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Compost Calculator

Estimate how much compost you need to amend or topdress your beds.

Common sizes
Shape
Units

Area: 100 sq ft

0.7cubic yards

≈ 19 bags1 cu ft each

Bulk is usually sold in ½-yard increments with a ~1-yard delivery minimum — round up when you order.

Show the math
  1. Area100 sq ft
  2. Volume100 sq ft × 2 in ÷ 1216.7 cu ft
  3. Cubic yards16.7 cu ft ÷ 270.6 cu yd
  4. + 10% waste0.6 × 1.100.7 cu ydthe amount to buy in bulk, before rounding to bags
  5. Bags18.3 cu ft ÷ 1 cu ft/bag19 bagsrounded up to whole bags

Est. cost $24–$41typical bulk price · adjust for your supplier

Bags or bulk for this job?

Bulk delivered$160–$2102.0 cu yd (2-yd min) + ~$90 delivery
Bags$95–$17119 × 1 cu ft · haul ~1 pickup load

For this size, bags usually wins.

≈ 6 wheelbarrow loads to spread · delivery fee varies by distance — confirm at checkout.

  • Low-fi estimate. Confirm coverage and bag sizes with your supplier.
  • Includes a 10% overage allowance.
  • Bag count assumes 1 cu ft bags. Bulk delivery is sold by the cubic yard.

Doing more than one bed or material?

Total the whole yard →See it designed
What are you planning?
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How to measure for compost

  1. Measure the length and width of your area in feet.
  2. Multiply them for square feet (or just enter length and width above).
  3. Choose a depth — we default to 2 inches for compost.
  4. Read your total in cubic yards, or the number of bags.

Compost coverage at a glance (2" deep)

Area (sq ft)Cubic yardsBags
1000.719
2001.437
3002.055
5003.492
1,0006.8184

Includes a 10% overage allowance. Estimates are low-fi — confirm with your supplier.

Frequently asked questions

How much compost do I need?

A 1–2 inch layer is typical for topdressing or amending soil. Enter your area and depth above for an exact estimate.

How much compost for a new garden bed?

To amend a new bed, mix in 2–3 inches of compost into the top 6–8 inches of soil. Use the calculator above with your bed size and that depth.

Bags or bulk?

Bagged compost is usually about 1 cubic foot. Bulk compost (by the cubic yard) is cheaper for larger projects.

Other calculators

Compost Calculator — How Much Compost Do I Need? | GoGarden