Einstein's theory of relativity encompasses both special relativity and general relativity. Together these describe the structure of spacetime including insights into energy, gravitation and time dilation. Wolfram|Alpha includes numerous formulas and tools for calculating the effects of relativistic motion, gravitational distortion and other effects of relativity.

Special Relativity

Compute the effects of special relativity on length, time and other physical properties.

Compute relativistic length contraction:

Determine the time dilation felt by probes and satellites:

Do relativistic addition of velocities:

Determine relativistic aberration:

Determine proper velocity:

Compute relativistic momentum:

Calculate the rest energy of an object:

General Relativity

Use general relativity to calculate time dilation and the properties of black holes.

Determine gravitational time dilation near massive objects:

Compute the properties of black holes: