follow what the speaker actually did with their voice.

Numbers, names and the turn in a sentence ("but", "never", "only") are usually the strongest candidates. Avoid emphasising filler such as "really" or "so": it spends the visual accent on the least informative word and teaches the viewer that emphasis means nothing.

How capitals interact with other style choices

Capitals take more horizontal room, so the same sentence breaks into more lines. If your style already uses a large size, a thick outline or a wide font, switching to capitals can push a line onto two rows and cover more of the picture. Check the longest sentence in the clip after any change.

Condensed fonts were designed partly for this problem. If you like the energy of capitals, pairing them with a narrower face keeps the line length close to what lowercase would give. Heavy outlines and drop shadows also make capitals look busier than they do on lowercase, so a lighter treatment often balances them.

A quick way to decide for your audience

Produce two versions of one clip, one in capitals and one in ordinary case, and show them to three or four people from your audience without explaining the difference. Ask them what the clip was about rather than which they preferred. The version they summarise more accurately is the one that read better, whatever they say they liked.

Language matters as well. Some scripts have no capitals at all, and some languages carry meaning in the difference between upper and lower case. If you post in more than one language, set the style per language rather than forcing one habit across all of them.

Loud where it helps, plain where it does not

Use capitals on the shortest text. Three or four words carry it. A full line loses the benefit and keeps the cost.
Reserve them for emphasis. If everything is capitalised, nothing in the clip is emphasised.
Read your own clip once at speed. Watch it as a viewer would, once only, and see whether you finished each line.

Make one clip and read it back at normal speed.

Questions people ask

Everyone else uses capitals. Why not me?: It is a style convention rather than a finding, and it spread because it looks confident in a still frame. That is a real reason, just not a readability one.
Do capitals suit a hook line?: They suit it better than they suit body text, because a hook is short, sits alone, and is meant to be looked at rather than read through.
What about mixed, with key words capitalised?: That is usually the strongest option. The line reads at normal speed and the capitalised word still lands.
Does it change how much fits on a line?: Yes, capitals are wider, so the same sentence takes more room and is more likely to wrap or run into the edge of the frame.
Can I set this once for a whole series?: On paid plans a saved style carries your choices across a run, so a series stays consistent without setting it each time.
Do capitals wrap more often?: Yes, because they are wider. The same sentence takes more room and is more likely to run into the edge of the frame.
Is there a case where all capitals is clearly right?: A hook line of three or four words that sits alone and is looked at rather than read through.