Free Soil Calculator – Cubic Yards & Bags

Soil Calculator Guide

The Soil Calculator estimates cubic yards, cubic meters, and bags of topsoil, garden soil, fill dirt, or compost for beds, lawns, raised planters, and grading. Measure each area in length and width and choose a depth that matches the task: 2-3 inches to topdress an existing lawn, 4-6 inches for a new in-ground planting bed, 8-12 inches to fill a raised bed, and whatever the design calls for when bringing a low spot up to grade. For raised beds and round planters, use the inside dimensions, not the outer frame, so you are not paying for the lumber's thickness. Distinguish the materials: screened topsoil for general planting, a lighter garden-soil blend for vegetables, inexpensive fill dirt for bulk grading where nothing will be planted, and compost as an amendment mixed into existing soil rather than used neat. The tool reports both volume and an approximate weight to help you choose bagged versus bulk delivery.

Formula: cubic yards = length(ft) x width(ft) x depth(in) / 324. Worked example: a raised bed 8 ft long x 4 ft wide filled 12 inches deep = 8 x 4 x 12 / 12 / 27 = 384 / 324 = 1.19 cubic yards, essentially 1 cubic yard. In 1 cu ft bags that is 1.19 x 27 = 32 bags, versus a single bulk scoop, so bulk is cheaper past two or three beds. Metric check: 2.44 m x 1.22 m x 0.305 m = 0.91 cubic meters = 1.19 cubic yards. For a 1,000 sq ft lawn topdressed 0.5 inch: 1000 x 0.5 / 12 / 27 = 1.54 cubic yards. Moist screened topsoil weighs roughly 1 to 1.3 tons per cubic yard, so the 1.54-yard lawn order is about 1.7 tons to move by wheelbarrow.

Order 10-15% extra because loose-delivered soil settles and compacts after watering and foot traffic; raised beds in particular drop noticeably in the first season as organic matter breaks down, so slightly overfilling is normal. The most common mistake is filling an entire raised bed with pure compost or peat blends, which slump, hold too much water, and burn seedlings; a sound mix is roughly 60-70% topsoil or mineral soil with 30-40% compost by volume. A second error is spreading topsoil over compacted construction subgrade without loosening it, which creates a drainage interface where roots stall and water perches. Avoid working or hauling soil when it is waterlogged, since that destroys structure and bakes into clods. There is no single building-code thickness for topsoil, but many erosion-control and stormwater specifications call for a minimum 4-6 inches of stabilized topsoil to establish vegetation; check local grading and drainage ordinances before changing site elevations near property lines.