Last updated: June 19, 2026
Dry Matter Calculator
Creators
Dharmendra SinghReviewers
Creators
Dharmendra SinghReviewers
Quick Answer
The Dry Matter Calculator converts a food's as-fed nutrient percentage to a dry-matter basis using nutrient (DM) = nutrient (as-fed) × 100 ÷ (100 − moisture%). Dry matter is everything except water (dry matter% = 100 − moisture%), and the conversion factor is 100 ÷ dry-matter%. This matters because foods vary hugely in water content — dry kibble is ~10% moisture while canned food is ~78% — so their label (as-fed) percentages aren't comparable. For example, a canned food listing 10% protein at 78% moisture is actually about 45% protein on a dry-matter basis, often more than a kibble showing 26%. The same maths applies to protein, fat, fibre, ash or carbohydrate, and it is used in pet nutrition, livestock rationing, and forage testing to compare foods fairly.
To convert a nutrient to a dry-matter basis, divide its as-fed percentage by the dry matter fraction, which is one hundred minus the moisture percent. For example, a canned food with ten percent protein at seventy-eight percent moisture is about forty-five percent protein on a dry-matter basis.
Key Takeaways
- Dry matter % = 100 − moisture %; it's everything in a food except water
- Nutrient (DM) = nutrient (as-fed) × 100 ÷ (100 − moisture %)
- Wet and dry foods can't be compared by their labels — convert to a dry-matter basis first
- A canned food at 10% protein (78% moisture) is ~45% protein on a dry-matter basis
- The conversion factor is 100 ÷ dry-matter % — wetter foods have a bigger factor
- The maths is identical for protein, fat, fibre, ash or carbohydrate
Creators
Dharmendra SinghReviewers
Creators
Dharmendra SinghReviewers
Formula
Nutrient (DM basis) = Nutrient (as-fed) × 100 ÷ (100 − Moisture%)
Where:
- N_{DM}=Nutrient on a dry-matter basis(%)
- N_{af}=Nutrient on an as-fed basis (from the label)(%)
- M=Moisture content of the food(%)
Worked Examples
Dry kibble — crude protein
A dry dog food listing 26% crude protein at 10% moisture.
- 1Dry matter = 100 − 10 = 90%
- 2Conversion factor = 100 ÷ 90 = 1.11
- 3Protein (DM) = 26 × 1.11 = 28.89%
- 4So 26% as-fed is really ~28.9% protein on a dry-matter basis
- 5The small jump is because kibble has little water
Canned food — crude protein
A wet/canned food listing only 10% crude protein at 78% moisture.
- 1Dry matter = 100 − 78 = 22%
- 2Conversion factor = 100 ÷ 22 = 4.55
- 3Protein (DM) = 10 × 4.55 = 45.45%
- 4That 'low' 10% label is actually ~45% protein once water is removed
- 5This is why you must compare foods on a dry-matter basis
Fresh pasture — crude protein (livestock)
Fresh grazing grass at 80% moisture testing 4% crude protein as-fed.
- 1Dry matter = 100 − 80 = 20%
- 2Conversion factor = 100 ÷ 20 = 5.0
- 3Protein (DM) = 4 × 5.0 = 20%
- 4Fresh forage looks low in protein because it's mostly water
- 5On a dry-matter basis it's a respectable 20%
Grass hay — crude fibre
Grass hay at 12% moisture testing 32% crude fibre as-fed.
- 1Dry matter = 100 − 12 = 88%
- 2Conversion factor = 100 ÷ 88 = 1.14
- 3Fibre (DM) = 32 × 1.14 = 36.36%
- 4Hay is already low-moisture, so the change is small
- 5Use DM values to ration and balance forages consistently
Introduction
The Dry Matter Calculator converts a food's as-fed nutrient percentages (the numbers printed on the label) into a dry-matter (DM) basis — the only fair way to compare foods that contain different amounts of water. Because canned pet food is ~78% water and dry kibble is only ~10%, their labels aren't directly comparable: a wet food showing '10% protein' can actually contain *more* protein than a dry food showing '26%' once the water is removed. The formula is simple — nutrient (DM) = nutrient (as-fed) × 100 ÷ (100 − moisture%) — and it's used every day by pet owners, vets, and livestock nutritionists. Enter the moisture content and the as-fed nutrient % from the guaranteed analysis to see the true, comparable value. For related tools see our Dog Food Calculator, Dog Nutrition Calculator, and Feed Conversion Ratio Calculator.
