💥 Car Crash Impact Calculator
Estimate the average force and deceleration experienced in a collision based on vehicle mass, speed, and stopping distance.
How is impact force estimated?
This calculator uses the work-energy theorem: the kinetic energy a vehicle carries must be absorbed over the distance it takes to stop, whether that’s braking distance or the crumple zone collapsing in a crash.
The formula
Kinetic energy is KE = ½mv2. Assuming that energy is absorbed fairly evenly over the stopping distance, average force is Force = KE ÷ distance, and average deceleration is Force ÷ mass, shown here in multiples of g.
Real crashes rarely decelerate at a perfectly constant rate, so this gives an average estimate, not a precise peak force. It’s intended for general physics education and planning discussions, not for accident reconstruction or engineering safety certification.