How to play Sizeroo, the daily size guessing game

Each day Sizeroo gives you 5 real things, from a grain of rice to the distance to the Moon. Slide along the scale (or use ÷2, −, + and ×2) to the size you think each one is, then lock it in to see the real size, a short fact and how many kangaroos it would take to match it.

The scale grows by ten at every rung, so being off by a few metres matters for a bus but not for a mountain. Scoring is by ratio: within 10% scores 100 points, twice too big or too small scores about 70, and 10 times off scores 0. The best possible score is 500.

FAQ

Is Sizeroo free?

Yes. Sizeroo is free to play in your browser, with no account or download. Your streak and best score are saved on your own device.

Is everyone's puzzle the same?

Yes. Everyone gets the same 5 things on the same date, so you can compare scores with friends.

Is Sizeroo like Size It Up?

If you enjoy size guessing games such as Size It Up on Magnitudle, Sizeroo is another daily size game to try. It is an independent game made by Guessroo and is not affiliated with Magnitudle. Instead of comparing two pictures, you place your guess on one scale that runs from 0.01 mm to a million kilometres.

What kinds of questions are there?

How tall is the Eiffel Tower? How long is a blue whale? How wide is the Moon? How thick is a human hair? Every day mixes tiny things, everyday objects, animals, buildings, landmarks and planets, so it works as a size quiz, an estimation game and a quick science warm-up.

Why kangaroos?

Guessroo's mascot is a kangaroo. A red kangaroo stands about 1.5 metres tall and can cover about 8 metres in one hop, so every answer is also shown in roos or hops.

I think a size is wrong.

Many real things vary, so we use a typical or official figure. Tell us at [email protected] and we will check it.