What Is Dry Matter?
Dry matter is everything in a food *except* water — the protein, fat, fibre, carbohydrate, vitamins and minerals. Dry matter % = 100 − moisture %.
As-fed basis: nutrient percentages of the food exactly as it comes (water included) — what's on the label
Dry-matter basis: nutrient percentages after all water is mathematically removed
Moisture content is the difference between the two and varies enormously between foods
Removing water lets you compare a soup to a cracker fairly — both judged on their actual nutrients
Vets and nutritionists almost always discuss diets on a dry-matter basis
If you only ever remember one thing: you can't compare a wet food and a dry food using their labels. Convert both to a dry-matter basis first.
How to Convert As-Fed to Dry-Matter Basis
It's two short steps. First find the dry matter, then scale the nutrient up by the conversion factor.
- **Step 1 — Dry matter %:
** 100 − moisture %. (A 78% moisture food is 22% dry matter.)
- **Step 2 — Convert the nutrient:
** nutrient (as-fed) ÷ (dry matter % ÷ 100). Equivalently, × 100 ÷ (100 − moisture).
- **Conversion factor:
** 100 ÷ dry-matter %. The wetter the food, the bigger the factor.
- Example:
10% protein at 78% moisture → 10 × (100 ÷ 22) = 45.5% protein DM
Always convert *every* food you're comparing to the same (dry-matter) basis
Typical Moisture & Dry Matter of Common Foods
Use this quick reference if a moisture figure isn't on the label. Pet-food 'guaranteed analysis' usually lists maximum moisture.
| Food type | Typical moisture | Dry matter | Conversion factor (×) |
|---|---|---|---|
| Dry kibble | ~10% | ~90% | 1.11 |
| Semi-moist food | ~25% | ~75% | 1.33 |
| Fresh / gently cooked | ~70% | ~30% | 3.33 |
| Canned / wet food | ~78% | ~22% | 4.55 |
| Fresh pasture grass | ~80% | ~20% | 5.00 |
| Grass hay | ~12% | ~88% | 1.14 |
| Corn silage | ~65% | ~35% | 2.86 |
Values are typical averages — always use the actual moisture from the label or a forage test when you have it.
Why Wet and Dry Foods Can't Be Compared Directly
This is the single most important reason to use a dry-matter calculator. Consider two foods that look very different on the label:
| Food | Protein (as-fed) | Moisture | Protein (dry-matter) |
|---|---|---|---|
| Dry kibble | 26% | 10% | 28.9% |
| Canned food | 10% | 78% | 45.5% |
| Verdict | Kibble looks higher… | but it isn't | Canned wins on DM basis |
The canned food's '10%' protein is mostly hidden by water. On a dry-matter basis it actually delivers far more protein than the kibble — the opposite of what the labels suggest.
Where Dry-Matter Basis Is Used
Dry-matter conversion isn't just a pet-food trick — it's a foundation of animal nutrition and food science.
- **Pet nutrition:
** comparing kibble, canned, raw and fresh diets fairly
- **Livestock & dairy:
** rationing forages (hay, silage, pasture) on a dry-matter intake basis
- **Forage testing:
** lab reports give nutrients on both as-fed and dry-matter bases
- **Reading guaranteed analyses:
** AAFCO/FEDIAF labels are as-fed; vets convert to DM
- **Diet formulation:
** matching a nutrient target (e.g. % protein DM) across ingredients
Pair this with our Feed Conversion Ratio Calculator and [Dry Matter Intake] planning to balance livestock rations accurately.
Measuring Dry Matter in the Lab (Oven Method)
If you don't have a label moisture figure, dry matter is measured directly by drying a sample and weighing it.
Weigh a fresh (as-fed) sample — this is the wet weight
Dry it in an oven (e.g. 60–105°C) until the weight stops changing — the dry weight
Dry matter % = (dry weight ÷ wet weight) × 100
Moisture % = 100 − dry matter %
Microwave and Koster-tester methods give quick on-farm estimates
Over-drying protein-rich samples too hot can scorch them and slightly overstate dry matter — follow your lab's recommended temperature.
