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 space shuttle compared with a tennis court?

Use the tennis court as your reference.

01 / 05
Tennis court, reference object for length comparison
Space shuttle, estimated length relative to the tennis court
Tennis courtReference
Space shuttleYour 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 space shuttle compared with a tennis court?

    Tennis court, used for the length comparison
    ReferenceTennis court23.77 m long
    Space shuttle, used for the length comparison
    Compared objectSpace shuttle37.2 m long

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 1.565×

    Space shuttle ÷ Tennis court, comparing length.

    The Space Shuttle orbiter was about 122 feet (37.2 metres) long, measured without its external fuel tank or boosters.

    Measurement source · nasa.gov

  2. Round 2

    How tall is a male ostrich compared with an adult?

    Adult, used for the height comparison
    ReferenceAdult1.7 m tall (representative)
    Male ostrich, used for the height comparison
    Compared objectMale ostrich2.7 m tall (large male)

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 1.588×

    Male ostrich ÷ Adult, comparing height.

    Male ostriches can stand up to about 2.7 metres tall. This round uses that upper height, measured from the feet to the top of the head.

    Measurement source · animals.sandiegozoo.org

  3. Round 3

    How long is a table tennis table compared with a tennis racket?

    Tennis racket, used for the length comparison
    ReferenceTennis racket73.7 cm long (maximum)
    Table tennis table, used for the length comparison
    Compared objectTable tennis table2.74 m long

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 3.718×

    Table tennis table ÷ Tennis racket, comparing length.

    The playing surface of a table tennis table is 2.74 metres long and 1.525 metres wide. The vertical sides of the top are not part of that surface.

    Measurement source · documents.ittf.sport

  4. Round 4

    How long is an orca compared with a blue whale?

    Blue whale, used for the length comparison
    ReferenceBlue whale33.5 m long (maximum)
    Orca, used for the length comparison
    Compared objectOrca9.8 m long (maximum)

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 0.2925×

    Orca ÷ Blue whale, comparing length.

    Killer whales reach up to 32 feet (9.8 metres). This round uses that upper length.

    Measurement source · fisheries.noaa.gov

  5. Round 5

    How long is a basketball court compared with a space station?

    Space station, used for the length comparison
    ReferenceSpace station109 m long (end to end)
    Basketball court, used for the length comparison
    Compared objectBasketball court28 m long

    Illustrations shown individually, not to a shared scale.

    Actual size ratio

    ≈ 0.2569×

    Basketball court ÷ Space station, comparing length.

    A basketball court is 28 metres long and 15 metres wide, measured from the inner edge of the boundary line. This silhouette spans that length.

    Measurement source · assets.fiba.basketball
All past challengesPlay today’s challenge