Bark Chippings Calculator

Bark chippings or bark mulch for borders and play areas: litres and m³ (or cubic feet and yards) for your area, and the bags or bulk bags to buy.

Bark chippings (bark mulch) are sold in bags of 50 to 100 litres or in bulk bags of around a cubic metre. A layer 5 to 7.5 cm (2 to 3 inches) deep is commonly recommended for suppressing weeds and holding moisture in borders, so a cubic metre covers about 20 m² at 50 mm or 13.3 m² at 75 mm. Enter the size of each area and the depth and this calculator gives the volume in litres and m³ (or cubic feet and yards) and the number of bags of each size. A 4 × 3 m border 50 mm deep needs 0.6 m³, which is 13 bags of 50 litres with 5% extra.

Units
Bag sizes
Area
ft
ft
in
Feet and inches work too: type 12'6 or 12.5.
t/yd³
%
Volume
0.78 yd³

21 ft³ · 0.595 m³

Weight
0.19 tons

389 lb · 0.18 tonnes

Bags
11

2 ft³ bag

Bags needed by size
2 ft³ bag11
3 ft³ bag7
50 L bag12
60 L bag10
70 L bag9
100 L bag6
1 m³ bulk bag1
How it was worked out
  1. Area: 12 ft × 10 ft = 120 ft²; × 2 in (0.167 ft) deep = 20 ft³
  2. 20 ft³ ÷ 27 = 0.74 yd³
  3. Plus 5% extra = 0.78 yd³
  4. 0.78 yd³ × 0.25 tons per yd³ = 0.19 tons (389 lb)
  5. 21 ft³ ÷ 2 ft³ per bag = 10.5, rounded up to 11 bags
Typical weights of common materials
Materialt/m³tons/yd³lb/ft³
Concrete2.402.02150
Gravel1.601.35100
Pea gravel1.601.35100
Crushed stone / crushed rock1.601.35100
River rock1.501.2694
Landscape rock / pebbles1.501.2694
Crushed limestone1.601.35100
Decomposed granite1.501.2694
Crusher run1.601.35100
Road base1.701.43106
Crusher dust1.501.2694
Aggregate (20 mm)1.601.35100
All-in ballast1.651.39103
MOT Type 1 sub-base1.801.52112
Sand1.601.35100
Topsoil1.301.1081
Garden soil1.301.1081
Fill dirt1.401.1887
Mulch0.350.2922
Bark chippings0.300.2519
Asphalt (compacted)2.321.96145

Loose, as-delivered figures; asphalt and concrete are as laid. Moisture, stone size and source change the real weight, so use your supplier's figure when you have it. Tons are US short tons (2,000 lb).

Common use cases

  • Bark mulch for borders and shrub beds
  • Woodland-style paths
  • Play areas (with play-grade bark at the depth your equipment needs)
  • Topping up bark that has broken down

How to use

  1. Choose feet and inches or metres and millimetres, and the country whose bag sizes you want.
  2. Enter the length and width of the area, or switch the shape to a circle, triangle or a known area. Use Add another area for L-shapes and separate beds.
  3. Enter the depth of bark. 5 to 7.5 cm (50 to 75 mm) is typical for borders; play areas need much more.
  4. Check the density and the extra allowance. Change the density if your supplier quotes a different figure.
  5. Read the volume, weight and bag count, and add a price per ton, cubic yard, m³ or bag for a cost estimate.

FAQ

How many bags of bark do I need?

Area × depth gives the volume; divide by the bag size. 10 m² at 50 mm is 0.5 m³ (500 litres), so 10 bags of 50 L, 9 bags of 60 L or 8 bags of 70 L, before extra.

How deep should bark chippings be?

About 5 to 7.5 cm for borders. Thinner layers let weeds through; much deeper can keep water from reaching the soil. Play bark under swings and climbing frames needs a deeper layer set by the fall height, so follow the equipment's safety guidance.

Bark or wood chip?

Bark chippings usually look neater and last a little longer; wood chip is often cheaper and fine for paths and informal areas. Both are measured the same way.

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