Slurry, Manure, N & P Calculator
Based on RB209 — M3 & UK gallons
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Slurry & Manure N + P Calculator UK – RB209 2025 Values
Instantly calculate total slurry volume (m³ + UK gallons), solid manure (tonnes), and exact Nitrogen & Phosphorus output from your livestock – using official AHDB RB209 2025 figures.
How to Use the Slurry & Manure N + P Calculator
- Add livestock types – unlimited rows for mixed herds
- Enter number of head and weeks housed (default 26)
- Adjust slurry vs manure % using the slider (e.g. 70 % slurry / 30 % FYM)
- Instant results update for volume (m³ + gallons), solid manure (tonnes), total N and P (kg/year)
- Download professional landscape PDF for records, grant applications or NVZ audits
Official RB209 2025 Nutrient & Volume Values
These are the exact figures used in the calculator (AHDB RB209 9th Edition – 2025 update).
| Livestock Type | Weekly Slurry (m³/head) | Weekly Manure (t/head) | N (kg/head/year) | P₂O₅ (kg/head/year) |
|---|---|---|---|---|
| Dairy cow (>9000 L) | 3.1 | 0.9 | 100 | 19 |
| Dairy cow (6000–9000 L) | 2.8 | 0.8 | 100 | 19 |
| Dairy cow (<6000 L) | 2.5 | 0.7 | 100 | 19 |
| Dairy heifer (13 mo – 1st calf) | 1.8 | 0.5 | 45 | 8.3 |
| Beef suckler cow (>500 kg) | 2.3 | 0.65 | 52 | 9.6 |
| Steer/heifer (>25 mo) | 1.6 | 0.45 | 45 | 8.3 |
| Ewe + lamb (<60 kg) | 0.07 | 0.05 | 9 | 1.0 |
| Other / default | 0.7 | 0.2 | 9 | 1.0 |
Full 20+ categories available inside the calculator
Frequently Asked Questions
Do I need to adjust for dirty water or rainfall?
Yes – add 10–20 % buffer to slurry volume. The calculator gives base production; real volume is usually higher.
Why is N & P calculated over 52 weeks but volume only for housed weeks?
NVZ rules use annual nutrient excretion (52 weeks) for 170 kg/ha limit, but slurry/manure is only produced when housed.
Can I export manure to reduce my N loading?
Yes – deduct exported N/P using receipts. Pair with our NVZ Compliance Checker for full records.