In general, there are mainly 2 types of overhead garage door springs:
Extension springs, which extend when the door is lifted and counterbalance the door’s weight. When using extension springs, both springs need to match in order to perfectly balance the door movement.
Torsion springs, which twist inside and create a torque force to lift the weight of the door. When installing new torsion springs, their size needs to be calculated to fit the door’s weight.