Landscaping
Mulch Calculator
Enter your bed dimensions in metres (or feet — both work) and the depth in centimetres to get the mulch volume in cubic metres and litres, plus a bag count.
Formula tested · Local units · No sign-up
Project inputs
Enter measurements
Use your preferred units. Results update automatically.
Show the calculation methodFormula, conversions, rounding, and assumptions+
Volume = bed area × depth, converted to metres before multiplying — a 7.5 cm layer on a 12 m² bed is 12 × 0.075 = 0.9 m³ (900 litres).
Canadian garden centres sell mulch both in litre bags and in cubic-foot bags (2 cu ft ≈ 56.6 L), plus bulk by the cubic yard or cubic metre — so check your product's stated size and enter it. Bag counts round up to whole bags.
Real-world example
Worked example: 4 m × 3 m bed, 7.5 cm deep
- Area: 4 × 3 = 12 m².
- Convert depth: 7.5 cm = 0.075 m.
- Volume: 12 × 0.075 = 0.9 m³.
- Add 5% wastage: 0.9 × 1.05 = 0.945 m³ = 945 litres.
- Bags: 945 ÷ 50 = 18.9, rounded up to 19 bags of 50 L.
Buy 19 bags of 50 L. Enter your store's price per bag for a cost estimate — add your provincial GST/HST rate on top if the shelf price excludes it.
Before you start
How to measure
- Measure beds in metres or feet — the calculator converts either; just keep each measurement's unit selector correct.
- Choose depth by job: 5 cm (about 2 inches) tops up existing beds, 7–10 cm (3–4 inches) suits new beds and weed control.
- For beds along a curved walkway, approximate with rectangles, add the areas, and use the total-area mode.
Local guidance
Notes for Canada
- Canadian bag sizes mix systems: some products are labelled in litres, others in cubic feet (2 cu ft ≈ 56.6 L) — convert or edit the bag-size field to match your product.
- Bulk mulch from landscape depots may be quoted per cubic yard or per cubic metre; the calculator shows the total in m³ and litres so you can compare either way.
- Sales tax is 5% GST plus provincial tax or a combined HST depending on the province; shelf prices usually exclude it.
Quick reference
Mulch depth quick reference (typical planning values)
| Application | Common depth |
|---|---|
| Annual top-up of existing beds | 3–5 cm (1–2 in) |
| General beds and borders | 5–8 cm (2–3 in) |
| New beds / weed suppression | 8–10 cm (3–4 in) |
| Around trees (clear of trunk) | 5–10 cm (2–4 in) |
Planning values only — over-mulching holds excess moisture against stems.
Good to know
Common mistakes to avoid
- Entering a bag labelled in cubic feet as if it were litres — a 2 cu ft bag is about 56.6 L, not 2 L.
- Mixing feet and metres in the same calculation without setting each field's unit.
- Skipping wastage: mulch settles after the first rain, so 5% extra is a sensible buffer.
- Comparing a per-cubic-yard bulk quote against a per-cubic-metre one without converting (1 yd³ ≈ 0.765 m³).
Need help?
Frequently asked questions
How many litres is a 2 cubic foot bag?
About 56.6 litres (1 cubic foot = 28.32 L). If your bags are labelled in cubic feet, enter 56.6 in the bag-size field for a 2 cu ft bag.
How much mulch for a 15 m² bed at 7.5 cm?
15 × 0.075 = 1.125 m³. With 5% wastage that's 1.181 m³ ≈ 1,181 litres, which is 24 bags of 50 L (1,181 ÷ 50 = 23.6, rounded up).
Is a cubic yard of bulk mulch more than a cubic metre?
No — it's less. A cubic yard is about 0.765 m³, so a per-yard price needs to be about 31% higher than a per-metre price to be equivalent. The calculator's m³ total lets you compare both quotes.
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About this calculator
- Written by:
- BuildMeasure Editorial Team
- Technically reviewed by:
- Pending independent technical reviewer (formula unit-tested; see methodology)
- Last reviewed:
- 2026-07-16
- Formula version:
- 1.0.0
- Region reviewed for:
- Canada
- Spotted an error?
- Report a correction
Methodology
- Volume is computed as bed area × depth. You can enter the area directly or as length × width; either way all inputs are converted to SI units (metres) before any arithmetic to avoid unit drift.
- The wastage allowance is applied to the exact volume to cover settling and uneven spreading.
- Bag counts divide the total volume by the bag size you enter and round UP to whole bags, because you can't buy a fraction of a bag. The default bag size is a clearly-labelled common retail size (2 cubic feet in the US, 50 litres elsewhere) and is fully editable.
- The cost estimate simply multiplies the bag count by the price you enter. No prices are built in.
- The formula is covered by automated unit tests, including hand-calculated worked examples, and is versioned (see formula version on this page).
Sources & standards
- Unit definitions: 1 ft³ = 28.316846592 L and 1 yd³ = 0.764554857984 m³ (exact definitions).
- Bag sizes: 50 L is used as an editable default; Canadian retail also sells cubic-foot bags — check your product.
This tool provides a material estimate for planning purposes only. It is not a quotation. Bag sizes and coverage vary by product, and mulch settles over time — confirm quantities and product sizes with your supplier before buying.