Farm Fertilizer Calculator
Quickly calculate fertilizer requirements for your farm: precise recommendations, transparent costs, and a plan you can act on today.
Sample estimate
12.5 acres · Maize · NPK Complex
Bags
37
Est. Cost
$1,332
Applications
3
Tell us about your field
Results update instantly as you adjust the inputs.
Recommended plan
Area
12.5 acres
Recommended Bags
62
47 × NPK Complex (50kg), 15 × Urea (50kg)
Estimated Cost
$2,112
total for field
Application Schedule
Basal Application · At planting
Incorporate 47 bags of NPK Complex into the soil before or at sowing.
First Top Dress · 4–6 weeks after planting
Apply 8 bags of Urea at early vegetative stage.
Second Top Dress · 8–10 weeks after planting
Apply 7 bags of Urea before flowering.
Plan notes
For maize targeting a standard yield of 2.4 tons/acre, NPK Complex (15-15-15) is applied at planting to cover phosphorus and potassium, and the nitrogen still missing is applied as top dressing in splits. Soil test data would refine this estimate further; treat these figures as a starting point for planning, not a substitute for a lab-based nutrient plan.
Next step: turn this cost into a season budget with the Farm Profit Calculator.
How calculations work
A transparent, four-step process turns your field details into a fertilizer plan you can trust.
Tell us your field
Enter your crop, field area, and target yield. We support acres and hectares out of the box.
We model nutrient demand
Published N-P₂O₅-K₂O application rates for your crop combine with your chosen fertilizer's actual composition.
Get bags, cost, and schedule
See exactly how many bags to buy, what it costs, and when to apply each round.
Read the plan notes
Short notes explain how the plan was built and why a soil test would refine it.
Why farmers use it
Every input is designed to save time and money at the point where decisions actually get made.
Reduce waste
Right-size every application so nutrients feed your crop instead of running off into the soil.
Improve yields
Match fertilizer timing and volume to your target yield for consistent, healthier growth.
Estimate costs
Know your fertilizer spend before you buy, with a clear bag count and total cost breakdown.
Compare scenarios
Test different crops, fertilizers, and field sizes side by side to find your best plan.
Frequently asked questions
How accurate are the fertilizer recommendations?
The calculator uses published N, P2O5 and K2O application rates from agronomy extension guidance for each crop, scaled to your target yield and area. Real recommendations vary by soil test, variety and region, so treat this as a solid planning starting point and not a replacement for a lab-based soil test.
How is the plan built?
The fertilizer you choose is applied at planting and sized to cover the crop's phosphorus and potassium needs. Any gap in those nutrients is filled with DAP or potash, and the nitrogen still missing is applied later as top dressing, usually urea, split into two applications.
Which units can I use for my field size?
You can switch between acres and hectares at any time using the toggle in the calculator. All outputs update instantly to match your selected unit.
Can I compare multiple crops or fertilizers?
Yes. Change the crop or fertilizer type and the results recalculate immediately, so you can compare scenarios before committing to a purchase.
Does the calculator account for soil type?
Not yet. Soil composition, pH and existing nutrient levels are the biggest drivers of real-world dosing. Use a soil test to adjust these figures.
Is my data stored anywhere?
No account is required. The crop, area and prices you enter are calculated in your browser and are not uploaded. The site counts anonymous feature use, as described in the privacy policy.