- Newton (N): The SI unit of force, named after Sir Isaac Newton. Defined as the force that gives a mass of 1 kilogram an acceleration of 1 meter per second squared (1 N = 1 kg⋅m/s²).

- Pound-force (lbf): Customary unit of force used in the English system. Defined as the force exerted by the weight of 1 pound-mass (0.45359237 kg) in a gravitational field of 9.80665 m/s² (1 lbf = 0.45359237 kg⋅9.80665 m/s²).

- Kilogram-force (kgf): Unit of force based on the kilogram-mass, not widely used. Defined as the force exerted by a mass of 1 kilogram in a gravitational field of 9.80665 m/s² (1 kgf = 1 kg⋅9.80665 m/s²).

- Dyne (dyn): CGS unit of force, rarely used. Defined as the force that gives a mass of 1 gram an acceleration of 1 centimeter per second squared (1 dyn = 1 g⋅cm/s²).