How to Estimate the Capacity of Containers

Evaluate the shape and size of the container of unknown size. This includes estimating the magnitude of all the important dimensions of the container. The dimensions that will be important are length, width, depth and diameter of the container. You should be able to estimate small sizes such as hand widths, arm lengths, or paces. You can measure each of these units to determine an estimate for the dimensions of the container. For example, you measure the size of a long rectangular tube by measuring the size of the square opening and the length of the tube. Use your hand width or distance from the edge of your shoulder to the tip of your middle finger to measure the opening. Assume that it measures 1.5 hand widths by 2 arm lengths. The container is 3 paces long. Volume is calculated by the formula length x width x depth for a rectangular container. Translate the sizes you measure to the actual size of the measurement units. Your arm is approximately 30 inches, your pace is approximately 36 inches and your hand width is approximately 3.5 inches. Your actual unit dimensions will vary. Based on these measurements the dimensions, the estimated size of the container is 5.25 inches x 60 inches x 108 inches. Round these numbers to the nearest whole unit and you will have estimated the capacity of the container as 32,400 cubic inches.

Choose a container that will fill the container of unknown volume between 25 percent and 75 percent of its capacity. You can view the fullness of the container with a known quantity of water filling part of the container. Estimate the percentage of the container that the water fills. You can then divide the amount of water in the container by the appropriate factor to come up with an estimate of the total capacity of the container. For example, You measure 1 gallon of water into a bucket and it fills the bucket approximately 60 percent of the volume. Calculate the total volume of the bucket by dividing 1 gallon by 0.6 to find the total capacity: 1 gallon / 0.60 = 1.667 gallons. The total capacity of the bucket is 1 2/3 gallons.

Approximate the size of larger containers by comparing a measurable item with the size of the larger container. Estimate how many of the smaller object will fit inside the container. Then measure the volume of the smaller item and multiply by the number of smaller items that will fit in the larger container. For example, assume you want to estimate the volume of a container truck. Look at the container truck and decide how many Volkswagen Beetles would fit in the container. You estimate the dimensions of the container as being 1.5 wide by 6 long by 2 high. Then measure the length (4 paces), width (2 paces) and height (shoulder high, approximately 60 inches) of a Beetle. Multiply your estimates by the known measurements to yield the container dimensions of 4.5 feet wide x 10 feet high x 18 feet long. Using length x width x height = volume, the volume of the container is 18 * 4.5 * 10 = 810 cubic feet.