What this calculator does
Change a force from one unit to another, such as pounds-force to newtons. Force is a push or pull that changes how something moves. In the metric (SI) system it's measured in newtons. One newton speeds up one kilogram by one meter per second, every second.
Engineering and everyday work still use older units too. Spring scales and bathroom scales are marked in kilograms-force or pounds-force. In the United States, loads on buildings are often given in kips. Older physics books use the dyne.
This converter treats every unit as an exact multiple of the newton. So you can move between any pair without rounding errors creeping in. Enter a force and pick the two units. You get the answer, the working through newtons, and a table of the same force in every unit at once.
Where it's used
Why this math matters outside the classroom:
- Weight as force. A 1 kg mass on Earth weighs about 9.81 N, which is 1 kilogram-force.
- Structural loads. Engineers convert a 50 kip beam load to about 222 kN for a metric design check.
- Climbing gear. A carabiner rated at 24 kN corresponds to about 5,395 lbf.
- CGS units. Students turn 1 N into 100,000 dynes when moving between SI and CGS units.
- Fishing line. A 10 lb test line is rated to break at about 44.5 N of pull.
Grade level and standards: Grades 6–7; Common Core State Standards for Mathematics 6.RP.A.3.d. © Copyright 2010. National Governors Association Center for Best Practices and Council of Chief State School Officers. All rights reserved.
How to use it
- Enter the force. Zero and decimals are fine. Enter the size of the force, not its direction.
- Choose the unit you have and the unit you want.
- Read the result, or use the table to see the force in all seven units. The working shows how many newtons each unit is worth.
What the inputs mean
- Force
- The size of the force, in the From unit.
- From
- Pounds-force (lbf) and kilograms-force (kgf) are forces. Each is the weight of one pound or one kilogram under standard gravity. They aren't the same as the masses lb and kg.
- To
- The unit for the answer. A kip is 1,000 pounds-force.
Formula and method
result = value × (from-unit in N) ÷ (to-unit in N) 1 lbf = 0.45359237 kg × 9.80665 m/s² = 4.4482216152605 N 1 kgf = 1 kg × 9.80665 m/s² = 9.80665 N 1 ozf = 1 lbf ÷ 16 ≈ 0.27801385 N; 1 kip = 1,000 lbf ≈ 4,448.2216 N 1 dyn = 1 g·cm/s² = 0.00001 N; 1 kN = 1,000 N
N is the newton, lbf the pound-force, kgf the kilogram-force, ozf the ounce-force and dyn the dyne. m/s² means meters per second, per second, the unit of acceleration (how fast speed changes).
The gravity-based units start from a mass and standard gravity, g₀ = 9.80665 m/s². That's an exact value scientists agreed on. The pound is set at exactly 0.45359237 kg. So the pound-force works out to exactly 4.4482216152605 newtons, and the ounce-force and kip follow from it.
The converter multiplies your value by the from-unit's size in newtons. Then it divides by the to-unit's size. When either unit is the newton, that step is skipped.
Worked example
A winch is rated to pull 100 pounds-force. What is that in newtons?
- 1 lbf = 4.4482216153 N.
- 100 lbf × 4.4482216153 = 444.822161526 N.
Result: 100 lbf is about 444.82 N.
Understanding the result
As rough guides, 1 lbf is about 4.45 N, 1 kgf is about 9.81 N, and 1 kgf is about 2.2 lbf. A newton is roughly the weight of a small apple.
Sometimes a figure is given in kilograms or pounds but describes a push, pull or load. Then it almost always means kilograms-force or pounds-force.
Assumptions and limitations
- Gravity-based units use standard gravity, exactly 9.80665 m/s².
- The pound is the international avoirdupois pound (the everyday US pound), 0.45359237 kg.
- It converts sizes only. Direction and sign (plus or minus) aren't handled.
- A real object's weight varies slightly from place to place, because local gravity isn't exactly 9.80665 m/s².
- Rarely used units such as the poundal and the sthène aren't included.
Frequently asked questions
Is a pound the same as a pound-force?
Not strictly. A pound (lb) is a mass. A pound-force (lbf) is the pull of standard gravity on that mass. In everyday US speech, "pound" is used for both. That's why a 100 lb load on a beam means 100 lbf.
How many newtons is 1 kg?
A kilogram is a mass, so it has no fixed newton value. Its weight under standard gravity is 1 kgf, which is 9.80665 N. On the Moon the same kilogram would weigh about 1.6 N.
What is a kip used for?
A kip, short for kilopound, is 1,000 pounds-force. US structural engineers use it for loads on beams, columns and foundations. Stress is often given in kips per square inch (ksi).
Where would I see dynes?
The dyne belongs to the older centimeter-gram-second system. It still turns up in physics books and in surface tension (the pull that holds a liquid's surface together), often given in dynes per centimeter. One newton is 100,000 dynes.
How this calculator is checked
Method: SI definition of the newton; international pound (0.45359237 kg) and standard gravity (9.80665 m/s²) for the gravitational units; CGS definition of the dyne. The calculation is covered by automated tests with known reference values and edge cases. Last updated 2026-10-18. Found a problem? Tell us.
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