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Efficiency calculator
Efficiency calculator
Enter your values below and press Calculate to see your result instantly.
System Efficiency (Ξ·)
75.0%
ENERGY WASTED
250 J
VS BENCHMARK
-20% Below
Your system loses 25% of energy to friction or heat. This is 20% below high-efficiency motors.
About the Efficiency calculator
Efficiency compares the useful output of a system with the energy put in. Use it for motors, engines, lights and other machines.
How to use the Efficiency calculator
- Enter the Total Energy Input and the Useful Work Output in the same unit (joules or watts).
- Optionally choose a System Standard Benchmark to compare against.
- Press Calculate.
Formula and method
Efficiency (%) = Useful output Γ· Total input Γ 100. The rest is lost, mostly as heat.
Worked example
A machine that takes in 1,000 W and delivers 800 W of useful power is 80% efficient.
Tips
- No real machine is 100% efficient.
- Higher efficiency lowers running costs.
Frequently Asked Questions
Good electric motors reach about 90 to 95 percent, while petrol engines are typically 20 to 30 percent.