Mulch Coverage Calculator: Area & Depth Planning for UK Gardens
How much area will your bark or compost cover? Calculate exact square metre (m²) or square foot coverage at any application depth.
MULCH ESTIMATOR
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YOUR ESTIMATE
1.375 m³1,375 litres including 10% extra
Area25 m²
60L bags23
Est. cost£195.5
We round bags up so you are not caught short. Base quantity before allowance: 1,250 litres.
Mulch Coverage Rates by Volume & Bag Size
Coverage depends directly on thickness. Here is how much area different volumes cover in British metric units:
| Volume / Bag | At 2.5cm (1") Depth | At 5.0cm (2") Depth | At 7.5cm (3") Depth | At 10cm (4") Depth |
|---|---|---|---|---|
| 50 Litres (1 bag) | 2.0 m² (21.5 sq ft) | 1.0 m² (10.7 sq ft) | 0.66 m² (7.1 sq ft) | 0.50 m² (5.4 sq ft) |
| 70 Litres (1 bag) | 2.8 m² (30.1 sq ft) | 1.4 m² (15.1 sq ft) | 0.93 m² (10.0 sq ft) | 0.70 m² (7.5 sq ft) |
| 500 Litres (10 bags) | 20.0 m² (215 sq ft) | 10.0 m² (107 sq ft) | 6.6 m² (71 sq ft) | 5.0 m² (54 sq ft) |
| 850 Litres (1 Bulk Bag) | 34.0 m² (366 sq ft) | 17.0 m² (183 sq ft) | 11.3 m² (122 sq ft) | 8.5 m² (91 sq ft) |
| 1,000 Litres (1 m³) | 40.0 m² (430 sq ft) | 20.0 m² (215 sq ft) | 13.3 m² (143 sq ft) | 10.0 m² (107 sq ft) |
Recommended Depth by Garden Purpose
- Ornamental Borders & Shrub Beds (5 cm / 2 inches): Optimal balance between moisture conservation and root breathability. Deeper than 5cm around delicate perennials may cause collar rot.
- Weed Suppression on Heavy Soil (7.5 cm / 3 inches): Blocks sunlight from reaching dormant weed seeds. Ideal for gravel garden borders, heavy clay beds, and newly established tree rings.
- Garden Paths & High-Traffic Areas (10 cm / 4 inches): Gives a springy, durable walking surface that cushions footsteps and prevents muddy patches during British winters.
- Children's Play Areas (15 cm – 30 cm / 6 – 12 inches): Play bark or safety rubber mulch must be laid deeply to satisfy BS EN 1177 impact attenuation standards for swing sets and climbing frames.
3 Practical Tips for Maximum Coverage Efficiency
- Weed and Water Before Mulching: Mulch acts as an insulating blanket. If applied to bone-dry soil, it can delay rainfall from soaking down. Water beds thoroughly and remove perennial weeds before spreading.
- Leave a 5–10cm Breathing Collar: Never pile mulch directly against tree trunks or woody shrub stems ("mulch volcanos"). Keep a clear circle around main stems to avoid fungal infection.
- Account for Slopes: Bark chippings on steep garden banks can wash down during heavy downpours. Use shredded bark or composted wood mulch with interlocking fibres on slopes to prevent migration.