Use a ruler to measure the three dimensions of the object. These dimensions can be called length, width and depth in most cases, but the exact names will differ depending on the shape.
Find the correct volume formula using your math text book or looking online. Check the "tip" section for a few sample volume formulas to use for this step.
Enter your measurements into the formula. For example, if the measurements of your rectangular prism were "five, six and two" you would create the formula "(5)(6)(2)=V."
Solve the equation by following the order of operations. Solve any squaring first, move onto multiplication and finish with adding. Always move from left to right in solving your equation. For example, you would multiple five, six and two to get 60 cubed as your final answer.