Size It Up: how to play and score each round

Choose Size It Up Daily or Unlimited

Daily gives every player the same five-round challenge for that calendar day. Unlimited creates a fresh five-round game whenever you want to keep practising.

Both modes use the same object library, fixed-reference board and 0–100 scoring curve. A finished set totals five rounds and at most 500 points. Unlimited means there is no daily cap, not that every set has an infinite number of rounds. The pool is finite, so an object can reappear in a later set, but targets do not repeat within one five-round run.

Your personal best is saved locally in this browser. It may disappear if you clear site data or switch devices; no account is required. The challenge-board scores are preset milestones, not verified records from other players. Play the shared daily set when you want the same questions as everyone else, and use Unlimited when you want another practice run immediately.

Size It Up scoring: what does each guess earn?

A perfect estimate earns 100 points. Your score falls as the proportional error grows, and guessing twice the true size is treated the same as guessing half the true size.

Size It Up compares the larger of two ratios: your guess divided by the true size, or the true size divided by your guess. This is why guessing 10 m for a 5 m answer is equivalent to guessing 2.5 m. Both are a factor of two away. Between the thresholds below, the score changes smoothly rather than jumping all at once. The displayed percentage error describes your submitted value relative to the actual value; the symmetric factor determines the points.

Five tips for a sharper Size It Up estimate

• Start with the labelled reference and estimate how many times it fits along the mystery object's dimension.
• Use a familiar anchor, such as a person at 1.7 metres or a school bus around 12 metres, before adjusting the final scale.
• Read the dimension label first: wingspan and body length can give very different answers for the same animal.
• Zoom the board when a target is unusually tiny or large. Zoom changes the view, not the answer or the fixed reference.
• After each reveal, identify why you missed before moving on; a good correction is more useful than memorising one number.

What are the challenge scores?

Rookie Target, Sharp Eye and Scale Master are preset milestones, not live player accounts or a global leaderboard.

They give every new player a useful target from the first game. A real public leaderboard would require server-verified scores and would be shown separately.

What should I look at before moving the object?

The first rule of how to play Size It Up is to begin with the words beside the reference, not the picture alone. A round may ask for an animal's body length, a bird's wingspan, a sculpture's height or a ship's bow-to-stern length. These are different physical axes. A bird with folded wings might look small in a photograph while its fully spread wings occupy several metres. Reading the axis first prevents a visually plausible but mathematically unrelated guess.

Next find a ratio you can picture. If the target looks about twice the reference's measured dimension, begin near twice the reference value. The reference is fixed while you adjust only the coloured target. You can use the ruler and grid to check the scale, but neither replaces judging which endpoints the measurement actually connects. A good estimate is a statement about a defined dimension, not a judgement about how much area a shape fills on the screen.

What happens after I lock in a size?

The game preserves the size you submitted and draws the true outline at the same origin. That makes the gap between your estimate and the answer visible without changing the reference object. The ruler identifies both positions, and the result panel reports the actual measurement, your submitted measurement and the proportional error. If the outlines overlap closely, you were close; if they separate widely, use the direction of the difference before moving on.

A reveal is also a small learning exercise in how to play Size It Up more accurately next time. Ask whether you chose the wrong dimension, misread the reference or simply lacked a familiar anchor. Those are different mistakes. An albatross wingspan is not its body length; a monument may include or exclude its base; an ocean animal photographed without a diver may have no useful depth cue. The source note on each object guide explains the exact number used by the game so you can inspect the answer rather than memorise it blindly.

Why does a ratio-based score matter?

A fixed metre penalty would behave badly across this library. Missing a tiny animal by one metre is enormous, while missing a very large tower by one metre is barely noticeable. Size It Up therefore compares your estimate with the actual value proportionally. The same multiplicative mistake has the same meaning at any scale. This lets a millimetre-sized spider and a hundreds-of-metres-tall structure appear in the same five-round game without making one category inherently easier to score.

The round score is a guide to accuracy, not a scientific uncertainty statement. Some natural measurements vary between individuals and some prehistoric measurements are estimates. Where the underlying value is a range, the guide says which representative, maximum or documented measurement was chosen. Use the score to compare attempts under the game's published rules; use the source and measurement note to understand the real-world limits of the number.

Can I use Size It Up on a phone?

Yes. The daily and unlimited games run in a mobile browser. Drag the target silhouette to change its scale, or use the plus and minus controls for smaller adjustments. The reference silhouette stays at a fixed size. If you need a closer look at an unusually small object, use the board zoom controls; zoom changes the view, not the real-world answer. The same five-round scoring rules apply on desktop and mobile.

Your local progress is tied to this browser and device. Clearing site storage, changing browsers or using private mode may remove a saved best score. There is no account requirement and the preset challenge scores are milestones, not names of live competitors. When you finish a daily set, unlimited mode offers more varied practice without waiting for the next daily puzzle.