How do you convert Kilogram-force to Kilonewton?

Multiply the value in Kilogram-force by the conversion factor 0.00980665 to obtain the result in Kilonewton.

Convert Kilogram-force to Kilonewton (kgf to kN)

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

Convert From (Kilogram-force):

kgf

Result To (Kilonewton):

Copied to clipboard!

In structural, civil, and process engineering, force conversions between legacy gravitational metric units and coherent International System of Units (SI) values are critical for equipment integrity and safety verifications. The kilogram-force (symbol: $\text{kgf}$), sometimes historically termed the kilopond ($\text{kp}$), represents the magnitude of the force exerted by standard Earth gravity on a mass of one international avoirdupois kilogram. By international agreement (CGPM), standard acceleration due to gravity is defined precisely as $g_0 = 9.80665\text{ m/s}^2$. Consequently, one kilogram-force corresponds exactly to $9.80665\text{ N}$.

Conversely, the kilonewton (symbol: $\text{kN}$) is a decimal multiple of the SI base unit of force, the newton ($\text{N}$), where $1\text{ kN} = 10^3\text{ N} = 1{,}000\text{ kg}\cdot\text{m/s}^2$. To convert force expressed in kilogram-force to kilonewtons, apply the exact conversion factor derived from standard gravity:

$1\text{ kgf} = 9.80665\text{ N} = 0.00980665\text{ kN} = 9.80665 \times 10^{-3}\text{ kN}$

Engineering Applications & Technical Considerations

Accurate translation from $\text{kgf}$ to $\text{kN}$ is routinely required across several engineering disciplines:

Piping Stress & Structural Support Sizing: Legacy piping isometric drawings, spring hanger schedules, and pump nozzle allowable load charts originating from East Asian (JIS) or continental European standards frequently tabulate loads in $\text{kgf}$ or metric ton-force ($\text{tf}$). Finite Element Analysis (FEA) software packages (such as CAESAR II, ANSYS, and STAAD.Pro) generally require SI inputs in $\text{N}$ or $\text{kN}$. Misapplying conversion factors directly compromises structural support safety margins.
Hydraulic and Pneumatic Machinery: Material testing apparatus (e.g., tensile and compressive load cells) and hydraulic press ratings manufactured before modern SI mandates are calibrated in $\text{kgf}$. Specifying modern hydraulic actuators or structural anchor bolts requires conversion to $\text{kN}$ to align with modern Eurocode or AISC structural design limits.
Pressure to Force Transformations: Pressure expressed in technical atmospheres ($1\text{ at} = 1\text{ kgf/cm}^2 = 98.0665\text{ kPa}$) generates thrust forces on valve stems, vessel flanges, and pipeline blind flanges. Converting these thrust forces into $\text{kN}$ ensures correct sizing of linear actuators and anchor blocks.

Critical Engineering Pitfalls:

Mass vs. Force Conflation: Engineers must never confuse mass ($\text{kg}$) with force ($\text{kgf}$). While an object with a mass of $1\text{ kg}$ exerts approximately $0.00981\text{ kN}$ at sea level, load calculations in non-standard gravity or dynamic acceleration environments must evaluate inertial forces using Newton's second law ($F = m \cdot a$), rather than assuming $1\text{ kg} = 1\text{ kgf}$.
Premature Rounding: Approximating $1\text{ kgf} \approx 0.01\text{ kN}$ introduces a systemic $+1.97\%$ overestimation. In high-load scenarios—such as offshore mooring tension or foundation pile capacity exceeding $10^5\text{ kgf}$—this error compounds to hundreds of kilonewtons, leading to either costly over-engineering or non-conservative structural assessments.

Kilogram-force to Kilonewton Conversion Reference Table

Kilogram-force (kgf)	Kilonewton (kN)
0.1	9.8067e-04
0.5	0.0049
1.0	0.0098
2.0	0.0196
5.0	0.049
10.0	0.0981
20.0	0.1961
50.0	0.4903
100.0	0.9807
500.0	4.9033
1000.0	9.8066

To convert a dynamic design load of $10\text{ kgf}$ to kilonewtons ($\text{kN}$), apply the exact standard conversion factor $0.00980665\text{ kN/kgf}$:

$$ F_{\text{kN}} = F_{\text{kgf}} \times 0.00980665 \frac{\text{kN}}{\text{kgf}} $$$$ F_{\text{kN}} = 10\text{ kgf} \times 0.00980665\text{ kN/kgf} = 0.0980665\text{ kN} $$

Thus, a force of $10\text{ kgf}$ is equivalent to exactly $0.0980665\text{ kN}$ (or $98.0665\text{ N}$).

The kilogram-force is a gravitational metric unit dependent on the arbitrary baseline of standard gravity ($g_0 = 9.80665\text{ m/s}^2$). It creates ambiguity between mass and force. The kilonewton ($\text{kN}$) is a coherent SI unit derived strictly from base kinematic units ($1\text{ kN} = 1{,}000\text{ kg}\cdot\text{m/s}^2$), which ensures consistency across dynamic, thermodynamic, and static structural calculations without requiring local gravity conversion factors.

To calculate flange thrust force in $\text{kN}$ from pressure in $\text{kgf/cm}^2$: First, convert the pressure to $\text{kN/m}^2$ ($\text{kPa}$) by multiplying by $98.0665$. Then, multiply by the internal cross-sectional area $A$ in square meters ($\text{m}^2$). Alternatively, use the direct formula: $F_{\text{kN}} = P_{\text{kgf/cm}^2} \times A_{\text{cm}^2} \times 0.00980665$.

"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)