The watt (W) is the SI unit of power, equal to one joule of energy transferred per second.
Watts to Femtowatts
Convert Watt (W) to Femtowatt (fW) instantly with an exact formula, conversion table, and FAQ.
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Convert watts (W) to femtowatts (fW) instantly with formula, conversion table, and FAQ.
Context values
Some unit families need one extra value for a physically accurate result.
A Femtowatt (fW) equals 1e-15 watt(s), a scaled unit of electrical power used for femto-scale electrical work.
fW = W × 1.000000e+15
Results update instantly for Watts to Femtowatts conversions.
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Formula
fW = W × 1.000000e+15
W = fW × 1.000000e-15
Conversion table
| 1 W | 1.000000e+15 fW |
| 5 W | 5.000000e+15 fW |
| 10 W | 1.000000e+16 fW |
| 20 W | 2.000000e+16 fW |
| 50 W | 5.000000e+16 fW |
| 100 W | 1.000000e+17 fW |
| 500 W | 5.000000e+17 fW |
| 1000 W | 1.000000e+18 fW |
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How the formula works
Both watt and femtowatt measure the same physical quantity, so converting between them is a single multiplication. Multiply a value in watts by 1.000000e+15 to get femtowatts. To reverse the conversion, multiply a femtowatt value by 1.000000e-15 to get back to watts.
Frequently asked questions
What is Watt (W)?
The watt (W) is the SI unit of power, equal to one joule of energy transferred per second.
What is Femtowatt (fW)?
A Femtowatt (fW) equals 1e-15 watt(s), a scaled unit of electrical power used for femto-scale electrical work.
How do I convert watts to femtowatts?
Multiply the watt value by 1.000000e+15 to get the equivalent in femtowatts. For example, 5 W × 1.000000e+15 = 5.000000e+15 fW.
Is this conversion exact?
Yes. Both units use fixed, defined scale factors, so the factor 1.000000e+15 is an exact, non-rounded value.
Can I convert femtowatts back to watts?
Yes. Divide the femtowatt value by 1.000000e+15, or multiply it by 1.000000e-15, to get watts.
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About converting watts to femtowatts
The watt (W) is the SI unit of power, equal to one joule of energy transferred per second. A Femtowatt (fW) equals 1e-15 watt(s), a scaled unit of electrical power used for femto-scale electrical work.
Use this calculator to move between watts and femtowatts accurately for homework, engineering, billing, or everyday electricity calculations. The Universal Converter uses exact unit factors, so results stay consistent across the site.