size it up.

A little perspective

Trust your eye.

Five comparisons. Two objects each time. How close can you get?

  1. Compare

    The object on the left is your measuring stick. Keep resizing — the view automatically zooms out when you need more room. You can also zoom the canvas; both objects scale together without changing your estimate.

  2. Find the right size

    Drag the blue handle, scroll while hovering it, tap − / +, or use the arrow keys. Match the dimension in the question.

  3. Lock it in

    Reveal the real size and earn up to 100 points. Five rounds add up to a maximum of 500.

The first answer in each round counts. A new challenge arrives every day at 00:00 UTC. Object sizes use the specific examples shown in the answer.

Read the full rules and scoring guide
Practice · not ranked
All past challenges

How long is a humpback whale compared with a blue whale?

Use the blue whale as your reference.

01 / 05
Blue whale, reference object for length comparison
Humpback whale, estimated length relative to the blue whale
Blue whaleReference
Humpback whaleYour estimate
Fine tune
All past challenges
View answers and sources

Answers from this past challenge. Today’s challenge remains a surprise.

  1. Round 1

    How long is a humpback whale compared with a blue whale?

    Blue whale, used for the length comparison
    ReferenceBlue whale33.5 m long (maximum)
    Humpback whale, used for the length comparison
    Compared objectHumpback whale18 m long (maximum)

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 0.5373×

    Humpback whale ÷ Blue whale, comparing length.

    Humpback whales reach up to about 60 feet (18 metres). This round uses that upper length, not a typical adult.

    Measurement source · fisheries.noaa.gov

  2. Round 2

    How long is a baseball compared with a basketball?

    Basketball, used for the length comparison
    ReferenceBasketball24.2 cm diameter (size 7, representative)
    Baseball, used for the length comparison
    Compared objectBaseball7.4 cm across (representative)

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 0.3058×

    Baseball ÷ Basketball, comparing length.

    MLB rules allow a circumference of 9 to 9¼ inches. This round uses a representative 7.4-centimetre diameter, rounded from the midpoint circumference divided by pi.

    Measurement source · mktg.mlbstatic.com

  3. Round 3

    How long is an American alligator compared with an orca?

    Orca, used for the length comparison
    ReferenceOrca9.8 m long (maximum)
    American alligator, used for the length comparison
    Compared objectAmerican alligator3.4 m long (average adult male)

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 0.3469×

    American alligator ÷ Orca, comparing length.

    Adult male American alligators average about 3.4 metres in length. This round measures the whole animal from its snout to its tail tip.

    Measurement source · nationalzoo.si.edu

  4. Round 4

    How long is a Komodo dragon compared with a white shark?

    White shark, used for the length comparison
    ReferenceWhite shark6.1 m long (maximum)
    Komodo dragon, used for the length comparison
    Compared objectKomodo dragon3.13 m long (verified maximum)

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 0.5131×

    Komodo dragon ÷ White shark, comparing length.

    The largest verified Komodo dragon was 3.13 metres long. This round uses that record length from the snout to the tip of the tail.

    Measurement source · nationalzoo.si.edu

  5. Round 5

    How long is a soccer pitch compared with a space shuttle?

    Space shuttle, used for the length comparison
    ReferenceSpace shuttle37.2 m long
    Soccer pitch, used for the length comparison
    Compared objectSoccer pitch105 m long (international, representative)

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 2.823×

    Soccer pitch ÷ Space shuttle, comparing length.

    International matches set the touchline between 100 and 110 metres. This round uses 105 metres, the middle of that range.

    Measurement source · theifab.com
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