Astronomy Calculators

Free astronomy calculators for planets, stars, and cosmic distances — explore the universe from your browser. No signup required.

About these astronomy calculators

These astronomy tools put cosmic scales in human terms. Find how your weight changes as surface gravity varies across the planets — from the crushing pull of Jupiter to the gentle tug of Mars. Convert vast distances between light years, astronomical units, and parsecs with context about what each unit represents in practice.

Every tool runs entirely in your browser with no signup required. Whether you're a student exploring orbital mechanics, an amateur astronomer planning a night's observation, or simply curious about the universe — these calculators are ready immediately.