Estimate how much soil or potting mix you need for planter boxes, window boxes, rectangular planters, balcony planters, patio boxes, and raised planter boxes. Calculate cubic feet, quarts, gallons, liters, bags needed, and estimated planter soil cost.
Rectangular mode:
The calculator multiplies length, width, and fill depth to estimate soil volume for a rectangular planter box.
Square mode:
The calculator uses the length value as both length and width for square planter boxes.
Tapered mode:
The calculator averages the top and bottom planter box areas, then multiplies by fill depth.
Known volume mode:
The calculator converts a known planter box size from quarts, gallons, liters, or cubic feet into the amount of soil needed.
A planter box soil calculator helps estimate how much potting mix or container soil to buy before filling planter boxes, window boxes, raised planters, and patio containers.
It can help convert between cubic feet, quarts, gallons, and liters, estimate bag count, compare bag sizes, and reduce the chance of buying too little or too much soil.
Your result shows estimated planter box soil needed in cubic feet, quarts, gallons, and liters. It also shows the number of bags needed, estimated cost, volume per planter, drainage space reduction, root ball space, extra top-off material, and settling allowance.
Multiply the planter box length by width by fill depth. If your measurements are in inches, divide cubic inches by 1,728 to convert to cubic feet.
Use inside dimensions. Outside dimensions include the thickness of the planter box walls and can overestimate the amount of soil needed.
One cubic foot is about 29.92 quarts. This is useful when comparing potting soil bags and planter box volume.
Yes. Adding 5% to 15% extra can help account for settling, spills, and topping off the planter box after watering.
No. This is an estimate. Actual soil needs can vary based on planter shape, tapered sides, drainage material, root ball size, soil settling, and how full the planter box is filled.