The SI (International System of Units) unit for force is the newton (N). One newton is defined as the force required to accelerate a one-kilogram mass by one meter per second squared:
1 N = 1 kg * 1 m/s²
In other words, a force of one newton will accelerate a one-kilogram mass by one meter per second squared when applied in the same direction as the force. The newton is the standard unit of force in the metric system.