Raised Bed Soil Volume Calculator

Measure the clear inside length, width, diameter, and finished soil depth. Outside dimensions include board, block, or metal-wall thickness and can overstate the space available for soil.

Use one bed when every bed has different dimensions. Use the identical-bed count only when the footprint and depth truly match.

A rectangular footprint is length multiplied by width. A circular footprint uses the inside diameter and the area formula π(D ÷ 2)².

The L-shape is no longer estimated as an arbitrary percentage of a rectangle. Enter the complete outer rectangle and the missing rectangular corner; the calculator subtracts the cutout area before applying depth.

Full geometric capacity is footprint area multiplied by finished depth and number of identical beds. Initial fill percentage then reduces that capacity when you intentionally leave headroom below the rim.

Settling allowance is added after fill. For example, 90% fill with 10% settling is geometric volume × 0.90 × 1.10, not geometric volume × 1.00. The two settings describe different planning choices.

The calculator converts the adjusted volume into litres, cubic feet, and cubic yards. Enter the volume printed on the bag you plan to purchase; the exact bag requirement is rounded upward because retail bags are normally purchased as whole units.

The result also shows the total bagged volume purchased and the amount above the calculated estimate caused by rounding. Bulk suppliers may sell in minimum quantities or fixed increments, so their quote should control the final order.

Topsoil, compost, and other or aeration percentages divide the adjusted order volume into component quantities. The percentages must total 100% so the worksheet neither creates nor loses volume.

Raised-bed recommendations differ with native soil, product quality, crops, climate, drainage, and nutrient history. University of Minnesota Extension describes a broad topsoil-and-plant-based-compost range, while Oregon State Extension cautions against filling beds with compost alone and gives more conservative compost guidance in some contexts. Local extension advice and soil testing should take priority over a generic mix.

Volume does not determine weight by itself. Two products occupying the same litres can weigh very different amounts because of mineral content, organic matter, moisture, particle size, and compaction.

Enter a density only when the supplier provides a suitable kilograms-per-litre value for the product and condition being ordered. The weight estimate is useful for delivery planning but is not a structural load certification.

The tool does not determine whether the soil is safe, uncontaminated, fertile, correctly drained, or suitable for a crop. USDA NRCS treats soil health as a combination of physical, chemical, and biological properties, including structure, infiltration, nutrient cycling, and organic matter—none of which can be inferred from volume alone.

For food gardens, use reputable material, investigate contamination concerns, and follow local extension or testing guidance. Recheck dimensions and supplier units before spending money because real beds and delivered materials rarely match an ideal geometric model perfectly.