Convert Femtonewtons to Kilogram-Force

Convert Femtonewtons (fN) to Kilogram-Force (kgf) instantly and accurately.

Femtonewtons (fN)
Kilogram-Force (kgf)

Conversion Formula

kgf = fN × 1.019716213e-16

About Femtonewtons

A femtonewton (fN) is 10⁻¹⁵ N - the force scale of single-molecule biology. RNA polymerase exerts a stall force of ~14-25 fN while transiting DNA at 10-50 bp/s. Myosin V motor proteins step 37 nm with ~1-3 fN per head. The viscous drag on a 100 nm nanoparticle moving at 1 µm/s through cytoplasm is ~0.2-0.5 fN. Optical tweezers with back-focal-plane detection resolve sub-femtonewton forces, enabling measurement of single-enzyme output. AFM receptor-ligand unbinding (e.g., biotin-streptavidin) gives adhesion forces of 100-300 fN. 1 fN = 10⁻¹⁵ N.

About Kilogram-Force

The kilogram-force (kgf), also called the kilopond (kp), is the gravitational force on 1 kg under standard gravity - exactly 9.80665 N. It was the primary force unit in continental European engineering before SI. ISO 1000 (1973) and EU Directive 80/181/EEC deprecated it in favour of the newton. Spring and bathroom scales reading in 'kg' technically measure kgf. Older DIN and JIS materials standards give tensile strength in kgf/mm² (× 9.80665 = MPa). Hydraulic cylinder ratings in legacy European machinery use kgf or tonne-force. 1 kgf = 9.80665 N = 2.20462 lbf.

Quick Reference Table

Femtonewtons (fN)Kilogram-Force (kgf)
1 fN1.02 × 10-16 kgf
2 fN2.039 × 10-16 kgf
5 fN5.099 × 10-16 kgf
10 fN1.02 × 10-15 kgf
25 fN2.549 × 10-15 kgf
50 fN5.099 × 10-15 kgf
100 fN1.02 × 10-14 kgf

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