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Urea Requirement Calculator

Work out urea requirement instantly with clear inputs, formula shown and shareable results.

About Urea Requirement Calculator

Urea is 46% nitrogen, so every kilogram of N needs 1/0.46 = 2.174 kg of urea. Splitting the total across two or three top dressings matches supply to crop demand and cuts losses to volatilisation and leaching. Indian urea bags are 45 kg.

Formulas

Urea from nitrogen

Urea (kg) = N required (kg) / N content fraction

Split dose

Per application = total urea / number of splits

Worked example

With the default values below, Urea Requirement Calculator returns Urea Required of 260.87. Change any input above and every figure here is recalculated in your browser.

Inputs used

Nitrogen Requiredminimum 0 kg N
120 kg N
Nitrogen Content Of Ureaaccepts 1–100 %
46 %
Number Of Split Applicationsaccepts 1–10
3
Bag Sizeminimum 1 kg
45 kg

Results

Urea Required
260.87
Urea Per Split Application
86.96
Bags Required
5.80
Bags To Buy
6

Step by step

  1. 1Values used
  2. 2Urea from nitrogen
  3. 3Split dose
  4. 4Urea Required= 260.87
  5. 5Urea Per Split Application= 86.96
  6. 6Bags Required= 5.80
  7. 7Bags To Buy= 6

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • Excess nitrogen leaches to groundwater as nitrate and is lost to air as ammonia and nitrous oxide. Apply only the soil-test recommended rate.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Excess nitrogen leaches to groundwater as nitrate and is lost to air as ammonia and nitrous oxide. Apply only the soil-test recommended rate.

Frequently Asked Questions

Why split the nitrogen dose?

Urea converts to nitrate quickly and nitrate leaches. Applying it in two or three doses timed to peak uptake raises recovery from around 30-40% to 50-60%.

Should urea be broadcast on the surface?

Incorporating or irrigating it in immediately cuts ammonia volatilisation losses, which can reach 20-30% from urea left on a warm dry surface.

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