Designing a LinkedIn Carousel That Is Readable on a Phone

A carousel is one of the few LinkedIn formats where design does real work. A text post either reads or it does not. A carousel can be well written and still be unreadable, because the words are trapped inside pictures, and the pictures are being viewed on a screen about the size of a playing card.

So the useful question is not “how do I make this look good”. It is “what survives a phone”. Almost every rule below falls out of that one constraint.

Why should I design a LinkedIn carousel for a phone first?

You do not need a statistic to justify this, just a look at the shape of the thing. The LinkedIn feed is a narrow single column. On a phone that column is about the width of the screen, and a carousel card sits inside it with a caption above and reactions below. The slide you built at full size on a large monitor is being shown at a fraction of that, on a device someone is holding in one hand, often in poor light.

Two more things about that moment matter. The reader has not committed to you — they are scrolling, and your first slide has to be legible before they decide to care. And they are swiping with a thumb, so the interaction is fast and shallow. Design that assumes careful study will not get careful study.

The practical consequence: build at a comfortable working size, then judge at phone size. Never the other way round.

How big should the text be on a carousel slide?

There is no official LinkedIn number for this, and anyone who gives you one has invented it. What there is instead is a reliable working method.

Pick a canvas — square (1080 × 1080 pixels) and portrait (1080 × 1350) are the two common choices, and portrait takes more vertical space in the feed. Check LinkedIn’s own help pages for current dimension and file-size limits, because those change. Then set type as a proportion of the canvas rather than in abstract points.

These are starting points, not rules. The real test is the one below.

The screenshot test

Export a slide, put it on your phone, and look at it from about an arm’s length away — the distance you actually hold a phone, not the closer distance you use when checking your own work. If the headline does not read instantly, it is too small. Then do the reverse on your computer: shrink the image until it is roughly the width of a phone, and squint. Whatever disappears is decoration, and decoration is fine, as long as it is not the thing carrying your meaning.

A blunter version of the same test: if you would not put that sentence on a road sign, it is too long for a slide.

Which fonts hold up on a small screen, and which do not?

Thin and ultra-light font weights are the most common way a good carousel becomes unreadable. They look elegant at 400% zoom in a design tool. On a phone the strokes are close to a single pixel wide, image compression softens them further, and they dissolve against anything but a flat background.

What holds up:

• Regular, medium, semibold and bold weights. There is plenty of range in there. You almost never need Light or Thin.
• Fonts with open letter shapes. Letters such as a, e and s with narrow gaps inside them close up at small sizes and turn into blobs.
• Two weights of one family, rather than two different families. The jump from bold to regular does the job the second font was going to do, and it never clashes.

What does not hold up: condensed faces at small sizes, script and handwriting fonts for anything longer than a signature, all-capitals beyond a few words, and letter-spacing pushed so wide that words stop reading as single units. Tight line spacing hurts too — lines that almost touch are hard to separate at speed.

How much contrast do text and background need?

This one has an actual published standard behind it, which is a relief after all the guesswork. The Web Content Accessibility Guidelines, published by the W3C, set a minimum contrast ratio of 4.5:1 between text and background for normal text, and 3:1 for large text (defined there as roughly 18pt, or 14pt bold, and above). Carousel headlines count as large text; small labels do not.

Any free contrast checker will test a pair of colours in seconds. Do it once for your template and you never think about it again.

Two failure patterns are worth naming, because they are so common:

• Text laid over a photograph. A photo is many colours, so the ratio changes across the sentence — the first three words read and the rest do not. Put a solid or heavily darkened panel behind the text, or move the text off the photo.
• Mid-tone on mid-tone. Grey on light grey, or a brand colour on a slightly different brand colour, often passes on a bright laptop and fails outdoors on a phone at half brightness.

Why is one idea per slide the rule that matters most?

Every other decision gets easier once each slide carries exactly one idea, because the slide stops competing with itself for space. One idea means one headline, at most one supporting line, and nothing else fighting for attention.

