buildcalc

Potting Soil Calculator

Estimate potting soil for pots and planters. Enter the container size and count to get total cubic feet and the number of potting-mix bags to buy.

You need approximately
1.85 cubic yards
50 ft³ of soil
With 5% waste: 1.94 cubic yards (recommended when ordering)
Cubic feet
50 ft³
Weight
2 tons
1.5 ft³ bags
34 bags

Containers add up fast, so this view sums pot volume across your count. Use a true potting mix, not garden soil, in containers — dense soil compacts and suffocates roots in a pot.

Why order extra? The headline number is the exact material your project needs. When you actually order, add about 5–10% on top — the “with 5% waste” figure in the result is a safe starting point. That margin covers what you lose to compaction, cuts around edges and corners, and ordinary spillage during handling. It is cheaper to have a little left over than to stop mid-job and wait on a second delivery.

Field notes

Raised beds need more soil than people guess because you're filling a volume, not covering an area — a 4×8 bed a foot deep is 32 cubic feet, roughly 21 bags. Order 10% over for settling, and top up after the first heavy watering when the mix compacts. Blend in compost as you fill rather than layering it; roots don't like a hard interface between mixes.

How the potting soil calculator works

The math behind the tool:

cubic feet = length ft × width ft × depth ft
bags = cubic feet ÷ bag size

Material density

MaterialDensityPer cubic yard
Garden soil 80 lb/ft³ 1.08 tons

Sources: Oregon State University Extension (soil and compost volume guidance).

Frequently asked questions

How much soil do I need for a raised bed?

Multiply the bed length × width × depth in feet to get cubic feet. A 4×8 ft bed filled 10 inches deep needs about 26.7 cubic feet, or roughly 18 bags of 1.5 cubic feet.

How many bags of soil are in a cubic yard?

A cubic yard equals 27 cubic feet, so it takes 18 bags of 1.5 cubic-foot soil or about 13.5 bags of 2 cubic-foot soil to fill one cubic yard.

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