Brand kit
Carousel Fonts, Text Size and Contrast
A carousel is read on a phone, at about a third of the size you design it, often outdoors and in a hurry. Here is how big the text has to be, which fonts hold up, how much contrast you need and what to keep off a slide, on every platform.
What font size should carousel text be?
Design for the phone, not for your monitor. A phone shows a 1080 px slide about 360 points wide, a third of its width in pixels (big phones show it a little wider). So every size you set on the slide ends up about three times smaller on the screen people read it on.
Apple’s design guidelines put the smallest text on an iPhone at 11 points and the default reading size at 17 points. Multiply by three and you have the numbers for a 1080 px slide: about 33 px as the minimum for anything people should read, and about 51 px for comfortable body text. aiCarousels’ free LinkedIn PDF checker flags text under about 24 px as hard to read on a phone: treat that as the floor for small labels like a page number or your handle, not as a size for sentences.
Text sizes on a 1080 px slide, and what they become on a phone
| On the slide | On a phone (screen points) | Use it for | Drawn at phone size |
|---|---|---|---|
| 24 px | 8 pt | The floor: page numbers, your handle, a source line | Swipe for the five fixes |
| 33 px | 11 pt | The smallest text people should read (Apple’s minimum) | Swipe for the five fixes |
| 51 px Body text | 17 pt | Body text (Apple’s default reading size) | Swipe for the five fixes |
| 72 px and up | 24 pt and up | Headlines; WCAG’s “large text” for contrast (below) | Swipe for the five fixes |
Slide sizes divided by three: a phone that shows the slide 360 points wide. Screen points are Apple’s unit, about one CSS pixel each; WCAG measures large text in print points, and its 18 pt is about 24 of them. The last column is drawn at that on-screen size. Apple’s sizes: Human Interface Guidelines, Typography, and UI Design Dos and Don’ts.
Working on a bigger canvas? Scale the same way: at 2,160 px wide, double every number. A thin or condensed font needs more than these sizes, not less; Apple’s guidelines say to aim larger when a custom font has a thin weight.
The common carousel sizes are all 1080 px wide (1080 × 1350 for LinkedIn and Instagram 4:5, 1080 × 1440 for Instagram 3:4, 1080 × 1920 for TikTok), so these sizes work on every platform. The exact sizes for each app are in carousel sizes on every platform.
Which fonts work best for carousels?
The best carousel font is the one people don’t notice while they read. A few rules that hold on every platform:
- Two fonts are enough. One for headlines, one for everything else. Use size and weight for the rest of the hierarchy, not a third font.
- Let the headline font carry the personality. A serif, a heavy grotesque or a condensed display face works for a few big words.
- Keep the body font plain. Open letter shapes, a generous x-height (the height of the small letters) and a solid regular weight. Most clean sans serifs qualify.
- Avoid thin and light weights at small sizes. Apple’s guidelines warn that Ultralight, Thin and Light weights are hard to see, especially when text is small.
- Save script and all capitals for a few words. A handwritten font or a line in capitals is slower to read than lower case. Fine for a short headline, tiring for a paragraph.
- Keep them the same on every slide, and on every carousel. People learn your look, and a brand kit keeps the fonts and colours for each new carousel.
Font pairs that hold up on a phone
| Look | Headlines | Body text |
|---|---|---|
| Clean and modern | Space Grotesk | Inter |
| Editorial | Fraunces | Inter |
| Elegant | Playfair Display | Manrope |
| Friendly | Lora | Plus Jakarta Sans |
| Bold | Archivo Black | Inter |
Pairs from the free font pairing generator. All are Google Fonts, free to use commercially.
How much contrast does carousel text need?
Contrast is the difference in lightness between the text and what’s behind it, written as a ratio from 1:1 (none) to 21:1 (black on white). The web’s accessibility standard, WCAG 2.2, asks for at least 4.5:1 for text, and 3:1 for large text: 18 points, or 14 points in bold. WCAG says the same applies to images of text, and every carousel slide is one. Only logos and incidental text are exempt: words that are pure decoration, or that happen to be part of a photo. A slide’s headline and body text are neither.
WCAG puts 18 print points at about 24 px on a screen, the 24 screen points in the table above. On a slide that a phone shows at a third of its size, that is about 72 px (or about 56 px in bold). So headlines that big can use 3:1. Everything smaller, including your body text, needs 4.5:1.
Contrast examples for carousel colours
| Ratio | Body text (needs 4.5:1) | Headlines 72 px+ (need 3:1) | |
|---|---|---|---|
| AaDark text on white (#1F1A2E on #FFFFFF) | 16.9:1 | Yes | Yes |
| AaMid grey on white (#6F6A7B on #FFFFFF) | 5.2:1 | Yes | Yes |
| AaLight grey on white (#9C97A7 on #FFFFFF) | 2.8:1 | No | No |
| AaWhite on violet (#FFFFFF on #7F56D9) | 5.0:1 | Yes | Yes |
| AaWhite on orange (#FFFFFF on #E0663B) | 3.4:1 | No | Yes |
| AaDark text on the same orange (#1F1A2E on #E0663B) | 4.9:1 | Yes | Yes |
| AaYellow on white (#F5C518 on #FFFFFF) | 1.6:1 | No | No |
| AaThe same yellow on dark (#F5C518 on #1F1A2E) | 10.3:1 | Yes | Yes |
Ratios worked out with the WCAG formula for these exact colours. The orange shows the usual fix: keep the colour, change the text on it.
