Manure Calculator
Enter your garden bed or lawn area and how deep you want to spread it to get the cubic yards, tons, and bag count of composted manure you’ll need.
Measure straight across the widest point.
Adjust depth below if needed.
Covers spillage and compaction. 5–10% is normal.
Everything is calculated in your browser. Nothing you type is sent anywhere or stored.
Bags or bulk delivery?
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Coverage & weight
Material profile
For the default 20 ft × 10 ft bed at a 2-inch layer, you’ll need about 1.36 cubic yards (0.68 tons) of composted cow manure, including a 10% waste allowance. Round up to 0.75 tons when ordering bulk — about $103.95 delivered, versus $407 in 0.5 cu ft bags.
Manure needed for common project sizes
These estimates use composted cow manure at 1,000 lb per cubic yard with a 10% waste allowance built in.
| Project | Depth | Cubic yards | Tons |
|---|---|---|---|
| Small garden bed top-dress, 100 sq ft | 2 in | 0.68 yd³ | 0.34 tons |
| Medium garden bed, 400 sq ft | 2 in | 2.72 yd³ | 1.36 tons |
| Vegetable bed mix-in, 400 sq ft | 3 in | 4.07 yd³ | 2.04 tons |
| Large garden bed, 1,000 sq ft | 2 in | 6.79 yd³ | 3.4 tons |
| Lawn top-dress, 2,000 sq ft | 1/2 in | 3.4 yd³ | 1.7 tons |
| Row garden, 600 sq ft | 2 in | 4.07 yd³ | 2.04 tons |
Manure types, weight and best use
| Type | Weight per yd³ | Best for | Drainage |
|---|---|---|---|
| Composted cow manure | 1,000 lb | General garden beds | Good |
| Mushroom compost (spent manure) | 950 lb | Vegetable gardens, raised beds | Good |
| Composted chicken manure | 900 lb | High-nitrogen boost, use sparingly | Good |
Figures are for dry material. Wet or freshly delivered material can weigh noticeably more.
How to calculate manure you need
- Measure your bed or plot length × width in feet, or use the circle/border option for irregular beds.
- Set the application depth 1/2in for a thin lawn top-dress, 2in for a garden bed top-dress, 3in if tilling it into a vegetable bed.
- Pick a manure type composted cow manure for general beds, mushroom compost for vegetables, or chicken manure sparingly for a nitrogen boost.
- Add waste 10% covers spillage and settling during spreading and tilling.
- Compare bulk vs. bagged cost bulk delivery wins once a job passes roughly half a ton of material.
Worked example
Using the calculator’s default 20 ft × 10 ft bed top-dressed 2 inches deep with composted cow manure:
- Area20 ft × 10 ft = 200 sq ft
- Depth in feet2 in ÷ 12 = 0.167 ft
- Volume200 sq ft × 0.167 ft = 33.33 cu ft
- Plus 10% waste33.33 × 1.10 = 36.67 cu ft
- Cubic yards36.67 ÷ 27 = 1.36 yd³
- Weight (composted cow manure, 1,000 lb/yd³)1.36 × 1,000 = 1,358 lb = 0.679 tons
- Order amountRound up to 0.75 tons — most yards sell in quarter-ton increments
- Bulk vs. bagged costBulk: 0.679 tons × $50/ton + $70 delivery = $103.95. Bags: 74 × $5.50 = $407.00
Recommended depth by project
| Project | Recommended depth | Notes |
|---|---|---|
| Thin lawn top-dress | 1/2 in | Light nitrogen boost; water in well to avoid burning grass |
| Garden bed top-dress | 2 in | Standard surface application, worked in lightly with a rake |
| Vegetable bed mix-in | 3 in | Tilled into the top 6-8in of soil before planting |
| New bed prep (fresh manure) | 3-4 in | Till in at least 90-120 days before harvest if manure isn't fully composted |
| Raised bed blend | 10-20% by volume | Mixed into existing soil rather than applied as a surface layer |
Bags or bulk delivery?
