RULES · SCORING · TIPS
How to play Size It Up
Two silhouettes on a table. One is the truth, one is yours. Make yours the right size. That is the whole of Size It Up — the rest of this page is the detail that turns a guess into a skill.
The three steps
- Compare. The black silhouette on the left of the Size It Up board is the reference. It is drawn at true scale, with a ruler above it showing its real measurement, and it never moves. Everything you do is relative to it.
- Resize. Drag the white silhouette anywhere on the board. Pull any corner or edge of its frame — or pinch on a phone, or scroll the mouse wheel over it — until it looks right next to the reference. The side you are not pulling stays put, so the cut-out never jumps. Zoom the board out if what you are sizing is enormous; the reference stays where it is while you make room.
- Lock in. The true size is drawn in red over your guess, with the real number, how far off you were, and a fact worth repeating. Then the next round. Five rounds make a day.
The dotted line shows which dimension is being compared: length for a whale or a bus, height for a tower or a giraffe. Only that dimension counts, so a whale that is the right length but drawn too fat still scores full marks — the silhouette keeps its own proportions whatever you do to it.
How the Size It Up score works
Each round is worth up to 100 points, so a perfect day is 500. Points depend on how far your size is from the true size, and the curve is steep near the top on purpose: being close is rewarded, being roughly right is not, and being wildly wrong costs about the same as being merely wrong. The table is the whole rule.
| Your guess is | Points |
|---|---|
| Within 6% | 100 |
| Within 12% | 90 |
| Within 20% | 78 |
| Within 32% | 62 |
| Half or double (2×) | 45 |
| Three times off | 30 |
| Four times off | 18 |
| Five times off or more | 0 |
Between rows the score slides smoothly. The error is measured as a ratio, so guessing half the size and guessing double the size score the same — there is no advantage in always guessing small, which is the habit most people bring from other size games. A 2.3-metre gorilla guessed at 2.0 metres is 13% off and scores about 88; guessed at 4.6 metres it is double and scores 45; guessed at 30 centimetres it is more than five times off and scores nothing, however confident you felt.
Five tips for a sharper eye
- Carry anchors. A school bus is 12 metres, an adult is 1.7, a door is 2, a tennis court is 24, a football pitch is 105, a blue whale is 27. Measure everything against one of them. Size It Up gets much easier the moment you stop thinking in metres and start thinking in buses.
- Count the reference. Ask "how many of the black one fit inside the white one?" — three buses, half a bus, a quarter of a bus. Ratios are easier than metres, and the scoring is in ratios anyway.
- Zoom out early. If the thing you are sizing might be huge — anything with "whale", "tower" or "planet" in its name — zoom out before you start dragging, so you are not fighting the edge of the board while you think.
- Distrust height. Almost everyone makes towers too short and animals too tall. When in doubt, go a little taller on buildings and a little shorter on animals, then check your instinct against the reveal.
- Play unlimited. Twenty rounds of Size It Up Unlimited before the daily puzzle is the fastest way to a better eye. The daily five are the exam; unlimited is the homework.
Streaks, sharing and challenges
Finish all five rounds and the day counts toward your streak; miss a day and it resets. Your streak, your best score and your history live in your browser — there is no account, so there is nothing to sign up for and nothing to lose except by clearing your browser data.
The share card after round five shows your five results as coloured blocks and your total, without the answers, so you can post it before your friends have played. If you would rather dare someone directly, any Size It Up run — the daily five or an unlimited set — can be sent as a challenge link: they get the same silhouettes you got, one attempt each, and the two scores end up side by side, with the day's answers shown to them only after they lock in.
Where the sizes come from
Every object in Size It Up links to the source of its measurement — usually an encyclopedia entry or a manufacturer's specification — and every silhouette is either drawn for this site or taken from a public-domain or CC0 collection; the credits page lists all of them. When a size is genuinely contested, the caption says which version you are looking at: the Statue of Liberty with its pedestal, the Empire State Building to the roof rather than the antenna, an average adult human rather than a tall one.
If you think a number is wrong, you are probably not the first — the corrections address on the credits page reaches a person, and fixes go in the same day.