Mulch Bag Calculator: Never Guess Your Bag Count Again
Avoid making multiple trips to B&Q or Wickes. Enter your garden measurements below to get an exact count of 50L, 60L, 70L, or bulk builder bags.
MULCH ESTIMATOR
FREEHow much do you need?
YOUR ESTIMATE
0.825 m³825 litres including 10% extra
Area15 m²
50L bags17
Est. cost£93.5
We round bags up so you are not caught short. Base quantity before allowance: 750 litres.
Common UK Mulch Bag Sizes & Their Coverage
Unlike in the US where mulch bags are sold by cubic feet (usually 2 cu ft), UK retailers package mulch in litres. Here is what each standard size covers at a recommended 5 cm (2 inch) depth:
| Bag Size | Volume in m³ | Coverage at 5cm (2") | Coverage at 7.5cm (3") | Typical UK Price |
|---|---|---|---|---|
| 40 Litre Bag | 0.04 m³ | 0.8 m² (8.6 sq ft) | 0.53 m² (5.7 sq ft) | £3.50 – £5.00 |
| 50 Litre Bag (Most Popular) | 0.05 m³ | 1.0 m² (10.7 sq ft) | 0.66 m² (7.1 sq ft) | £4.50 – £6.50 |
| 60 Litre Bag | 0.06 m³ | 1.2 m² (12.9 sq ft) | 0.80 m² (8.6 sq ft) | £5.50 – £7.50 |
| 70 Litre Bag | 0.07 m³ | 1.4 m² (15.0 sq ft) | 0.93 m² (10.0 sq ft) | £6.50 – £9.00 |
| 850 Litre Bulk Bag | 0.85 m³ | 17.0 m² (183 sq ft) | 11.3 m² (122 sq ft) | £75.00 – £105.00 |
| 1,000 Litre (1 m³) Bulk Bag | 1.00 m³ | 20.0 m² (215 sq ft) | 13.3 m² (143 sq ft) | £85.00 – £120.00 |
Small Bags vs Bulk Dumpy Bags: Which Saves More Money?
When planning a UK garden project, deciding between 50L bags and an 850L bulk dumpy bag comes down to two factors: total volume and delivery access.
- Cost per Litre Comparison: Buying twenty 50L bags (£5.50 each) equals £110 for 1,000 litres. A 1,000L bulk bag from a trade builders merchant often costs £85 delivered—a saving of £25 on material alone.
- Physical Handling & Access: If your garden is accessed through a terraced house or narrow side passageway, bulk bags cannot be placed in the back garden. In this situation, smaller 50L or 70L bags that you can carry in a wheelbarrow are far more practical.
- Storage: Plastic-wrapped bags can be stored outdoors for several months without degrading, whereas open bulk bags need immediate spreading or tarp coverage during rainy British weather.
The Bag Count Math Formula
To work out your exact bag count manually:
UK BAG FORMULA
Bags = (Area in m² × Depth in cm × 10) ÷ Bag Litre Capacity
Always round up to the next full bag and add 10% for natural compaction.