Depending on the variables given, such as force, density or weight, there are three formulas that one can use to find mass. If a weight and acceleration are given, then the formula to find mass is that the weight 'W' is equal to the mass 'm' multiplied by 'g' the acceleration of gravity.
In this formula, W = mg, one can find the mass by rearranging this formula into W/g = m, where g is 9.8 m/ squared seconds.
Another formula is that the force 'F' is equal to the mass 'm' multiplied by 'a' the acceleration constant, or F = ma, where a is 9.8 m/ squared seconds. In this case, the mass is found by the equation F/a = m. The third formula is when the density and volume are the variables given. The formula is that density 'd' is equal to the mass 'm' divided by 'v' the volume, or d = m/v.This becomes dv = m to find the mass.