Kilogram-force to ton-force (Metric)
kgf
tf
Conversion History
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Quick Reference Table (Kilogram-force to ton-force (Metric))
| Kilogram-force (kgf) | ton-force (Metric) (tf) |
|---|---|
| 1 | 0.001 |
| 5 | 0.005 |
| 10 | 0.01 |
| 70 | 0.07 |
| 100 | 0.1 |
| 500 | 0.5 |
| 1,000 | 1 |
About Kilogram-force (kgf)
The kilogram-force (kgf), also called kilopond (kp), is the gravitational force on a 1-kilogram mass under standard gravity, equal to exactly 9.80665 N. It is widely used in mechanical engineering, hydraulics, and everyday language in countries that have not fully adopted SI force units. Lifting capacity of hoists, safe working loads of chains and slings, and tensile strengths of ropes and cables are often quoted in kgf or tonnes-force in European and Asian manufacturing contexts. Spring balances and older force gauges are calibrated in kgf.
A 70 kg person weighs approximately 70 kgf. A small hydraulic jack rated at 2 tonnes supports 2,000 kgf.
About ton-force (Metric) (tf)
The metric ton-force (tf) is the gravitational force on a 1,000-kilogram mass under standard gravity, equal to exactly 9,806.65 N (approximately 9.807 kN). It is used in heavy industry, crane and hoist ratings, press tooling, marine engineering, and geotechnical pile testing. Crane safe working loads, press capacity, and pile load test results are commonly reported in metric tonnes-force. It is distinct from the short ton-force (US) and long ton-force (UK) due to the different definition of a tonne.
A 50-tonne crane lift involves about 50 tf of force. A large hydraulic press for metal forging may exert 500–5,000 tf.
Kilogram-force – Frequently Asked Questions
Why do some countries still use kilogram-force instead of newtons?
Many countries in Europe and Asia adopted kgf in engineering and industry before SI became dominant. Crane ratings, hydraulic press capacities, and elevator load limits were standardized in kgf and remain labelled that way on existing equipment. Rewriting decades of documentation and re-stamping machinery is costly, so kgf persists in practice even where SI is officially mandated.
How do you convert kilogram-force to newtons?
Multiply kilogram-force by 9.80665 to get newtons. So 1 kgf = 9.80665 N, and 100 kgf = 980.665 N. For quick estimates, multiply by 9.81 or roughly 10. This conversion factor is simply the standard acceleration due to gravity in m/s².
What is the difference between kilogram-force and kilopond?
They are the same unit. Kilopond (kp) was the name used in Germany, Scandinavia, and other European countries, while kilogram-force (kgf) is the internationally recognized term. Both equal the gravitational force on 1 kg at standard gravity. ISO 80000-4 deprecates both in favor of the newton, but kgf remains common in Asian and European industrial contexts.
Why is kilogram-force problematic in engineering calculations?
Using kgf conflates mass and force, leading to errors when gravity varies or when applying F = ma. Engineers must insert a gravitational constant (gₙ = 9.80665 m/s²) to convert between mass and force, which SI avoids by using separate units — kilograms for mass and newtons for force. Mistakes in this conversion have caused real-world structural miscalculations.
What are typical kilogram-force values in everyday life?
A 70 kg adult weighs about 70 kgf. A firm handshake exerts roughly 10–15 kgf. A bicycle tire inflated to 6 bar exerts about 4.5 kgf per cm² on the rim. These values feel intuitive because they numerically match familiar masses, which is precisely why kgf remains popular in non-technical contexts despite SI deprecation.
ton-force (Metric) – Frequently Asked Questions
What metric ton-force rating should you look for when buying a hydraulic jack?
Match the jack to 1.5–2× the heaviest load you will lift. A passenger car weighs 1.2–2.0 tonnes, so a 3 tf bottle jack covers most cars with a safety margin. An SUV or light truck (2.5–3.5 tonnes) needs a 5–6 tf jack. Floor jacks for home garages are typically rated at 2–3 tf. Never work under a vehicle supported only by a jack — always use rated jack stands, because a jack can lose hydraulic pressure without warning.
Why do crane ratings use ton-force instead of kilonewtons?
Crane operators and riggers think in terms of the mass being lifted — "a 20-tonne load" is more intuitive than "a 196 kN load." Ton-force keeps the number identical to the mass in tonnes, which reduces cognitive load and rigging errors on job sites. Many crane load charts list both tf and kN, but the tonne figure is what gets communicated over radio.
What is the difference between metric ton-force, short ton-force, and long ton-force?
Metric ton-force is based on 1,000 kg (9,806.65 N), short ton-force on 2,000 lb / 907.2 kg (8,896.4 N), and long ton-force on 2,240 lb / 1,016 kg (9,964.0 N). The metric and long ton-force are within 2% of each other, while the short ton-force is about 9% smaller. Mixing them up in crane or press specifications can cause dangerous overloads.
How many metric ton-force does a typical hydraulic press exert?
Small workshop presses operate at 10–50 tf, automotive stamping presses at 500–2,500 tf, and the largest forging presses exceed 50,000 tf (about 490 MN). Press manufacturers in Europe and Asia commonly rate capacity in metric tonnes-force, while US makers use short tons or kilonewtons depending on the market.
Is metric ton-force the same as tonne-force?
Yes. "Metric ton-force," "tonne-force," and the symbol "tf" all refer to the same unit: the gravitational force on 1,000 kg at standard gravity. The word "metric" is added to distinguish it from the US short ton-force and the UK long ton-force. In SI-aligned countries, "tonne-force" is the more common phrasing.