Fertilizer Ratio Calculator
Calculate fertilizer needs based on NPK ratio, garden area, and application rate. Find out how many bags you need and the cost.
Inputs
%
%
%
sq ft
lbs N/1000 sq ft
lbs
$
Results
Total Fertilizer Needed
10 lbs
NPK Ratio10-10-10
Nitrogen (N) Delivered1 lbs
Phosphorus (P) Delivered1 lbs
Potassium (K) Delivered1 lbs
Bags Needed1
Total Cost$20
Cost per Sq Ft$0.02
Total Fertilizer Needed
10 lbs
How to Use This Calculator
- Start by filling in the input fields below. Results update instantly as you type, so you can experiment with different values to see how they affect the outcome.
- Nitrogen (N) — Nitrogen percentage from the fertilizer label (first number in NPK). Accepts values from 0 % to 50 % (default: 10 %).
- Phosphorus (P) — Phosphorus percentage from the fertilizer label (second number in NPK). Accepts values from 0 % to 50 % (default: 10 %).
- Potassium (K) — Potassium percentage from the fertilizer label (third number in NPK). Accepts values from 0 % to 50 % (default: 10 %).
- Garden Area — Total area to fertilize in square feet. Accepts values from 10 sq ft to 100,000 sq ft (default: 1,000 sq ft).
- Application Rate — Pounds of nitrogen to apply per 1000 sq ft. Typical lawn rate is 1 lb. Accepts values from 0.5 lbs N/1000 sq ft to 5 lbs N/1000 sq ft (default: 1 lbs N/1000 sq ft).
- Bag Weight — Weight of each fertilizer bag in pounds. Accepts values from 1 lbs to 100 lbs (default: 25 lbs).
- Cost per Bag — Price per bag of fertilizer. Accepts values from $1 to $200 (default: $20).
- Once all inputs are set, review your results in the Results panel. Here's what each output means:
- Total Fertilizer Needed — shown as a numeric value. This is the primary result of this calculator.
- NPK Ratio — your calculated result.
- Nitrogen (N) Delivered — shown as a numeric value.
- Phosphorus (P) Delivered — shown as a numeric value.
- Potassium (K) Delivered — shown as a numeric value.
- Bags Needed — shown as a numeric value.
- Total Cost — shown as a dollar amount.
- Cost per Sq Ft — shown as a dollar amount.
- Explore the related calculators below if you need deeper analysis or want to approach this topic from a different angle.
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