Femtonewton is 1e-15 newton units.
Femtonewtons to Kilogram-forces Converter — fN to kgf
Convert Femtonewton (fN) to Kilogram-force (kgf) using the exact conversion factor (1 femtonewton = 1.019716e-16 kilogram-force). See the formula, worked examples, conversion table, and common uses.
Femtonewtons to Kilogram-forces converter
Converter
Force Converter
Convert newtons, dynes, pound-force, kilogram-force, kips, and ounce-force.
Context values
Some unit families need one extra value for a physically accurate result.
Kilogram-force under standard gravity.
Result = input x 1e-15 / 9.80665.
Force uses the newton as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Femtonewtons to Kilogram-forces
Femtonewton and Kilogram-force both measure force, and the conversion matters whenever an SI-trained engineer needs to compare notes with a US-trained one, or vice versa. Specifically: Femtonewton is 1e-15 newton units, and kilogram-force under standard gravity.
Formula
kilogram-forces = femtonewtons × 1.019716e-16
This factor comes from each unit's defined relationship to the category's base unit: 1 femtonewton equals 1e-15 base units, and 1 kilogram-force equals 9.80665 base units, so dividing one by the other gives the direct femtonewton-to-kilogram-force factor of 1.019716e-16.
Simple example
1 fN × 1.019716e-16 = 1.019716e-16 kgf
1 femtonewton = 1.019716e-16 kilogram-forces.
Real-world example
10 fN × 1.019716e-16 = 1.019716e-15 kgf
10 femtonewtons = 1.019716e-15 kilogram-forces.
Conversion table
| Femtonewton (fN) | Kilogram-force (kgf) |
|---|---|
| 1 fN | 1.019716e-16 kgf |
| 5 fN | 5.098581e-16 kgf |
| 10 fN | 1.019716e-15 kgf |
| 50 fN | 5.098581e-15 kgf |
| 100 fN | 1.019716e-14 kgf |
| 1,000 fN | 1.019716e-13 kgf |
Reverse conversion: Kilogram-force to Femtonewton
1.019716e-16 kgf × 9.80665e+15 = 0.9999997911 fN
1.019716e-16 kilogram-forces = 0.9999997911 femtonewtons.
femtonewtons = kilogram-forces × 9.80665e+15
For a page dedicated to this direction, see Kilogram-force to Femtonewton.
Understanding the Femtonewton (fN)
Femtonewton is 1e-15 newton units.
Understanding the Kilogram-force
Kilogram-force (kgf) measures force. Defined as the force exerted by standard gravity on a mass of one kilogram — exactly 9.80665 newtons. It is classified as a non-SI unit, deprecated but still encountered.
Where it's used: Still encountered in some older European and Asian engineering specifications and torque-related equipment, though official use has been phased out in favor of the newton
Kilogram-force vs. newton. The newton is the modern SI unit of force; kilogram-force is an older, gravity-dependent unit still occasionally seen on legacy equipment. 1 kgf equals exactly 9.80665 N.
Uses of the Kilogram-force today
- Appears on some older or legacy engineering and mechanical specifications, particularly torque wrenches and spring-force ratings, predating wider adoption of the newton
Kilogram-force — sources
- BIPM SI Brochure — Notes kilogram-force among non-SI force units whose use is discouraged in favor of the newton.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many kilogram-forces are in 1 femtonewton?
1 femtonewton equals 1.019716e-16 kilogram-forces, using the exact defined conversion factor rather than an estimate.
How do I convert femtonewton to kilogram-force?
Multiply the femtonewton value by 1.019716e-16. The converter above does this instantly to whatever precision you set.
How do I convert kilogram-force back to femtonewton?
Use the reverse factor: 1 kilogram-force equals 9.80665e+15 femtonewtons. You can also use the swap control in the converter above to flip the direction instantly.
What is a femtonewton?
Femtonewton (fN) is a unit of force.
What is a kilogram-force?
Kilogram-force (kgf) measures force. Defined as the force exerted by standard gravity on a mass of one kilogram — exactly 9.80665 newtons. It is classified as a non-SI unit, deprecated but still encountered.
Is the femtonewton to kilogram-force conversion exact?
Yes. Defined as the force exerted by standard gravity on a mass of one kilogram — exactly 9.80665 newtons. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
What is the difference between kilogram-force vs. newton?
The newton is the modern SI unit of force; kilogram-force is an older, gravity-dependent unit still occasionally seen on legacy equipment. 1 kgf equals exactly 9.80665 N.