1. Check the reference
The green object gives you a known height, length, diameter or area.
Back to the gameA LITTLE KNOW-HOW
How to Play Size It Up
No stopwatch. No complicated rules. Just you, two silhouettes, and a sense of scale.
HOW TO PLAY
Controls & scoring Your eye. Two silhouettes. One scale.
2. Make your estimate
Resize the purple silhouette until the two look right together.
3. Reveal the real size
Lock in your guess. See the answer, your points and the source.
What are you estimating?
The green reference is shown at a known height, length, diameter, or map area. Your job is to adjust the purple object to the same real-world scale. Check the dimension in its label: a bus is measured along its length, while a standing giraffe is measured by its height.
Geography questions compare area in square kilometres. Maps use a local equal-area projection: twice the area means about 1.41× the width and height. The Geography topic uses dated UN total surface-area values, rounded as described in each note. Advanced map questions in Explore use approximate areas derived from generalized map outlines. Read the source note to see which definition applies. An area is only compared with another area.
Controls on phone, mouse and keyboard
- Mouse: drag the purple corner handle, move the slider, or use the smaller and larger buttons.
- Touch: use the slider and the large plus and minus buttons. Dragging the handle works too.
- Keyboard: Tab to the slider and use the arrow keys. Home and End move to the range limits. Tab to Lock in and press Enter to submit.
- Board zoom: the plus and minus controls change your view of both objects equally. Fit view brings both silhouettes back into view. Zoom never changes your answer.
The slider represents your target’s measured dimension as a multiple of the reference measurement. Both silhouettes always share the same scale. The camera stays still while you resize. Use Fit to bring both silhouettes into view; this changes the view, not your estimate. The slider runs from 0.05× to 20× the reference measurement.
Lock in your perspective.
Press Lock in my guess when it feels right. The correct silhouette appears in orange, alongside your purple estimate. You’ll see the actual measurement, your error, a short fact, and a link to the measurement source. Each round can only be submitted once.
How scoring works
Each round awards 0–100 points. We use a symmetric ratio-based rule: a guess twice the real size gets the same points as one half the real size.
| Your estimate | Round points |
|---|---|
| Exactly right | 100 |
| 1.1× the real size | 94 |
| 1.5× or ⅔ of the real size | 75 |
| 2× or ½ of the real size | 57 |
| 5× or ⅕ of the real size | 0 |
score = round(100 × max(0, 1 − |ln(estimate / actual)| / ln(5)))
A perfect five-round game earns 500 points. The displayed percentage error uses the actual size as its denominator, so it is directional even though the points are symmetric.
Daily challenge or unlimited practice?
The daily challenge uses a shared set of five comparisons for each UTC date. It resets at midnight UTC. Progress survives a refresh in the same browser when local storage is available. Completed daily games count toward your streak.
Unlimited mode creates another set of five comparisons each time you start a new game. It’s a place to practice, and it doesn’t change your daily statistics. The library is finite, so objects can appear again across games. Recent pairs are avoided where possible. Explore mode lets you choose a theme from the full comparison bank, including countries and regions.
Size It Up collections
Choose a themed collection to play five selected comparisons in a fixed order. Replay to improve your best score. Collection records are separate from daily streaks.
Can I replay a daily puzzle?
Yes. The daily archive lets you replay any challenge published on this site since October 25, 2026. Archive results are practice records and do not replace your first Daily score. Looking for earlier Magnitudle puzzles? Their archive belongs to the original game and is a separate collection.
Scale Streak: a different way to play
Scale Streak is an eight-question challenge with three hearts. Pick bigger or smaller for 100 base points, or choose a precise size estimate before the answer is revealed for 250 base points if you land within 20%. Two consecutive correct answers unlock 2× points on future answers; four unlock 3×. After three total correct answers, pick one perk. A miss costs one heart and normally breaks your combo. Your Classic scores stay separate.
Three ways to sharpen your guesses
- Use an anchor. Picture the reference object in the real world before moving the target.
- Compare the marked dimension. Don’t confuse a vehicle’s length with an animal’s height.
- Read the reveal. Living things vary. The note tells you which representative example you were estimating.