Measure your beds
Enter the length and width of a rectangular bed, or the diameter of a round one. Break an irregular garden into a few simple shapes.
Mulch Calculator
Calculate mulch volume, bags and cost for your garden beds.
Garden measurements
Garden beds
Depth and bag size
Quick pick
Topping up? Enter only the extra depth you need.
A little space goes a long way. Keep mulch away from stems and tree trunks. For many wood and bark mulches, a total layer of 2–3 inches is enough. Read the depth guide
FROM MEASUREMENTS TO MULCH
How to calculate mulch
A simple way to work out how much mulch you need.
Choose your depth
Set the depth you want to add. If mulch is already in place, measure it first and add only enough to reach your planned total.
Get your shopping list
See the total volume for a bulk order or the number of whole bags. Add your supplier's prices to compare the two options.
GOOD ROOTS START HERE
How deep should
your mulch be?
For many wood and bark mulches, a total layer of 2–3 inches (about 5–8 cm) is a useful starting point. Material, drainage and existing mulch all matter.
Keep the trunk flare visible and leave about 3 inches of space around tree trunks. Mulch should never be piled against bark.
Guidance from Clemson Extension ↗ and University of Maryland Extension ↗.
A layer, not a mountain.
Coarse pine bark may suit a deeper layer; finer materials may need less. Check the guidance for your mulch and plants.
A FEW HANDY ANSWERS
Mulch calculator FAQs
How do I calculate how much mulch I need?
Multiply the bed's area by the mulch depth. With feet and inches, use: cubic yards = length (ft) × width (ft) × depth (in) ÷ 324. In metric, cubic meters = area (m²) × depth (cm) ÷ 100. For a circle, area is π × radius². This calculator adds up all your beds before working out the bags.
How many bags of mulch are in a cubic yard?
One cubic yard is 27 cubic feet. That means 27 one-cubic-foot bags, 18 bags of 1.5 cubic feet, or 9 three-cubic-foot bags. For two-cubic-foot bags, you'll need 14 whole bags to cover one cubic yard, with a little left over.
How much does a bag of mulch cover?
A 2-cubic-foot bag covers 12 square feet at 2 inches deep, or 8 square feet at 3 inches deep. A 50-liter bag covers 1 square meter at 5 cm deep. Check the actual volume printed on your bag.
Should I buy bags or order bulk mulch?
Compare the bulk price for your volume with the price of the whole bags you need. Bulk delivery can be convenient for larger projects; bags are easy to move into separate beds. Include delivery fees, minimum orders and taxes when making your final comparison.
Do I need an extra allowance?
An optional 5–10% allowance can give you flexibility for uneven ground or imperfect measurements. It increases your shopping quantity, not the recommended mulch depth. Select “None” if you want the calculated volume alone.
Can I use this for more than one garden bed?
Yes. Add rectangular and circular beds and we'll total their areas. All beds use the same depth. For beds needing different depths, calculate them separately. For a tree ring, subtract the unmulched center area from your measurements rather than counting the whole circle.
Small calculations. Happy gardens.
Free to use. No accounts, no uploads. Your measurements stay in this browser.