Glossary
Quick definitions for the terms used in this calculator:
| Term | Definition |
|---|---|
| Dry matter (DM) | Everything in a food except water; DM% = 100 − moisture%. |
| As-fed basis | Nutrient values of the food as it is eaten, water included (the label values). |
| Dry-matter basis | Nutrient values after water is mathematically removed, for fair comparison. |
| Moisture content | The percentage of a food that is water. |
| Guaranteed analysis | The label panel listing minimum/maximum nutrient and moisture percentages. |
| NFE | Nitrogen-free extract — the carbohydrate fraction estimated by difference. |
| Conversion factor | 100 ÷ dry-matter%, the multiplier from as-fed to dry-matter values. |
Quick Reference Card
Dry Matter Basis — Quick Reference
Quick reference • Dry Matter Calculator
DM% = 100 − moisture% · Nutrient(DM) = Nutrient(as-fed) × 100 ÷ (100 − moisture%)Valid range: Moisture 0–99% · factor = 100 ÷ DM% (kibble ≈1.11, canned ≈4.55)
Common Values
⚠ Watch Out
- •Never compare wet and dry foods using their as-fed labels
- •Use the actual label moisture, not a guess, when you can
- •Dry matter % can't be 100% if there's any moisture
- •A higher dry-matter % just means less water — not 'better'
Pro Tips
- →Convert every food you're comparing to the same dry-matter basis
- →Pet labels list 'Moisture (max)' in the guaranteed analysis
- →The factor (100 ÷ DM%) is the same for every nutrient in a food
- →For livestock, ration on dry-matter intake, not as-fed weight
FAQs
What is a dry matter basis and why does it matter?
A dry-matter (DM) basis expresses a food's nutrients after all its water has been mathematically removed. It matters because foods contain very different amounts of water — dry kibble ~10%, canned food ~78% — so their as-fed label percentages aren't comparable. Converting to a dry-matter basis lets you compare any two foods (wet vs dry, hay vs pasture) fairly, judging them on their actual nutrient content rather than how much water they happen to contain.
How do I convert as-fed to dry matter basis?
Use the formula: nutrient (dry matter) = nutrient (as-fed) × 100 ÷ (100 − moisture%). First work out the dry matter (100 − moisture%), then divide the as-fed nutrient by the dry-matter fraction. For example, a canned food with 10% protein at 78% moisture is 22% dry matter, so its protein on a dry-matter basis is 10 × 100 ÷ 22 ≈ 45.5%. This calculator does it for you instantly.
Why does my canned dog food show less protein than kibble?
Because the label is on an as-fed basis and canned food is mostly water (~78%). The protein is diluted by all that moisture, so the percentage looks small. Remove the water and the picture flips: a canned food at 10% protein and 78% moisture is about 45% protein on a dry-matter basis — often more than a kibble showing 26%. Always convert to a dry-matter basis before comparing wet and dry foods.
Where do I find the moisture content of a food?
On pet foods it's in the 'guaranteed analysis' panel, usually listed as 'Moisture (max)'. Dry foods are typically around 10%, semi-moist around 25%, and canned/wet foods around 75–82%. For forages and feeds, a lab forage test reports moisture and dry matter directly. If you can't find it, use a typical value from our moisture table as an estimate.
Does the type of nutrient change the calculation?
No — the maths is identical for protein, fat, fibre, ash or carbohydrate. The conversion factor depends only on the food's moisture, so you multiply any as-fed nutrient percentage by the same factor (100 ÷ dry-matter%). In this calculator the nutrient selector only changes the wording of the result; the number is computed the same way for every nutrient.
How is dry matter measured directly?
By drying. You weigh a fresh sample (wet weight), dry it in an oven until the weight stops changing (dry weight), then calculate dry matter % = (dry weight ÷ wet weight) × 100, with moisture being the remainder. Labs use precise oven methods; farmers often use microwave or Koster testers for quick on-farm dry-matter estimates of silage and forage.
Is a higher dry matter percentage better?
Not inherently — it just means less water. A high dry-matter food (like kibble) is more calorie- and nutrient-dense per gram, while a high-moisture food (like canned or fresh) provides hydration and is often more palatable. What matters is the nutrient profile on a dry-matter basis and whether it suits the animal's needs. Use dry matter to compare, not to judge a food as good or bad on its own.