Alien Civilization Calculator
Classify civilizations on the Kardashev scale, estimate energy budgets, project growth timelines, and explore Dyson sphere parameters.
Free Astronomy Calculators
15 toolsOrbital mechanics, escape velocity, stellar luminosity, and planetary calculators. Browse our free astronomy tools below — no sign-up required.
Drake Equation Calculator
Estimate the number of communicating civilizations in the Milky Way using all seven Drake Equation factors with preset scenarios.
Earth Orbit Calculator
Calculate orbital distances, velocities, perihelion, aphelion, and seasonal solar declination for Earth or any planet.
Exoplanet Calculator
Characterize exoplanets — compute gravity, density, equilibrium temperature, habitability, and compare with known worlds.
Exoplanet Travel Planner Calculator
Plan interstellar journeys — calculate travel times, time dilation effects, energy requirements, and compare speeds for exoplanet destinations.
Gravitational Time Dilation Calculator
Calculate how gravity warps time using general relativity — compare clocks near massive objects, black holes, neutron stars, and Earth.
Hubble's Law Calculator
Calculate recession velocity, distance, and redshift using Hubble's Law. Compare Hubble constant values and explore the expanding universe.
Kepler's Third Law Calculator
Calculate orbital periods, distances, and central masses using Kepler's Third Law with solar system verification and unit conversions.
Length Contraction Calculator
Calculate relativistic length contraction at any fraction of the speed of light with visual comparisons, Lorentz factor tables, and speed references.
Light-Year Calculator
Convert between light-years, parsecs, AU, and km. Calculate light travel times and compare cosmic distances to known objects.
Luminosity Calculator
Calculate stellar luminosity from radius and temperature using the Stefan-Boltzmann law. Includes spectral classification and habitable zone estimates.
Orbital Period Calculator
Calculate the orbital period for any body orbiting a central mass. Includes solar system verification, unit conversions, and binary system mode.
Schwarzschild Radius Calculator
Calculate the event horizon radius of a black hole from its mass. Includes photon sphere, ISCO, Hawking temperature, and famous black hole comparisons.
Time Dilation Calculator
Calculate special relativistic time dilation from velocity. Find the Lorentz factor, dilated time, and compare effects at various speeds from walking to near-light.
Weight on Other Planets Calculator
Calculate your weight on every planet, moon, and dwarf planet in the solar system. Includes gravity comparison chart, jump height estimates, and planetary data.