How do you convert Newton to Kilogram-force?

Multiply the value in Newton by the conversion factor 0.10197162129779283 to obtain the result in Kilogram-force.

Convert Newton to Kilogram-force (N to kgf)

Reference ID: EC-FORC-NKG | EngConverter Calculation Guide

Convert From (Newton):

Result To (Kilogram-force):

kgf

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The Newton (N) is the coherent derived unit of force within the International System of Units (SI). Defined by standard principles established by the Conférence Générale des Poids et Mesures (CGPM), one Newton represents the force required to impart an acceleration of one meter per second squared ($1 \text{ m/s}^2$) to a mass of one kilogram ($1 \text{ kg}$). Expressed in fundamental SI base units, $1 \text{ N} = 1 \text{ kg}\cdot\text{m/s}^2$.

Conversely, the kilogram-force (kgf)—also known as the kilopond (kp)—is a non-SI gravimetric unit of force historically used across European and Asian engineering disciplines. It is defined as the magnitude of force exerted by standard Earth gravity ($g_n = 9.80665 \text{ m/s}^2$) on a mass of one kilogram. Consequently, $1 \text{ kgf} \equiv 9.80665 \text{ N}$. To convert Newtons to kilogram-force, the reciprocal mathematical relation is applied:

$1 \text{ N} = \frac{1}{9.80665} \text{ kgf} \approx 0.10197162129779283 \text{ kgf}$

Engineering Applications & Technical Considerations

In process engineering, piping design, and equipment specification, converting force values between SI units (N) and gravimetric customary units (kgf) is frequently required when interfacing modern computational tools with legacy documentation or international vendor data.

Piping Stress Analysis & Support Load Sizing: Finite element analysis (FEA) and piping stress software (e.g., CAESAR II) output support loads, nozzle reactions, and thermal expansion thrusts in Newtons or kiloNewtons (kN). Conversely, legacy site isometric drawings, vendor catalog load tables, and legacy spring hanger specifications often report forces in kgf or metric tons-force (tf). Accurately converting $1 \text{ kN} \approx 101.9716 \text{ kgf}$ ensures structural supports and anchor bolts are properly specified.
Control Valve Actuator Sizing: Linear actuator thrust requirements derived from differential process pressures are typically evaluated in Newtons. Legacy pneumatic actuator specifications frequently list thrust capabilities in kgf. Inaccurate unit conversions can result in inadequate stem force, leading to valve seat leakage or packing binding.
Material Testing & Mechanical Tolerances: Tensile strength, gasket sealing stress, and elastomer tear resistance are often measured in N or $\text{N/mm}^2$ (MPa), whereas legacy workshop instrumentation and testing frames may display values in kgf.

Critical Engineering Pitfalls:

Standard vs. Local Gravitational Fields: The conversion factor relies on standard acceleration of gravity ($g_n = 9.80665 \text{ m/s}^2$). Local gravitational acceleration varies by geography, ranging from roughly $9.780 \text{ m/s}^2$ at the equator to $9.832 \text{ m/s}^2$ at the poles. Calibrating force transducers or load cells using physical deadweights without correcting for local gravity will introduce systematic measurement errors.
Confusion Between Mass ($\text{kg}_m$) and Force ($\text{kg}_f$): Omitting the subscript "f" and writing "kg" for force leads to dimensional errors in dynamic equations ($F = m \cdot a$), where force must remain in Newtons for SI consistency.
Pressure Unit Conversions: Legacy process diagrams frequently express pressure in $\text{kgf/cm}^2$. When converting system pressures to Pascals ($\text{N/m}^2$), engineers must scale both force and area components ($1 \text{ kgf/cm}^2 = 98,066.5 \text{ Pa}$) while ensuring clear accounting of gauge versus absolute pressure references.
Significant Figures & Truncation: Truncating the conversion factor to $0.1$ introduces a $1.97\%$ error. For high-pressure flange torque calculations or pressure relief valve reaction force determinations, maintain at least six significant figures ($0.101972$) to prevent compound engineering errors.

Newton to Kilogram-force Conversion Reference Table

Newton (N)	Kilogram-force (kgf)
0.1	0.0102
0.5	0.051
1.0	0.102
2.0	0.2039
5.0	0.5099
10.0	1.0197
20.0	2.0394
50.0	5.0986
100.0	10.1972
500.0	50.9858
1000.0	101.9716

To convert a force of 10 Newtons (N) to kilogram-force (kgf), multiply the force value by the standard conversion factor $0.1019716213$:

\$$ F_{\text{kgf}} = F_{\text{N}} \times 0.1019716213 \text{ kgf/N} \$$

Applying the calculation for 10 N:

\$$ F_{\text{kgf}} = 10 \text{ N} \times 0.10197162129779283 \frac{\text{kgf}}{\text{N}} = 1.019716213 \text{ kgf} \$$

Thus, 10 N is equivalent to 1.01972 kgf (rounded to five decimal places).

The CGPM deprecated the kilogram-force because it depends on standard gravitational acceleration ($g_n$), creating ambiguity between mass (kilograms) and force (kilogram-force). Modern SI standards mandate the Newton (N) because it is defined independently of gravitational variation. However, kgf remains common in legacy Asian and European technical drawings, spring hanger sizing tables, and legacy valve actuator ratings.

The standard conversion factor ($1 \text{ N} = 0.1019716 \text{ kgf}$) assumes standard nominal gravity ($9.80665 \text{ m/s}^2$). In field calibrations, actual local gravity ($g_{\text{local}}$) can range from $9.78 \text{ m/s}^2$ to $9.83 \text{ m/s}^2$. When calibrating a load cell measuring in Newtons using physical test weights (kg), the actual applied force is $F = m \cdot g_{\text{local}}$. Neglecting local gravity variations can introduce calibration errors up to $\pm 0.3\%$.

"On fait la science avec des faits, comme on fait une maison avec des pierres ; mais une accumulation de faits n'est pas plus une science qu'un tas de pierres n'est une maison."
"Science is built up of facts, as a house is built of stones; but an accumulation of facts is no more a science than a heap of stones is a house."
— Henri Poincaré (French Mathematician, Theoretical Physicist & Mining Engineer)