How to Find Liquid Volume
- 1). Decide which measuring tool you need by determining the amount of liquid you want to measure. Whether it's a graduated cylinder for a small classroom experiment or something larger, make sure you are measuring for volume with a tool that has clear sides and distinct lines that measure volume.
- 2). Find the volume by locating the lowest level of the meniscus. The meniscus is the curving surface of the liquid. This is caused by the fact the water rises up the edges and drops down in the center of the surface. If you're looking at a graduated cylinder full of water from the side, it might look like it contains 20 ml of water. But when you check the lowest point of the meniscus, you might find out that the volume is actually 19.5 ml.
- 3). Use an online liquid volume conversion tool to convert the volume on your measuring tool to the unit of measurement that suits your purpose. If you need to know how many liters something is but have only a tool that measures ounces, you can plug in your number and have it converted to liters. If you don't have access to the Internet you can multiply the number of fluid ounces by .03 to get the approximate number of liters. So if you have 16 ounces, you can convert that to .48 liter.
Source...