Free Relativistic Mass Calculator
Calculate the relativistic (apparent) mass of an object: m_rel = m0 * gamma = m0 / sqrt(1 - v^2/c^2).
kg
m/s
Relativistic Mass
2.293433 kg
Mass Increase (%)129.3433 %
Relativistic Mass vs Rest Mass (m0)
Relativistic Mass
As an object approaches the speed of light, its inertia increases, making further acceleration progressively harder.
Formula
m_rel = m0 * gamma = m0 / sqrt(1 - v^2/c^2)
Note: Modern physics prefers the concept of invariant (rest) mass. The "relativistic mass" is the total energy divided by c^2, but it is a useful pedagogical tool.
Example Calculation
1 kg object at 0.9c.
- 01gamma = 1 / sqrt(1 - 0.81) = 2.294
- 02m_rel = 1 * 2.294 = 2.294 kg
- 03Mass appears 129.4% larger.
Frequently Asked Questions
Learn More
Understanding Newton's Laws of Motion
A comprehensive guide to Newton's three laws of motion. Learn about inertia, force and acceleration, action-reaction pairs, and how these principles govern everyday physics.