The temptation runs the other way. You have a point with four sub-points, and it feels efficient to put all five on one slide. But a swipe costs the reader almost nothing, and a crowded slide does — it costs them the moment where they work out what to look at first. Five slides with one line each get read. One slide with five lines gets skipped.

A test that catches this reliably: read the slide out loud. If you need a breath in the middle, it is two slides.

What margins and alignment should I use?

Margins are the least glamorous part of carousel design, and the part that most visibly separates a deck that looks made from one that looks assembled.

• Keep the margin generous. Around 8–10% of the canvas width on every side is a comfortable default. Text near the edge feels cramped on a small screen, and the edges are where a rounded card corner or a swipe indicator may sit.
• Keep it identical on every slide. If a headline starts 90 pixels from the left on slide one, it starts 90 pixels from the left on slide nine. Consistency is what makes a set feel like a set.
• Left-align anything longer than a few words. Centred text is fine for one short headline and tiring beyond that, because the eye has to hunt for a new starting point on every line.
• Anchor headlines to the same spot. Pick top-left, or centre, and stay there. When the position jumps between slides, every swipe makes the reader search the slide again.
• Leave real empty space. On a small screen, empty space is the thing that makes the filled space legible.

How much colour should a carousel use?

Less than you think. A workable palette is a background, a text colour, and one accent — the accent used sparingly, for the word or number you want the eye to land on. When everything is highlighted, nothing is.

Two more practical points. Decide whether your deck is dark text on a light background or light text on a dark one, and stay consistent — flipping between the two mid-deck is jarring on a phone in a dim room. And never let colour be the only thing carrying a meaning: if red means “avoid” and green means “do this”, label them in words too. A portion of your readers will not tell those two apart, and a label costs you nothing.

Are LinkedIn carousels accessible?

Partly, and it is worth being honest about the limits.

The core problem is simple: text that lives inside an image is invisible to a screen reader. Software that reads a page aloud sees a picture, not the sentence you set in 90px bold. So a beautifully designed carousel can be, to some readers, an unlabelled blank.

What you can do about it:

• Add alternative text wherever the field is offered. LinkedIn provides an alt-text field for images. Check whether it appears for the post type you are using, and if it does, describe the substance of the slide rather than writing “slide 3”.
• Put the real content in the caption. The caption is plain text, so screen readers can read it and search engines can index it. Summarising the key points there is the most reliable accessibility fix available to you, and it helps everyone who would rather not swipe.
• Meet the contrast minimums described above. Low vision is far more common than total blindness, and contrast helps the most people for the least effort.
• Avoid tiny text and thin strokes. The same choices that help a rushed commuter help a reader with impaired sight.

A short checklist before you post

• Viewed on a phone at arm’s length, does every headline read instantly?
• Is any font weight lighter than Regular doing important work?
• Does every text-and-background pair clear 4.5:1, or 3:1 for large headlines?
• Does each slide carry exactly one idea?
• Are the margins identical on every slide?
• Is the accent colour used on a few words rather than many?
• Does the caption say what the deck says, in plain text?

How do I publish the finished deck?

Design and publishing are separate jobs. You have two routes: save the deck as a PDF and publish it as a document post, or save the slides as individual images and publish them as a multi-image post. The PDF route usually suits a designed deck better, because the pages keep their order and proportions.

If you would rather not open the LinkedIn composer, a connector can handle publishing from a chat window. Kalovio is a free hosted LinkedIn MCP server — MCP being the Model Context Protocol, an open standard that lets an AI assistant such as Claude or ChatGPT use outside tools. You upload the PDF or the images, write the caption, and it publishes through LinkedIn’s official API. Two things to know first: multi-image and document posts go through LinkedIn’s newer versioned interface, which is not switched on for every self-serve app, so try it on your own account and see — a refusal is reported clearly rather than failing quietly. Document posts also publish immediately; they cannot be scheduled yet.

None of that changes the design work. The slides still have to survive a phone. That is the part worth your time.