Free · Big and small worlds

Exoplanet Size Comparer for Kids

Put two exoplanets side by side and see how their sizes compare with Earth.

  • Clear, kid-friendly steps
  • Private in your browser
  • No signup

Worlds beyond our Sun

Put two faraway worlds side by side

Size comparison

How big are they?

TRAPPIST-1 e0.91 Earth radii
Kepler-452 b1.67 Earth radii

Powered by Open Exoplanet Catalogue (curated subset), an open-source library available under MIT.

Three simple steps

How to use it

  1. Pick a real planet that circles a star beyond our Sun.
  2. Compare its size, year, heat, distance, or discovery date.
  3. Try another world and see how different it can be.

Private by default

Your words and choices stay in this browser tab. There are no accounts, uploads, ads, or trackers inside the tool. Close the tab and the working data is gone.