Dry Matter Calculator — DM% and Moisture Content
Calculate the dry matter (DM) content of a sample from its fresh weight and dry weight, or from its known moisture percentage. Useful for forage testing, food science, soil analysis and any lab work that compares results on a dry-weight basis.
Input method
g
g
Percentage of fresh weight that is dry matter
- 1
Dry weight ÷ Fresh weight
20 ÷ 100 = 0.2 - 2
Dry matter content
0.2 × 100 = 20
How does this calculator work?
Dry matter % = (dry weight ÷ fresh weight) × 100. Weigh the fresh sample, dry it to constant mass in an oven, weigh again, and divide. Moisture % = 100 − DM%. Feed and food nutritional values should always state whether they are expressed on a fresh-weight or dry-weight basis, as results can differ substantially.
Formula
How this is calculated
Dry matter content describes what fraction of a fresh (wet) sample remains after all moisture is removed. You measure the sample before drying (fresh weight) and after drying to constant mass in an oven at around 60–105 °C (dry weight). The dry matter percentage is simply: DM% = (dry weight ÷ fresh weight) × 100. Moisture content is the complement: 100 − DM%.
Alternatively, if a moisture percentage is already known from a lab report, you can enter that directly and the calculator derives the dry weight and water content from the fresh weight. This is common when using a hay moisture meter or grain moisture sensor.
Results are reported both on a fresh-weight basis (DM% of the original sample) and on a dry-weight basis (what proportion of the non-water portion is solids — useful when comparing feeds or foods with very different water contents). Always state which basis you are using when reporting DM values, as "50% protein on a dry-matter basis" means something very different from "50% protein on a fresh-weight basis".
Frequently asked questions
Animals consume feed for its dry-matter nutrients — energy, protein, fibre — not for its water. Two hay bales may look identical by weight but one may contain 85% DM while the other is only 70% DM after rain. Comparing feeds on a dry-matter basis lets you accurately assess nutritional value and avoid over- or under-feeding.
Fresh-weight basis expresses a value (DM, protein, ash) as a percentage of the total sample including water. Dry-weight basis expresses it as a percentage of just the dry fraction. A sample with 20% DM on a fresh-weight basis has 100% DM on a dry-weight basis (the dry fraction IS the dry matter). Protein or mineral concentrations can look very different depending on which basis is used, so always state which you mean.
The standard method is to place a weighed sample in a forced-air oven at 60–65 °C (for forages) or 100–105 °C (for grain and most food-science work) until the weight stabilises (usually 24–48 hours). Microwave-drying methods are faster but require calibration. The final constant weight is the dry weight.
Also known as
TG we-Calculate Editorial Team. (2026). Dry Matter Calculator — DM% and Moisture Content [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/dry-matter-calculator
TG we-Calculate Editorial Team. "Dry Matter Calculator — DM% and Moisture Content." TG we-Calculate. 2026. https://we-calculate.com/calculator/dry-matter-calculator.
TG we-Calculate Editorial Team, "Dry Matter Calculator — DM% and Moisture Content," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/dry-matter-calculator
@misc{wecalculate_dry_matter_calculator, title = {Dry Matter Calculator — DM% and Moisture Content}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/dry-matter-calculator}}, year = {2026}, note = {TG we-Calculate} }
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