1 Compare
The black cut-out on sizeitup is already true to scale. Its measurement stays on the label, and everything you do is relative to that reference.
How a sizeitup round works
2 Resize
Slide across the sizeitup board, drag the white silhouette, or use the arrow keys until it looks right beside the black reference. Zoom out when the thing is huge.
3 Lock in
Lock in on sizeitup and the true outline lands in red over your guess, with the real number and the points. Later rounds count more. A perfect day is 1,000.
Three ways to play
Daily
On sizeitup everyone gets the same five pairs, refreshed at midnight in your own time zone. Finish all five to keep a streak.
Unlimited
There is no daily cap on sizeitup. Random pairs come from the whole library, for as long as you want to practise.
Geography
Countries and states appear on sizeitup as cut-outs. You compare the longest extent, or the area, depending on which pair is drawn.
Sizes that catch people out
The number in your head is usually a picture, not a measurement. These three sizeitup pairs live in the library for anyone to try.
blue whale / school bus
27 m long
12 m long
blue whale is 2.3× school bus
Eiffel Tower / Statue of Liberty
330 m tall
93 m tall
Eiffel Tower is 3.5× Statue of Liberty
Texas / France
695,662 km² in area
551,695 km² in area
Texas is 1.3× France
Why a reference, not a number
You are not asked to type a length on sizeitup. You are asked to make two things look right together, which is how the eye already works. The sizeitup board just checks that eye against the tape. Within 6% scores 100. Half the size and double the size both score 45. Five times off scores nothing.
What the board is grading
The black shape is already the true size. The white shape is the guess. After you lock in, the true outline is drawn in red on the same scale. The points follow the ratio between those two shapes, not how famous the object is and not how large it felt in a cropped picture. Half the true size and twice the true size are the same kind of miss. Within 6 percent scores 100. A ratio of two scores 45. Five times off scores 0. On a five-round day the later rounds count more: the weights are one, one, two, three, and three.
The library uses rounded public figures, and the line under the reveal says which version you measured. A large adult blue whale here is 27 metres long. A full-size school bus is 12 metres, bumper to bumper, so the whale is 2.25 buses, not a vague few. The Statue of Liberty is about 93 metres from the ground to the torch, and that figure includes the pedestal. The Eiffel Tower is about 330 metres to the tips of the antennas, about 3.55 of those statues, not a tie between two famous pictures. Texas is a land area of about 696 thousand square kilometres. Metropolitan France is about 552 thousand. Texas is larger. It is not twice France.
Length and area never share a round. Area drawings are shrunk by a square root so both shapes fit on the board, but the printed ratio and the score still use the areas themselves. A picture that looks only a little wider can be a much larger area. The notes linked below take one comparison at a time: the version, the axis, and the multiple. They do not open today's answers. A perfect five is 1,000. Unlimited practice does not use those weights and does not touch the streak.
Notes on the measurements
The score is a ratio. These notes name the version on the board and the multiple that version actually is, so a weighted round is not spent on a postcard.
Questions
Is the daily sizeitup board the same for everyone?
Yes. The five sizeitup pairs are picked from the date in your time zone, so friends on the same day share one puzzle.
How is the score calculated?
By ratio, so a sizeitup guess that is half the size scores the same as one that is double. Within 6% is 100. Half or double is 45. Five times off is 0. On sizeitup, rounds 1 and 2 count once, round 3 counts double, and rounds 4 and 5 count triple.
Do I need an account?
No account is required to play. The streak and today's sizeitup result stay in this browser, and nothing is sent to a server.
Where do the measurements come from?
Rounded public figures: encyclopedias, sports rules, and manufacturer specs. The line under a sizeitup reveal says which version you are looking at — with the pedestal, with the tail, as it stands today.
Can I play in Serbian?
Yes. Choosing SR in the header switches the whole sizeitup site into Serbian, while the daily puzzles themselves stay the same for both languages.