Energy Calculator
Total mechanical energy is the sum of an object's kinetic energy (from motion) and potential energy (from height) — this splits both out so you can see exactly where the total comes from.
Inputs
Result
198.1 J total
Kinetic 100 J · Potential 98.1 J
How the energy calculator works
Kinetic energy: KE = ½mv².
Potential energy: PE = mgh, using standard gravity g = 9.81 m/s².
Total mechanical energy = KE + PE.
Worked example: 2 kg object moving at 10 m/s, 5 m above ground
- KE = 0.5 × 2 × 10² = 100 J.
- PE = 2 × 9.81 × 5 = 98.1 J.
- Total = 100 + 98.1 = 198.1 J.
Common mistakes to avoid
Forgetting this uses fixed standard gravity
This calculator always uses 9.81 m/s² for the potential-energy term — if working on a different planet or wanting a custom gravity value, use the standalone Potential Energy Calculator, which lets gravity be entered directly.
Assuming total mechanical energy always stays exactly the same as an object moves
In an idealised, friction-free system, total mechanical energy is conserved — kinetic and potential trade off as height and speed change, but real systems lose some energy to air resistance and friction along the way.
Frequently asked questions
Why does total energy stay constant as an object rises or falls (ideally)?
As height increases, potential energy rises and kinetic energy falls (the object slows), and vice versa — the two trade off so their sum remains constant, assuming no energy is lost to friction or air resistance.
What happens to the total when velocity is zero?
All the mechanical energy is potential — this is the situation for an object momentarily at rest at the top of its trajectory, like a ball thrown straight up at its peak.
Can total mechanical energy be negative?
Not in this everyday context — both KE (½mv², always non-negative since v² can't be negative) and PE relative to a ground reference (using positive height) are non-negative here.
How is this different from just using the Kinetic and Potential Energy calculators separately?
This tool adds the convenience of combining both in one step and showing the total, which is useful for problems that specifically ask for total mechanical energy at a given moment.
Related calculators
Kinetic Energy Calculator
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Potential Energy Calculator
Gravitational potential energy at a height.
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Momentum Calculator
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Velocity Calculator
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