How long should you spend on each slide?

The short answer: plan for one to two minutes per content slide. A 10-minute talk usually works with 6–10 slides, a 20-minute talk with 12–18. But the average hides the real problem. Most presentations don't run over because there are too many slides – they run over because two or three slides quietly take three times longer than planned.

Start from the time limit, not from the slides

Take your total time and subtract one minute for the opening and one for the ending. Divide the rest by the number of content slides. That's your time budget per slide. With 15 minutes and 11 content slides, you have a little over a minute each.

Not every slide deserves the same time. A title slide, an agenda or a section divider needs 10–20 seconds. A chart with the key result of your work may need three minutes. Move time from the simple slides to the important ones – but do it on purpose, not by accident.

Typical times by slide type

• Title and agenda: 15–30 seconds each.
• Text slide with 3 bullet points: about 1 minute.
• Chart or diagram: 1.5–3 minutes – explain what the audience should look at first.
• Image or quote: 20–60 seconds.
• Summary: 1 minute.
• Questions: whatever time is left – plan at least 2–3 minutes if the format allows it.

Why you can't estimate it in your head

When you click through your slides silently, every slide feels short. Speaking out loud takes roughly twice as long as thinking the same sentences. Add a question from the audience and an example you didn't plan, and a "one minute" slide becomes three. The only reliable way to know is to rehearse out loud and measure.

How to measure your time per slide

1. Open your slides in a timer that records each slide separately – a stopwatch only tells you the total.
2. Enter your time limit so every slide gets a budget.
3. Present out loud, exactly as you would in front of people.
4. Afterwards, look at the slides that went over their budget. Those are the ones to shorten or split.
5. Repeat. Your second run is usually 10–20 % shorter.

SlideTimer does this for free: upload your PowerPoint or PDF, set a target duration and it shows the time for every slide, highlights the ones that ran over and keeps a history of your runs.

What to do with a slide that takes too long

• Cut the detail you only say "for completeness". If nobody asks, nobody misses it.
• Split it into two slides with one message each – it often gets faster, not slower.
• Move the detail to the appendix and show it only if someone asks.
• Write the one sentence the slide must deliver and start with it.

A quick example

A student has 10 minutes for a thesis presentation with 12 slides. Budget: 2 minutes for opening and ending, so 8 minutes for 10 content slides – 48 seconds each. The first rehearsal takes 14 minutes. The per-slide view shows that the method slide took 3:40 and the results chart 2:50. Cutting the method slide to the three decisions that matter brings the next run to 10:30, the third to 9:45.