Raised Garden Bed Soil Calculator

How much soil do you need for a raised bed, and how much should you buy? Plan one bed or several, then compare bagged and bulk material quantities.

Your beds

Project type

Measure the usable inside dimensions of the bed, not the outside dimensions of the frame.

For a full fill, enter the desired soil-filled depth, not necessarily the full wall height.

Bed 1

Bed shape

Inside length (ft)

Inside width (ft)

Desired soil-filled depth (in)

Number of identical beds

Enter a positive whole number.

Add a separate row for each different size or shape. Use the quantity field for identical beds.

Planning allowance

Extra soil allowance (%)

Optional planning allowance for settling, measurement differences, spillage or future topping off. Use 0% if you want the exact geometric fill volume. 10% is an editable example, not a universal settling factor.

Bagged soil

Bag volume (cu ft)

Price per bag ($)

Optional. Material cost uses whole bags.

Bulk soil

Bulk purchase increment (cu yd)

Price per cubic yard ($)

Optional. Confirm your supplier’s available order increments and minimum order.

Bulk calculations are material cost only. Delivery fees, minimum-order fees, taxes and dumping/location charges are not included. Bagged costs also exclude fees and taxes.

Split this soil volume into a mix (optional)

Split the planning volume

Your raised bed soil estimate

cu ft soil to plan for

cu yd

Number of beds
Base geometric soil volume: cu ft
Extra allowance: %
Planning volume in US gallons: gal
Planning volume in liters: L

Bed-by-bed volume

Geometric volume before allowance
Bed / dimensions	Quantity	Each (cu ft)	Subtotal (cu ft)

Bagged purchasing

bags to buy

Volume per bag: cu ft
Exact bags required
Purchased bag volume: cu ft
Unused bag capacity after allowance: cu ft

Bulk purchasing

cu yd to order

Bulk ordered volume: cu ft
Bulk unused capacity after allowance: cu ft

Your user-defined soil mix

Your shares of the allowance-adjusted planning volume
Component	Share	Cu ft	Cu yd

Total share: %. This breakdown is not a recommended recipe; component volumes do not guarantee identical final volume after blending.

Shopping summary

Results are rounded for readability. Purchase rounding uses unrounded quantities; unused capacity is capacity above the allowance-adjusted requirement, not a guaranteed leftover amount.

How it works

For rectangles, we multiply inside length × width × soil depth converted from inches to feet × quantity. For circles, we use π × (inside diameter ÷ 2)² × depth in feet × quantity. We sum the bed volumes and apply your allowance once. Bags round up to whole bags; bulk rounds up only if you choose an order increment.

Full fill or top-up?

For a full fill, depth means the desired soil-filled depth. For a top-up, enter only the amount of new soil being added. An 8 × 4 ft bed needing 3 inches added uses 3 inches—not the full wall height. No existing-bed settling is guessed.

If part of the bed is already occupied by existing soil, a false bottom, logs or another material, enter only the depth/volume that will actually be filled with new soil. Nothing is automatically subtracted, and no filler material is recommended.

Understanding the estimate

This is a volume and purchasing estimate. It does not determine ideal soil composition, nutrient or fertilizer needs, soil pH, drainage design, crop-specific soil depth or structural suitability of a bed. Use your selected product’s stated bag volume. Bulk delivery policies and minimum orders vary by supplier. The allowance is optional planning input, not a guaranteed settling correction.