Font size rules for readable slides

Small text is one of the most common slide problems and one of the easiest to fix. It usually happens because you had more to say than fit. What looks readable on your laptop can be unreadable from the back of a seminar room.

This article gives you practical size ranges, explains why they vary, and shows how to test your own deck.

Why there’s no single magic number

Font size in slide software is measured in points, but how big that text actually looks depends on several things:

• The size of the screen or projection. A large lecture-hall screen and a small meeting-room television show the same slide very differently.
• How far away people sit. The back row of a long room needs bigger text than a table of four.
• The font itself. Some fonts look larger or smaller than others at the same point size.
• The slide size. Widescreen and standard slides scale differently on the same screen.
• How it’s viewed. On a video call, people may be watching your slides in a small window on a laptop or even a phone.

So treat the numbers below as starting points that work in most situations, then test in your own setting. If you’d like to go deeper on choosing sizes by room and screen, there’s a longer guide to presentation font sizes as well.

Starting sizes that work for most presentations

These are sensible ranges for a typical presented deck on a standard widescreen slide:

Text type	Suggested size
Slide titles	32–44 pt
Main body text	24–32 pt
Secondary text, captions	18–24 pt
Chart labels and axis text	18 pt or larger
Footnotes and sources	14–16 pt (use sparingly)

A simple rule if you remember only one thing: keep body text at 24 pt or larger for anything you need the audience to read.

If you’re presenting in a large room, go towards the upper end of each range. If your deck is a reading deck that people will open on their own screens, you can use smaller sizes, though body text below about 14 pt still gets hard to read.

The most common size mistakes

Shrinking text to make it fit

This is the big one. When a slide has too much on it, slide software often reduces the text size automatically, and it’s easy not to notice. If you find yourself at 16 or 18 pt for body text on a presented slide, the problem isn’t the font size. It’s the amount of content.

The fix: turn off automatic text shrinking if your software allows it, and cut or split the slide instead. If you need help cutting, see how many words per slide is too many.

Tiny chart labels

Charts copied from spreadsheets often carry their original small labels. On a slide, axis labels and data labels can end up much smaller than the body text around them.

The fix: after pasting a chart, increase all its text to at least 18 pt. Remove labels you don’t need, which also frees space for the ones you do.

Inconsistent sizes

Body text at 28 pt on one slide and 20 pt on the next looks untidy and makes the smaller slide feel less important.

The fix: pick one size for each text type and use it on every slide. Using your software’s slide layouts or master slides makes this much easier.

Thin or decorative fonts

Light weights, condensed styles and script fonts can be hard to read at any size, especially on projectors.

The fix: use a clear, regular-weight font for body text. Save stylistic fonts for, at most, a title slide.

Size is only part of readability

Large text can still be hard to read if other things are wrong. Check these too:

• Contrast. Dark text on a light background, or the reverse. Pale greys and yellows can wash out on a projector.
• Line length. Very long lines across a widescreen slide are tiring to read. Shorter lines, or two columns, help.
• Spacing. A little extra space between lines and around text boxes makes slides easier to scan.
• Background. Avoid placing text directly over busy photos.

How to test your slides

Nothing beats testing. Here are three quick ways.

The distance test

Put your slides in full-screen mode on your laptop. Walk back two or three metres and look at each slide. Can you read every word comfortably? If you’re squinting, your audience at the back of a room will be too.

The thumbnail test

Look at your slides in your software’s thumbnail or grid view, where each slide is small. Text you can still roughly make out at that size will be readable in most rooms. Text that’s just grey lines may be too small.

The real-room test

If you can, open your deck on the actual screen or projector you’ll use, ideally a day before. Sit in the back row and click through.

For video calls, share your screen with a friend viewing in a normal-sized window and ask which slides were hard to read.

A quick checklist

• Titles between about 32 and 44 pt
• Body text 24 pt or larger
• Chart labels 18 pt or larger
• No automatic text shrinking on any slide
• Same sizes for the same text type on every slide
• Clear, regular-weight fonts
• Distance test passed

For a fuller self-check across clarity, structure and design too, try a presentation rubric to grade your own slides.

The short version

Start with titles at 32 to 44 pt, body text at 24 pt or above and chart labels no smaller than 18 pt. If something doesn’t fit, cut it rather than shrink it. Then stand back and test.