Landscape materials are sold in a confusing mix of units: cubic yards (or cubic metres) for mulch and soil, metric tonnes for stone and sand, and bags of every size at the home centre. Everything starts from the same volume calculation, then converts to however the supplier sells it.
Volume first
volume = area × depth. Convert depth to feet before multiplying (3" = 0.25 ft), then divide cubic feet by 27 to get cubic yards. For beds with curved edges, measure the longest length and the average width, or split the bed into shapes.
Weight from volume
| Material | Approx. density |
|---|---|
| Crushed stone / gravel | 1.5–1.7 t/m³ (1.2–1.3 t per cu yd) |
| Pea gravel | about 1.55 t/m³ (1.2 t per cu yd) |
| Sand (dry) | 1.5–1.6 t/m³ (1.15–1.2 t per cu yd) |
| Topsoil | 1.2–1.4 t/m³ (0.9–1.1 t per cu yd) |
| Road base / crusher run | 2.0–2.2 t/m³ (1.5–1.7 t per cu yd) |
| Mulch | about 0.35–0.45 t/m³ (0.3 t per cu yd) |
Wet material is heavier, often by 10–20%, which matters when you're buying by weight or checking a trailer's payload.
Recommended depths
| Use | Depth |
|---|---|
| Mulch or bark in beds | 2–3" |
| Decorative gravel on paths | 2–3" over a compacted base |
| Gravel driveway surface | 3–4" over 4–6" of base |
| Topsoil for new lawn | 4–6" |
| Play sand | 12" or more |
What a yard covers
One cubic yard covers 324 sq ft at 1", 162 sq ft at 2", 108 sq ft at 3" and 81 sq ft at 4".
Bags vs bulk
A cubic yard is 13.5 bags of 2 cu ft mulch, 9 bags of 3 cu ft, or about 54 bags of 0.5 cu ft gravel. Bulk is almost always cheaper above a yard or two, as long as there's somewhere to tip it.
Think about delivery too. Bulk loads are tipped on a driveway or lifted off by a crane, then barrowed to where they're needed. Bags can go straight to the backyard, but they're slower and leave a lot of plastic.
Compaction and settling
Base materials compact by 15–25%, and loose soil settles 15–20%. Add these allowances to the volume, or you'll come up short. Mulch breaks down over a season and needs topping up, typically an inch a year.
Under the gravel
A weed membrane under decorative gravel saves hours of weeding. On paths and drives, edging keeps stone out of lawns and beds and is worth including in every quote.
Use the gravel, mulch, topsoil and sand calculators. Each shows volume, weight, bags and bulk quantities together.
A worked example
A 40 × 10 ft gravel path at 3": 400 sq ft × 0.25 ft = 100 cu ft = 3.7 cu yd (2.8 m³). At 1.6 tonnes per cubic metre that's 4.5 tonnes. Add 5%: order 4.75 tonnes, plus a 3 × 150 ft roll of landscape fabric.
Ordering tips
- Ask what the supplier's "load" or "bag" actually holds. Sizes vary.
- Check delivery access and where the load will be tipped. A dump truck needs firm ground and clearance.
- Put down a tarp before a bulk load is tipped on a driveway. It saves an hour of clean-up.
- Order a little extra on decorative gravel. Matching it later from a different quarry batch can be hard.
Choosing the right material
- Paths and drives need angular, crushed stone that locks together. Round pea gravel rolls underfoot and migrates, so it's best for borders and drainage.
- Bases under paving and sheds need a well-graded material with fines (crusher run or road base) that compacts hard.
- Drainage needs clean stone with no fines, so water can flow through it.
- Bedding sand for pavers is sharp, coarse sand, not soft building sand, which stays plastic and moves.
- Mulch varies from fine shredded bark, which breaks down fast and feeds the soil, to large nuggets that last longer but blow and float away.
When in doubt, ask the supplier what they recommend for the use. A cheaper material that doesn't suit the job costs more in callbacks.
Common questions
How much does a yard of mulch weigh?
A cubic yard of shredded mulch weighs roughly 600–800 lb dry and more when wet, much lighter than stone. That's why mulch is sold by volume and stone by weight.
Can my pickup carry it?
Check the payload first. Many half-ton pickups carry well under a cubic yard of gravel, which weighs about 1.2 tonnes. The material weight calculator works out how many trips a load needs.
This guide is general information for estimating. It is not engineering, legal or tax advice. Check local codes and your inspector for your project.