Gixo Lumen · slide guide
Big Number Slide
A big number slide shows one figure large enough to dominate the slide. It works because a single number is remembered when a table is not — and it fails when the number arrives with no context, because a figure nobody can compare to anything means nothing.
Last reviewed: August 2026
What belongs on it
- One number. Two numbers on a big-number slide is a stats slide, and neither will be remembered.
- A label that says what it measures. '31%' alone is a Rorschach test.
- A comparison. Against plan, against last year, against the alternative. A number with nothing to compare to has no meaning.
- The source. Small, underneath. Cheap to add and expensive to lack when challenged.
- An implication line. One sentence saying why this number matters.
Getting it right
| Weak version | Stronger version |
|---|---|
| 31% | 31% of new customers leave within 90 days |
| A number with no baseline | 31%, against 12% last year |
| Three numbers competing | One number, two supporting details |
| No source | Source and date in small type beneath |
| Number as the conclusion | Number plus what it means for us |
Common mistakes
- No comparison. The single most common failure — the audience cannot tell whether it is good or bad.
- Precision theatre. 31.47% implies accuracy the underlying data rarely supports.
- Using it for a small number. If the figure is not striking, the format oversells it and the audience notices.
- Repeating it every slide. The effect depends on scarcity; one or two per deck.
- No source. The bigger the number on screen, the more likely someone asks where it came from.
Frequently asked questions
What is a big number slide?
A slide where one figure is shown large enough to dominate, with a short label, a comparison and its source. It is used when a single number carries the argument.
What should go on a big number slide?
One number, a label saying what it measures, something to compare it against, the source, and one line on why it matters.
When should I not use one?
When the number is not striking, when you have several numbers of equal importance, or when the figure needs caveats that will not fit.
How many big number slides should a deck have?
One or two. The format works through contrast with the rest of the deck, so repeating it removes the effect.
What Lumen layout do I use?
The BigNumber layout. Add it to a blank deck, which is free and unlimited on every plan.
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