Calculator · post-harvest
Water removal calculator
Estimates the water that leaves a lot, and the mass left behind, when it is dried from one moisture content to another.
Result
Enter values to see a result.
Formula & assumptions
Dry-matter mass
formula v1.0.0 · calc v1 · reviewed 2026-07-16DM = M × (100 − M_wb) ÷ 100
Applies to: Any commodity with a stated wet-basis moisture.
Assumptions
- The mass entered is the whole lot, including its water.
- Dry matter is conserved by drying — this quantity is what every downstream drying result is anchored to.
Limitations
- Unit-agnostic: the output carries whatever mass unit the input used.
Scope
Arithmetic on the numbers entered. It does not replace representative sampling or a calibrated, correctly-referenced moisture meter, and it cannot detect that an input was wrong.
Sources: Food and Agriculture Organization of the United Nations (FAO) (opens in a new tab), USDA Agricultural Research Service (ARS) (opens in a new tab)
Water mass from wet-basis moisture
formula v1.0.0 · calc v1 · reviewed 2026-07-16W = M × M_wb ÷ 100
Applies to: Any commodity with a stated wet-basis moisture.
Assumptions
- Wet basis: the percentage is denominated on total mass.
Limitations
- The complement of dry-matter mass; the two always sum to the total mass entered.
Scope
Arithmetic on the numbers entered. It does not replace representative sampling or a calibrated, correctly-referenced moisture meter, and it cannot detect that an input was wrong.
Sources: Food and Agriculture Organization of the United Nations (FAO) (opens in a new tab), USDA Agricultural Research Service (ARS) (opens in a new tab)
Mass after drying to a target moisture
formula v1.0.0 · calc v1 · reviewed 2026-07-16M₁ = M₀ × (100 − M₀_wb) ÷ (100 − M₁_wb)
Applies to: Commodities dried without a change of identity (grain, seed, dried produce).
Assumptions
- Dry matter is conserved: only water leaves. This is the whole derivation — M₀ × DM₀ = M₁ × DM₁.
- Drying only; the target moisture must not exceed the initial moisture.
Limitations
- Ideal mass balance. Real drying also loses solids — as fines, dust, broken material, and handling loss — so the actual outturn is typically lower than this figure.
- Says nothing about how to dry: no temperature, airflow, time, or energy is implied or computed.
Scope
Not a drying recommendation. It computes what the mass would be if only water were removed; it does not prescribe drying conditions, which depend on the commodity, equipment, and end use, and which the wrong choice of can damage a lot irreversibly.
Sources: Food and Agriculture Organization of the United Nations (FAO) (opens in a new tab), USDA Agricultural Research Service (ARS) (opens in a new tab), Iowa State University Extension and Outreach (opens in a new tab)
Water removed by drying to a target moisture
formula v1.0.0 · calc v1 · reviewed 2026-07-16ΔW = M₀ × (M₀_wb − M₁_wb) ÷ (100 − M₁_wb)
Applies to: Commodities dried without a change of identity (grain, seed, dried produce).
Assumptions
- Dry matter is conserved; the difference between initial and final mass is water only.
Limitations
- The water that must leave for the lot to reach the target. Not the mass the lot will actually lose, which also includes solids as fines and handling loss.
- No drying time or energy is implied: that requires an air-condition model this platform does not publish.
Scope
Not a drying recommendation and not an energy estimate. It states a mass of water, not how to remove it.
Sources: Food and Agriculture Organization of the United Nations (FAO) (opens in a new tab), USDA Agricultural Research Service (ARS) (opens in a new tab), Iowa State University Extension and Outreach (opens in a new tab)
Moisture: dry basis → wet basis
formula v1.0.0 · calc v1 · reviewed 2026-07-16M_wb = M_db ÷ (100 + M_db) × 100
Applies to: Any commodity whose moisture is reported on a stated basis.
Assumptions
- Water and dry matter are the only components; nothing else is present or is being tracked.
Limitations
- A conversion between two denominators, not a measurement.
- The result approaches but never reaches 100%, which is the definitional ceiling of wet basis.
Scope
Arithmetic on the numbers entered. It does not replace representative sampling or a calibrated, correctly-referenced moisture meter, and it cannot detect that an input was wrong.
Sources: Food and Agriculture Organization of the United Nations (FAO) (opens in a new tab), USDA Agricultural Research Service (ARS) (opens in a new tab)
About this tool
- A mass balance in which only water leaves. Real drying also loses solids as fines, dust, and broken material, so the actual outturn is typically below the final mass shown.
- Nothing here describes how to dry: no temperature, airflow, time, or energy is implied or computed.
- Dry matter is unchanged by drying, so the dry-matter figure below anchors every other number on this page.
Educational reference — not a prescription
Not a drying prescription and not an energy estimate. It states what the masses would be if only water were removed; drying conditions depend on the commodity, the equipment, and the end use, and the wrong ones can damage a lot irreversibly.
- These calculators are for education and reference. The quality of any result depends entirely on the accuracy of the values you enter.
- Local agronomic conditions, legal requirements, product labels, and professional advice may override a general calculation.
- Results are not pesticide, fertilizer, irrigation, or veterinary prescriptions, and are not a substitute for advice from a qualified agronomist or your local extension service.