- Text on a photo changes contrast from letter to letter. Put the words on a solid panel, or darken the photo behind them, and check the lightest spot behind the text.
- Brand colours often fail as text colours. Use them for backgrounds, shapes and one accent word, and set the text in your dark or light neutral.
- Leave a margin. 4.5:1 is the minimum on a good screen. People read carousels in sunlight, with the brightness down. A higher ratio costs nothing.
How much text should go on one carousel slide?
Less than you think. If the words can’t fit at the sizes above, the slide holds too much.
- One idea per slide. A headline that makes the point, and a line or two that backs it up.
- A short cover. 12 words or fewer is the goal aiCarousels’ Ready to post check counts for the first slide.
- Split, don’t shrink. When a slide reads like a paragraph, make it two slides. Most platforms give you room: Instagram takes up to 20.
- Short lists. A few items per slide, each on one line.
In aiCarousels you can set this before anything is written: More options › Words per slide has Auto, Punchy (the fewest words), Balanced and Detailed. While you edit, text that can’t fit at a readable size gets a red Too long for this box tag instead of shrinking, and Shorten to fit trims it in your voice. That’s smart text fit. Or switch the slide to a layout with more room: your words move with it.
Is Unicode bold text bad for screen readers?
It depends where the bold is.
- On a slide: bold is the font’s own bold weight, drawn into the picture. It looks the same to everyone who can see it. No problem.
- In a caption: the “bold” you paste from a text formatter isn’t bold at all. It’s a different set of characters, the Mathematical Alphanumeric Symbols (U+1D400 to U+1D7FF), made for maths. Unicode recommends not using them in place of real formatting. Screen readers may skip them or read something like “mathematical sans-serif script t”, as the disability charity Scope explains.
So keep styled letters to a few words, and never on a name, a hashtag or the sentence people must understand. How to do it on each app is in bold text on LinkedIn and the Instagram text formatter.
Do fonts and text sizes change on LinkedIn, Instagram and TikTok?
The sizes above hold everywhere, because the slides are all 1080 px wide. What changes is what sits on top of them:
- TikTok and 9:16 slides: the app’s buttons and the caption cover the edges of the slide. Keep words away from them. aiCarousels draws these areas when you turn on Show safe zones.
- Instagram: the slide counter sits at the top right and the dots under the picture. Leave a margin at the edges, and write alt text for each slide.
- LinkedIn: the carousel is a PDF document. Page size, cover and the PDF itself are covered in LinkedIn carousel design tips and specs.
An example: a carousel built on these rules
Six slides at 4:5. Big headlines, one line of body text each, dark on light, and one font pair from cover to last slide.
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How to set fonts, text size and contrast in aiCarousels
- 01
Pick a theme
A theme sets the colours, fonts and style of the whole carousel, and works with every layout. Open Theme, filter by Light or Dark or a style such as Minimal or Professional, and click one to try it at once. See all of them on Themes.
- 02
Set the fonts and the text size
In Customize theme › Fonts, choose a Font pair, or the Headlines and Body fonts separately. Text size scales the text on every slide, and Headline case sets capitals or lower case.
- 03
Choose colours with enough contrast
In Customize theme › Colours, set Background, Headlines, Body text and Accent. Check your text colour against the background with the table above: 4.5:1 for body text.
- 04
Fix text that doesn’t fit
If a slide shows Too long for this box, press Shorten to fit, or change the layout. To make one slide’s text bigger or smaller, use Slide › Look › Text size (50% to 160%).
- 05
Check it on a phone, then save the look
Press Preview: the slides are drawn in a phone, in Light or Dark. The Ready to post list warns about text that’s small for a phone screen and text boxes too small for their words. When you like the look, Use in my brand kit keeps it for every new carousel.
Frequently asked questions
What font size should I use on a carousel?
On a 1080 px slide, body text of about 50 px reads comfortably on a phone, and nothing people should read belongs under 33 px. Headlines 72 px and up. Small labels like a page number can go down to about 24 px.
What is the best font for a carousel?
A pair: a font with character for headlines and a plain, sturdy sans serif for body text. Pairs like Space Grotesk with Inter, or Fraunces with Inter, hold up well on a phone. Avoid thin and light weights for small text.
What contrast ratio does text on a slide need?
At least 4.5:1 between text and background, and 3:1 for large headlines, as WCAG 2.2 asks. On a 1080 px slide, large means about 72 px, or 56 px in bold.
How many fonts should a carousel use?
Two at most: one for headlines and one for everything else. Use size and weight for the rest. Keep the same pair on every slide.
Can screen readers read the text on carousel slides?
Not when the slide is a picture: a screen reader can only read the alt text you add. On Instagram, add alt text to each slide that says what the slide says. On LinkedIn, a PDF needs real text, not pictures of text, for a screen reader to have anything to read.
