Slide count is an output, not an input
"How many slides for a twenty-minute talk" has no answer until you say how long a slide takes. Ten slides can be four minutes or forty. What follows is the whole grid — every slide count against every per-slide pacing, 60 pairings, all of them at 140 wpm — the speaking rate is fixed here, because on this page the variable is the deck.
| Slides | 0.5 min/slide | 1 min/slide | 1.5 min/slide | 2 min/slide | 2.5 min/slide | 3 min/slide |
|---|---|---|---|---|---|---|
| 5 | 2:30 350 words | 5:00 700 words | 7:30 1,050 words | 10:00 1,400 words | 12:30 1,750 words | 15:00 2,100 words |
| 8 | 4:00 560 words | 8:00 1,120 words | 12:00 1,680 words | 16:00 2,240 words | 20:00 2,800 words | 24:00 3,360 words |
| 10 | 5:00 700 words | 10:00 1,400 words | 15:00 2,100 words | 20:00 2,800 words | 25:00 3,500 words | 30:00 4,200 words |
| 12 | 6:00 840 words | 12:00 1,680 words | 18:00 2,520 words | 24:00 3,360 words | 30:00 4,200 words | 36:00 5,040 words |
| 15 | 7:30 1,050 words | 15:00 2,100 words | 22:30 3,150 words | 30:00 4,200 words | 37:30 5,250 words | 45:00 6,300 words |
| 18 | 9:00 1,260 words | 18:00 2,520 words | 27:00 3,780 words | 36:00 5,040 words | 45:00 6,300 words | 54:00 7,560 words |
| 20 | 10:00 1,400 words | 20:00 2,800 words | 30:00 4,200 words | 40:00 5,600 words | 50:00 7,000 words | 1:00:00 8,400 words |
| 25 | 12:30 1,750 words | 25:00 3,500 words | 37:30 5,250 words | 50:00 7,000 words | 1:02:30 8,750 words | 1:15:00 10,500 words |
| 30 | 15:00 2,100 words | 30:00 4,200 words | 45:00 6,300 words | 1:00:00 8,400 words | 1:15:00 10,500 words | 1:30:00 12,600 words |
| 40 | 20:00 2,800 words | 40:00 5,600 words | 1:00:00 8,400 words | 1:20:00 11,200 words | 1:40:00 14,000 words | 2:00:00 16,800 words |
Bold figure is the running time; the second line is the total spoken word budget at
140 wpm, the deliberate preset. Every cell is
slides × minutes-per-slide, converted with the same function the
calculator uses.
Working backwards from the slot
More often the slot is fixed and the deck is not. This table starts from the time you have been given and derives the rest at the deliberate pace.
| Slot | Slides at 2 min each | Slides at 1 min each | Spoken words |
|---|---|---|---|
| 5 minutes | 3 | 5 | 700 |
| 10 minutes | 5 | 10 | 1,400 |
| 15 minutes | 8 | 15 | 2,100 |
| 20 minutes | 10 | 20 | 2,800 |
| 30 minutes | 15 | 30 | 4,200 |
| 45 minutes | 23 | 45 | 6,300 |
| 60 minutes | 30 | 60 | 8,400 |
The word budget is the part people skip
Deck size gets all the attention and the word budget decides whether you finish. A twenty-minute talk at 140 wpm is 2,800 spoken words whether it has eight slides or thirty. If your speaker notes hold twice that, no amount of slide reorganisation will save you — the talk is simply too long, and the overrun was decided at your desk, long before you reached the stage.
Per slide, the arithmetic is small enough to hold in your head: 140 words a minute, so a slide you intend to spend ninety seconds on carries about 210 spoken words. Write the notes to that and the rehearsal confirms the plan instead of demolishing it.
Why this page uses the slower preset
The default here is 140 wpm, below the site's median of 165, and the reason is structural. Our Presentation preset is the 10th percentile of the 39 talks we measured — the deliberate end of real delivery. Slide-driven talks spend time on things a continuous speech does not: the transition, the beat while the room reads a chart, the glance back to check the slide advanced. None of that produces words, and all of it consumes the slot.
It is a default, not a finding. We measured conference talks without recording whether each one used slides, so we did not measure slide-driven and slide-free delivery as separate populations and cannot tell you the difference between them. If you want a number that reflects your own deck, the meter below measures you reading your own speaker notes — which is both more specific and more honest than any preset we could offer.
A rehearsal routine that catches overruns early
- Convert the slot to words first, before writing notes. For a twenty-minute slot that is 2,800 words at this page's default pace.
- Subtract anything that is not you talking — a video, a demo, questions, the introduction. Convert only what remains.
- Divide by slides to get a per-slide budget, then write notes to that budget from the first draft.
- Rehearse the first two slides separately. Openings run fast, and an opening that outruns its budget compresses everything behind it.
- Time a full run against a countdown you can see without looking down. A drift-free timer is the honest test.
If your slot is one of the common ones, the length pages have the word targets already worked out: five minutes, ten minutes, or the length pages if you are starting from a finished script — 1,000 words and 2,000 words.