MEASURE ONCE. BUY WITH CONFIDENCE.

Mulch calculator

Freshen up your flower beds. Work out how much mulch to add, then compare bags with bulk delivery.

01

Your spaces

Measurements

After changing units, use this button before editing dimensions. Enter only the dimensions for your selected shape.Convert units

Sample measurements are filled in to get you started. Replace them with yours.

Area 1

Area name

Shape

Length (ft)Width (ft)

Target depth (in)Already there (in)

We calculate only the depth you still need to add.

02

Your buying options

Prices optional

Use prices from your shop or supplier. Leave prices blank for a quantity-only plan.

Extra material (%)An adjustable allowance, not a compaction factor.Currency

Bagged material

Volume per bag (ft³)Price per bag

Bulk delivery

Price per yd³Delivery feeOrder increment (yd³)Ask whether your supplier rounds to ¼, ½, or whole units.

Working out your order…

No account or saved database record. Shared links include your entered measurements and prices.

TRY THE NUMBERS

Example: top up a bed without buying a full new layer

A 12 × 9 ft bed needs a target depth of 3 inches and already has 1 inch of mulch. Enter both depths; the calculator adds only the missing 2 inches.
12 × 9 × (2 ÷ 12) = 18 cubic feet. With a 10% allowance, the order volume is 19.8 cubic feet.
At 2 cubic feet per bag, round 9.9 up to 10 bags. For bulk sold in quarter-yard steps, 19.8 ÷ 27 rounds up to 0.75 cubic yards.

For several beds, add each area to one plan. The calculator combines their volumes before rounding the bag count.

Open this example in the calculator

Opening the example loads these sample values in place of your current entries.

How to measure

Measure length and width across the bed. Measure the existing mulch separately: in this example, A is 12 ft, B is 9 ft, and the side view shows 1 inch already there plus 2 inches to add.Illustration only; not drawn to scale.

THE MATH, MADE SIMPLE

How this mulch calculator works

We add the volume of every area, subtract the depth of material already there, then add your chosen allowance. Bags round up to whole bags. Bulk rounds up to the order increment you choose.

Rectangle: length × width × added depth.
Circle: π × (diameter ÷ 2)² × added depth.

For imperial measurements, cubic feet ÷ 27 gives cubic yards. For metric measurements, centimetres ÷ 100 gives depth in metres; one cubic metre equals 1,000 litres.

Before you order

Use your supplier’s bag volume and minimum order increment. Prices use your selected currency without exchange conversion. Both options should use the same tax basis.

Bag costs exclude any bag delivery fee. Add that separately if needed. Choose comparable materials when comparing prices.

Read the bags vs bulk guide ↗

Adding fresh mulch?

Measure the existing layer first. University of Maryland Extension advises keeping organic mulch at no more than three inches and away from trunks. Depth needs depend on the material and planting. The default three inches is an editable example, not a prescription for every garden.

Read the extension guidance ↗