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Estimate how much mulch (straw, wood chips, bark or plastic film) you need to cover a given area at a target thickness, and the resulting weight and cost.
Enter the area to cover, desired mulch thickness, mulch type (which sets the bulk density) and unit price. The calculator returns volume in m³ and cubic yards, weight and cost.
You ordered 10 m³ of wood chips for a 100 m² garden and spread them 10 cm thick. The pile disappeared in an hour — 10 m³ at 10 cm covers only 100 m², exactly what you expected, but chips settle to half their loose volume after a month.
✓ Expert Reviewed: This calculator and its content have been reviewed by agricultural experts. Formulas are based on standard extension service recommendations. For site-specific advice, consult your local agronomist.
Enter the area in m², desired mulch thickness in cm, select mulch type (straw, wood chips, bark or plastic) and enter local price per m³. Click Calculate to see volume, weight and cost.
Volume = area × thickness. Bulk densities are typical: straw 150 kg/m³, wood chips 250 kg/m³, bark/shredded 500 kg/m³. Plastic film has no meaningful volume (it is a sheet) and weight is shown only for organic mulches.
Volume (m³) = Area (m²) × Depth (m). Cubic yards = Volume × 1.308. Weight (t) = Volume × Density (kg/m³) ÷ 1000. Cost = Volume × Unit price.
100 m² at 5 cm (0.05 m) wood chips: volume = 100 × 0.05 = 5 m³. Weight = 5 × 250 ÷ 1000 = 1.25 t. At $40/m³, cost = $200.
Common mistakes: ordering by weight instead of volume (mulch is sold by volume), not accounting for settling (organic mulches settle by 30–50% over 6 months), applying too thick (over 15 cm can smother plants), and forgetting to account for pathways or non-planted area.
Most organic mulches are applied 5–10 cm (2–4 inches) deep. Thinner layers do not suppress weeds; thicker than 15 cm can block water and oxygen. For vegetable gardens, 5 cm is typical; for landscape beds, 7–10 cm is standard.
Straw, hay and chopped leaves are cheap, light and easy to incorporate. Wood chips last longer but can tie up nitrogen as they decompose near the soil surface. Plastic film warms soil early but does not improve soil biology. Choose based on crop, climate and budget.
Wood chips: ~400–500 kg/yd³ (600–800 lb). Bark: ~500–700 kg/yd³. Straw: ~150–250 kg/yd³. Bulk density varies with moisture and settling — wet mulch can weigh twice as much as dry.
Yes. A 5 cm organic mulch reduces soil evaporation by 50–70% and keeps soil 5–10 °C cooler in summer. It also suppresses weeds (reduces weed seed germination by ~80%), improving water availability for the crop.
Straw or hay breaks down in 1 season and needs annual reapplication. Wood chips last 2–3 years. Bark nuggets last 3–5 years. Top up as it decomposes; do not pile mulch against plant stems (it causes rot and collar pests).