The math
We find the space you want to fill. Length times width times depth gives cubic feet. 27 cubic feet make 1 cubic yard.
Each calculator shows its math under the answer, step by step. You can check it by hand.
Our tests check the math each time we change a page.
Weights
A yard of stone or soil can weigh more or less. It depends on the rock, how wet it is and how packed it is.
So we use weights from people who measure them. That means makers of heavy machines, the US EPA, and state university extension offices.
When sources do not agree, we show a low and a high weight.
Prices
Prices come from what landscape yards, garden centers and dealers post on their own sites or price sheets. We look for sellers all over the US.
We write down each price with the seller's own words and the date. Then we drop the lowest tenth and the highest tenth. The range you see is what is left.
Prices are before delivery and tax. We do not name the sellers. We do not use cost guides or other calculator sites.
Your price will be different. Every calculator lets you type your own.
Frost dates and zones
Frost dates come from the NOAA climate normals for 1991 to 2020. We use a weather station near your ZIP code.
Your plant hardiness zone comes from the 2023 USDA map, made by the PRISM group at Oregon State University.
When to plant each vegetable comes from Colorado State University Extension.
Sources and dates
Each page lists its sources at the bottom, with a link and a date.
Each page also shows when we last checked it. When a source changes, we change the page.