Compare real sizes by eye

What this site is

Size Comparison Game is an independent browser game about judging the scale of real objects. In each question, one object stays fixed while you resize another on the same scale. Submit your guess to reveal the measured size, your error and your score. You can start today’s five questions on the home page, play more rounds in practice, or revisit an available day in the archive.

Measurements and drawings

Questions identify the dimension being compared, such as height, length, diameter or wingspan. An object may have a specific model or a published size range; those details matter more than its name alone. The game uses its recorded measurements to set the size of each outline. It does not derive real dimensions from the drawing’s pixels.

After each answer, open View source & measurement to see the source, measurement definition and artwork credit for that pair. If a measurement or illustration needs correction, please tell us which question you saw and which source supports the correction.

How scoring works

Each question is worth up to 100 points. The score is round(100 × min(guess ÷ actual, actual ÷ guess)), so a guess at half or twice the actual size earns 50 points. Five questions total at most 500 points. If the published measurement is a range, guesses inside it earn 100 points; outside it, the nearest boundary is used.

Daily and local records

Everyone gets the same five daily questions for a UTC date. Practice has no round limit. Your first completed daily score, practice progress and best score are saved in this browser when storage is available. There is no account or online leaderboard, and records do not sync between devices.