Efficiency Calculator
🛹 Work, energy & power. Use the Efficiency formula to find efficiency, useful output, total input: pick the value you want, type the others, and the answer updates as you go.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Efficiency | % |
| Useful output | J |
| Total input | J |
Worked example
Find the efficiency when Useful output = 50 J, Total input = 200 J.
Using η = (useful output)/(total input) × 100\%: Efficiency = 25 %.
Frequently asked questions
What is the formula for Efficiency?
η = (useful output)/(total input) × 100\%.
What do the letters stand for, and what units are used?
Efficiency in %, Useful output in J, Total input in J.
How do you calculate efficiency?
Put the values into η = (useful output)/(total input) × 100\%. For example, with Useful output = 50 J, Total input = 200 J, efficiency = 25 %.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (efficiency, useful output, total input) and fill in the others: it rearranges the formula for you.
