Nitrogen fertilizer cost per pound is the true apples-to-apples comparison between fertilizer products. Because anhydrous ammonia, urea, UAN solution, DAP, and MAP all have different nitrogen concentrations, their per-ton or per-gallon prices can be misleading. This calculator converts any fertilizer price to a standard $/lb N basis for direct comparison.
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Cost Per Pound of Nitrogen — Comparison
| Fertilizer | N% | Your Price | $/lb N | vs Cheapest |
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How to Compare Fertilizer Cost per Pound of Nitrogen
Fertilizer labels list guaranteed analysis as a percentage (e.g., urea = 46-0-0 means 46% N). Converting from dollars per ton to dollars per pound of actual nitrogen lets you compare any two products on the same basis regardless of packaging or form.
Dry Fertilizer Formula ($/ton)
For dry fertilizers priced per ton: $/lb N = price per ton ÷ (N% × 20). The denominator is lbs of N per ton. Urea at 46% N contains 920 lbs N per ton. At $450/ton, urea is $0.49/lb N.
Liquid Fertilizer Formula ($/gallon)
Liquid fertilizers (UAN 28, UAN 32, liquid 10-34-0) are priced per gallon. Lbs of N per gallon = N% × density (lbs/gal). UAN 28% has density 10.6 lbs/gal, so 0.28 × 10.6 = 2.97 lbs N/gal. At $0.50/gal, that is $0.17/lb N — seemingly cheap, but require more gallons per acre than dry urea.
Hidden Costs to Consider
Raw $/lb N comparisons miss application efficiency. Anhydrous ammonia applied in fall can have 10-15% denitrification or leaching losses by planting. Surface-applied urea without rain incorporation can lose 15-25% to volatilization. UAN injected into the soil has minimal loss. Adjust effective $/lb N by dividing by application efficiency (e.g., 85% recovery = divide price by 0.85).
FAQ
Is this fertilizer calculator free?
Yes, completely free with no signup required. All calculations run in your browser.
What is the cheapest source of nitrogen for crops?
Anhydrous ammonia (82% N) has historically been the cheapest cost per unit of N when considering the high nitrogen concentration. At equal application efficiency, it typically costs 20-30% less per lb N than urea (46% N) and 30-40% less than UAN 32% (32% N). However, equipment cost, handling requirements, and application timing affect the real-world comparison.
How do I calculate cost per lb of nitrogen?
Divide the fertilizer price per ton by (nitrogen percentage × 20). For example, urea at $500/ton with 46% N: $500 ÷ (0.46 × 2000) = $500 ÷ 920 = $0.54/lb N. For liquid fertilizers (per gallon), multiply density × N% × 8.33 lb/gal to get lbs N per gallon, then divide price per gallon by lbs N per gallon.
What is the difference between DAP and MAP?
DAP (18-46-0) and MAP (11-52-0) both provide phosphate. DAP has more N (18%) but less P2O5 (46%); MAP has less N (11%) but more P2O5 (52%). For cost comparison of phosphate, compare $/lb P2O5. For nitrogen contribution, DAP is usually cheaper per lb N than MAP.
Should I use the N analysis on the bag or guaranteed analysis?
Always use the guaranteed analysis on the fertilizer tag or label. Actual N content can vary slightly between products. Urea is typically 46% N, anhydrous ammonia is 82% N, DAP is 18% N, MAP is 11% N, and UAN 28% solution is 28% N by weight.