Bagged composted manure (0.5 cu ft) is convenient for container gardens and small beds, but bulk delivery is far cheaper per ton once a project needs more than about half a ton. Composted manure in bulk is also usually better value than the small bags sold at garden centers.
- Small beds/containersunder 0.5 ton (roughly 30-40 bags) — bags are easiest for a raised bed or two.
- Medium gardens0.5 to 2 tons — compare bulk-plus-delivery against the bag total.
- Large plots/lawnsover 2 tons — bulk delivery is almost always the cheaper, faster option.
Common mistakes
- Using fresh, uncomposted manure on food cropsraw manure can carry pathogens; it needs at least 90-120 days of composting or aging before it touches edible parts of vegetables.
- Over-applying nitrogen-heavy manurechicken manure is much stronger than cow manure — a 2in layer of it can burn plants and over-fertilize; use it sparingly or blend it thin.
- Not tilling it in on new bedssurface-applied manure loses nitrogen to the air; till it into the top several inches for new beds to retain more nutrients.
- Applying too close to plantingfresh or hot manure needs time to mellow — apply at least a few weeks before planting to avoid root burn.
- Ignoring salt buildupmanure applied year after year without soil testing can build up salts and phosphorus; rotate with other amendments and test soil every few years.
- Confusing composted and mushroom compost densitymushroom compost is lighter and often includes lime and other amendments — check the label’s nutrient content, not just weight.
What this calculator assumes
Adjust your result if your project differs from these.
- Depth is the applied layer thickness before it settles or is tilled in.
- Default material is composted cow manure at roughly 1,000 lb per cubic yard; density varies by moisture content and source.
- 10% waste covers spillage and settling during spreading.
- Prices are material only — delivery, spreading, and tilling labor are separate.
- Manure is assumed fully composted/aged; fresh manure needs additional time before planting food crops.
- Bag size is 0.5 cu ft, a common retail size for composted manure.
Common questions
How much manure do I need per square foot?
For a standard 2-inch top-dress, figure about 0.17 cubic feet per sq ft before waste — or use the calculator above with your exact area.
Is composted or fresh manure better for gardens?
Composted manure is safer and more convenient — it won’t burn plants and has no pathogen risk. Fresh manure has more nutrients but must age at least 90-120 days before touching food crops.
How deep should I apply manure to a garden bed?
2 inches as a surface top-dress, or 3 inches if you’re tilling it into a vegetable bed before planting.
Can I use too much manure?
Yes — especially chicken manure, which is high in nitrogen and can burn roots or over-fertilize in a thick layer. Apply it thinner than cow manure or mushroom compost.
How much does a cubic yard of manure cover?
One cubic yard covers about 160 sq ft at 2 inches deep, or roughly 325 sq ft at 1 inch.
Is mushroom compost the same as manure?
Mushroom compost is spent substrate used to grow mushrooms, which typically includes composted horse or poultry manure plus straw and other organics — it’s manure-based but not pure manure.
How much does bulk manure cost versus bags?
For the default 200 sq ft bed at 2 inches, bulk delivery runs about $103.95 versus $407 in 0.5 cu ft bags — bulk wins once you need more than about half a ton.
When should I apply manure — spring or fall?
Fall application gives composted manure time to fully integrate before spring planting; spring works too if the manure is already well-composted.
Does manure need to be watered in?
Yes — a good watering after application helps settle it in and start releasing nutrients into the soil.
How often should I add manure to garden beds?
Once a year is typical for most vegetable beds; test your soil every couple of years to avoid over-applying nutrients.
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Project
| Shape | — |
| Dimensions | — |
| Depth | — |
| Area | — |
| Material | — |
| Waste allowance | — |
Volume & weight (incl. waste)
| Cubic yards | — |
| Cubic feet | — |
| Weight | — |
| Tons (rounded up) | — |
Shopping list
| Bulk order | — |
| Bagged alternative (0.5 cu ft) | — |
| Estimated cost | — |
Notes
Estimate generated by materialcalculate.com. Assumes uniform depth and standard dry material densities. Confirm quantities with your supplier before ordering.