US Garden Fertilizer
US Garden Fertilizer — US reference tool.
About US Garden Fertilizer
US fertilizer bags are labelled with an N-P-K analysis, and the first number is the percentage of the bag weight that is actual nitrogen. Lawn feeding rates are quoted in pounds of nitrogen per 1000 square feet, not pounds of bag, so you have to divide by that percentage to get the amount of product to spread. A 24-0-4 bag is only 24 percent nitrogen, so delivering one pound of N over 1000 square feet takes about 4.2 pounds of product. This calculator converts your area to thousands of square feet, multiplies by the nitrogen target, divides by the bag analysis, and reports both the total product weight and the per-1000-square-foot figure you dial into a spreader.
Formulas
Nitrogen required
lb N = target lb per 1000 sq ft x (area / 1000)
- target
- Recommended nitrogen rate per application
Product required
lb product = lb N / (N% / 100)
- N%
- First number in the bag's N-P-K analysis
Bags
Bags = ceiling(lb product / bag weight)
Worked example
With the default values below, US Garden Fertilizer returns Fertilizer Needed of 20.8. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Area to feedaccepts 1–500,000 sq ft
- 5,000 sq ft
- Nitrogen target per applicationaccepts 0.1–2 lb N / 1000 sq ft
- 1 lb N / 1000 sq ft
- First number on the bag (% N)accepts 1–100 %
- 24 %
- Bag weightaccepts 1–200 lb
- 40 lb
Results
- Fertilizer Needed
- 20.8 lb
- Bags to Buy
- 1
- Spreader Setting
- 4.17 lb / 1000 sq ft
- Actual Nitrogen Applied
- 5.00 lb N
Step by step
- 1Values used
- 2Nitrogen required
- 3Product required
- 4Bags
- 5Fertilizer Needed= 20.8 lb
- 6Bags to Buy= 1
- 7Spreader Setting= 4.17 lb / 1000 sq ft
- 8Actual Nitrogen Applied= 5.00 lb N
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 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.
- A planning estimate only. Fertilizer application rates are regulated in some US states and municipalities, with seasonal blackout dates and phosphorus restrictions near water. Always follow the label directions on your product and check your state or county extension guidance before applying.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
A planning estimate only. Fertilizer application rates are regulated in some US states and municipalities, with seasonal blackout dates and phosphorus restrictions near water. Always follow the label directions on your product and check your state or county extension guidance before applying.
Frequently Asked Questions
Why is the product weight so much higher than the nitrogen weight?
Only the first number in the N-P-K analysis is nitrogen; the rest of the bag is phosphorus, potassium, filler and carrier. A 24-0-4 product is 24 percent nitrogen, so 1 pound of actual N requires about 4.2 pounds of product.
How much nitrogen should I apply at once?
Most US cooperative extension programmes suggest no more than 1 pound of nitrogen per 1000 square feet per application, and 0.5 pounds for quick-release products, spread across the growing season. Applying more in one pass risks burning the turf and leaching nitrogen into groundwater.
Does this work for slow-release fertilizer?
The arithmetic is identical, since it depends only on the labelled nitrogen percentage. Slow-release products simply let you apply toward the higher end of the recommended range safely, because the nitrogen becomes available over weeks instead of days.
Related Calculators
United States specifics
- Currency
- $ USDUS Dollar
- Region
- North America
- Country code
- US
- Amounts look like
- $1,234,567.89
- Dates look like
- Mar 9, 2026
- Units
- imperialWeek starts Sunday
In United States, imperial units are in everyday use.
Results on this page are expressed in USD (US Dollar). Figures are estimates for general planning — confirm current rates and thresholds with the relevant United States authority before relying on them.