Compost and Organic Amendment Converter (Dry Matter, Volume, Weight)

Q: "I do not know the bulk density."

"Bulk density is optional. The tool still shows every result that can be calculated at that point. Only the volume-to-weight part stays unavailable, with a reason shown on the card."

Q: "I handle compost by cubic meters."

"Choose Enter by Volume and enter m3, L, or yd3. Add bulk density to get weight, and add moisture to get dry matter at the same time."

Q: "Can I work backward from a dry matter target?"

"Yes. Choose Enter by Weight and Dry Matter Basis, then enter the dry matter target. Add moisture to get as-applied weight, and add bulk density to reach volume."

Q: "How should I read 60% moisture?"

"This tool treats moisture on a wet basis. A moisture content of 60% means dry matter is 40%."

Q: "Which units are supported?"

"Weight supports t, kg, US ton, and long ton. Volume supports m3, L, and yd3. Bulk density supports kg/m3, t/m3, and lb/yd3. Area supports ha, a, m2, and acre. Per-area output is shown mainly in t/ha, tDM/ha, and m3/ha."

Convert dry matter, as-applied weight, and volume from moisture content and bulk density.

Values can change widely with material type, moisture, and compaction. Use field measurements whenever possible.

Enter only the application amount and the tool still shows every result it can Add moisture content to unlock dry matter and as-applied weight conversion Add bulk density to connect volume and weight Add area to expand the result into t/ha, tDM/ha, and m3/ha

How to use

Choose either Enter by Weight or Enter by Volume, then enter the application amount.
Add moisture content to reveal dry matter or as-applied weight results.
Add bulk density to convert between volume and weight.
Add application area to show t/ha, tDM/ha, and m3/ha.

Quick examples

Example A: Start from cubic meters and get as-applied and dry matter weight

Input:

Volume mode, 20 m3, bulk density 600 kg/m3, moisture 50%, application area 0.5 ha

Output:

As-applied weight 12.0 t, dry matter 6.0 tDM, volume 20.0 m3, 24.0 t/ha, 12.0 tDM/ha, 40.0 m3/ha

Example B: Work backward from a dry matter target

Input:

Weight mode, dry matter basis, 4.0 tDM, moisture 60%, bulk density 700 kg/m3, application area 0.4 ha

Output:

As-applied weight 10.0 t, dry matter 4.0 tDM, volume 14.3 m3, 25.0 t/ha, 10.0 tDM/ha, 35.7 m3/ha

Reference values

These values are optional starting points only. They are examples, not guaranteed standards.

Example for screened compost

Around 1000 lb/yd3 (about 593 kg/m3) is sometimes used as an example near 50% moisture.

OSU Extension Service

Example for very wet compost

Very wet compost can exceed 1500 lb/yd3 (about 890 kg/m3).

OSU Extension Service

General range example

A published example mentions roughly 500-700 kg/m3 for compost at 35-55% moisture.

MDPI

Prefer field measurements

Particle size, packing, and moisture can shift density a lot, so direct field measurement is better when available.

Use local measurements first

Glossary

As-applied weight: The real weight including water. This is the amount used in spreading and transport.
Dry matter weight: The weight after removing water. This is useful when comparing analyses or targeting dry matter rates.
Moisture content (wet basis): The share of water in the as-applied material. If moisture is 60%, dry matter is 40%.
Bulk density: The as-applied weight per unit volume. It connects volume-based handling and weight-based planning.

Formulas

The tool keeps internal calculations in kg, m3, and ha, then formats them for display.

Dry matter fraction = 1 - moisture content
Dry matter weight = as-applied weight × dry matter fraction
As-applied weight = volume × bulk density
Per-area rate = amount ÷ area

Frequently asked questions

I do not know the bulk density.

Bulk density is optional. The tool still shows every result that can be calculated at that point. Only the volume-to-weight part stays unavailable, with a reason shown on the card.

I handle compost by cubic meters.

Choose Enter by Volume and enter m3, L, or yd3. Add bulk density to get weight, and add moisture to get dry matter at the same time.

Can I work backward from a dry matter target?

Yes. Choose Enter by Weight and Dry Matter Basis, then enter the dry matter target. Add moisture to get as-applied weight, and add bulk density to reach volume.

How should I read 60% moisture?

This tool treats moisture on a wet basis. A moisture content of 60% means dry matter is 40%.

Which units are supported?

Weight supports t, kg, US ton, and long ton. Volume supports m3, L, and yd3. Bulk density supports kg/m3, t/m3, and lb/yd3. Area supports ha, a, m2, and acre. Per-area output is shown mainly in t/ha, tDM/ha, and m3/ha.

Notes

Moisture content and bulk density vary widely with feedstock, particle size, compaction, and storage conditions.
Use this converter as an estimate. Field measurements of moisture and bulk density are preferable whenever possible.
Reference values are only input aids. Do not treat them as guaranteed standards.