RULES · SCORING · TIPS
How to play Sizekin
Start with a measured reference, choose a proportion, and check the result. This guide explains the controls, the endpoints used for each measurement, and how your estimate becomes a score.
The three steps
- Compare. Find the dark silhouette and read its measurement. That reference stays fixed while you adjust the light target. A useful first question is whether the target should be shorter, about equal, or several times larger.
- Resize. Drag across the board or pull the target handle. The ruler and plus/minus buttons offer another way to adjust; arrow keys work when the board has focus. On a touchscreen, a two-finger pinch changes the guess. The zoom buttons change the viewing scale, not the answer.
- Lock in. Submit when you are satisfied with the proportion. The reveal shows the recorded measurement, your estimate and the points awarded. Continue to the next round after inspecting the difference.
Follow the ruler endpoints and the dimension label. A body length, a standing height and an open wingspan are different measurements even when the silhouettes look similar. Resizing preserves the object's shape; the game scores the marked dimension.
How the Sizekin score works
First, the game converts your size ratio into a base score from 0 to 100. It then multiplies that score by the round weight. Daily uses weights of 1, 1, 2, 3 and 3, for a maximum total of 1,000. The table lists the base-score anchors before those weights are applied.
| Your guess is | Points |
|---|---|
| Within 6% | 100 |
| Within 12% | 90 |
| Within 20% | 78 |
| Within 32% | 62 |
| Half or double (2×) | 45 |
| 3× or 1/3 of the size | 30 |
| 4× or 1/4 of the size | 18 |
| At least 5×, or at most 1/5 of the size | 0 |
The error ratio is the larger of guess ÷ answer and answer ÷ guess. For example, if the selected answer is 1.6 metres, both 0.8 metres and 3.2 metres have an error ratio of 2 and earn 45 base points. Between the table's anchors, points are interpolated on a logarithmic scale and rounded to a whole number. A ratio of at most 1.06 earns 100; a ratio of 5 or more earns zero.
Five tips for a sharper eye
- Remember a reference. Choose one reference whose dimension you can picture clearly. A measured tabletop object may help with small targets; a familiar vehicle may help with larger ones. Keep the unit and the measured direction attached to the number you remember.
- Count the reference. Estimate a multiple before choosing a precise value. One and a half reference lengths, for example, is a more useful starting point than guessing an unrelated number and trying to justify it afterward.
- Zoom out early. If the target approaches the edge of the board, adjust the view with the zoom controls. Keep watching the reference measurement so that a change in screen size does not become a change in your intended ratio.
- Check your assumptions. Use the reveal to check your own assumptions. Was the wrong model in your mind? Did you include an antenna or tail that the measurement excludes? There is no general rule that every animal should be smaller or every building taller.
- Play unlimited. Twenty rounds of Sizekin Unlimited for extra practice in a category, with progress kept separate from your Daily set.
Progress, sharing and challenges
Finish all five rounds to save a Daily result. Your units, unfinished size adjustment and links to saved games stay in your browser; submitted guesses and scores are also held by our server. No account is needed. Clearing browser data removes the identity that connects you to those games. Browse Past Games to revisit available dates; replaying a past day does not replace your Daily result.
The share card after round five shows your five round scores and your total. Save the image on your device or create a public link to share it. If you would rather dare someone directly, a daily or unlimited run can be sent as a challenge link: they get the same silhouettes, submit their own guesses, and see the scores together on the challenge board.
Where the sizes come from
Every object in this edition records the selected measurement and its declared source where available, usually an encyclopedia entry or a manufacturer’s specification. The credits page lists silhouette authors, licences and source links. Some declarations are inherited from the reference catalogue; they are not a claim that we created every silhouette or independently verified every measurement.
When a size has several interpretations, read the version and measurement caption: the Statue of Liberty with its pedestal, a tower to its roof rather than its antenna, or a selected adult animal rather than a record specimen. If you think a number is wrong, use the feedback form and name the object, its displayed size and your source so we can review it.
Explore real proportions in the Size Comparison Game.