10-mL graduated cylinder
A graduated cylinder.
If it's a solid multiply the length times the width times the height. If it's a liquid use a graduated cylinder If it's an irregular solid drop it into a beaker, flask, graduated cylinder, or any other water-measuring tool and record how much the water goes up from the original height to the height when the irregular solid was dropped in, and subtract.
To find the volume of a solid you can't simply calculate, get a large tub of water in which you can completely immerse the solid. Fill the tub with water to the edge, then submerge the solid. Any water that spills over has been replaced by the solid and signifies the amount of space the solid is now taking up. Weigh the water or put it in 1l bottles. 1kg of water is 1l and a liter is a cubic decimeter. From there you can calculate the volume in any unit you want.
A ruler to find the measures of the edges and a brain to multiply them together.
A container of liquid in which to immerse the shape.
A ruler or tape measure.
A metric ruler would be the best bet. Simply measure the length, the width and the height of the box and multiple all three measurements together to find the volume of the box in the unit that you measured the boxes in, cubed.
To find the volume of an irregular object, you can use methods like water displacement, where you submerge the object in water and measure the volume of water displaced. You can also use 3D scanning technologies to create a digital model of the object and calculate its volume from the model. Another option is to break the object into simpler geometric shapes, calculate the volumes of those shapes, and then sum them up to get the total volume of the irregular object.
I would use a graduated cylinder or beaker filled part-way with distilled water. By measuring the difference in the height of the water column before and after inserting the object, I would be able to calculate the volume of the object.
Ruler
A graduated cylinder
mearing cup