Coverage Area
5,000 sq ft🌿 Garden Planning Tool
Fertilizer & Water Mix Calculator
Calculate the right amount of fertilizer and water for your lawn, garden, or field.
Measurement system
1
Select Land Size
Enter the exact size.
SQ FT
🌾 5,000 SQ FT 0.115 ACRES
2
Fertilizer Analysis (N-P-K)
Numbers from your fertilizer bag.
This fertilizer contains 24% Nitrogen, 0% Phosphorus, and 11% Potassium.
3. Target Nitrogen Rate (lbs / 1,000 sq ft)
GAL
Land Size
0.115 acresFertilizer Needed
20.83 lbsWater Needed
2.50 gal 🌱
Grass Type
Adjusts N range and seasonal timing.
Fertilizer Needed
20.83 lbs total
Apply 20.83 pounds of 24-0-11 fertilizer to 5,000 square feet.
Water Mix
2.50 gallons total
Use 2.50 gallons of water to mix and apply your fertilizer.
Quick Reference Guide
Common Nitrogen Rates
0.25 Light feeding
0.5 Maintenance
0.75 Moderate
1.0 Heavy/common
1.5 Maximum
Fertilizer Examples
21-0-0 → 4.76 lbs / 1,000 sq ft
24-0-11 → 4.17 lbs / 1,000 sq ft
30-0-0 → 3.33 lbs / 1,000 sq ft
18-24-12 → 5.56 lbs / 1,000 sq ft
Tips
✅ Always follow the fertilizer label.
✅ Water after applying granular fertilizer.
✅ Apply early morning or late evening when possible.
How this fertilizer calculator works
Tell the calculator your land size (square feet or acres), the N-P-K percentages from your fertilizer bag, and the target pounds of nitrogen per 1,000 sq ft. The tool returns the total pounds of product needed, the per-1,000 sq ft rate, and the water volume for a sprayer mix.
How to use it
- Enter or slide the size of your lawn or garden.
- Type the N, P, and K percentages from the front of your fertilizer bag.
- Pick a target nitrogen rate (0.25 lb for light feeding up to 1.5 lb maximum).
- Read the total fertilizer and water values at the top of the page.
Frequently asked questions
How much fertilizer do I need per 1,000 sq ft?
It depends on the nitrogen percentage on the bag and your target nitrogen rate. Divide your target pounds of nitrogen per 1,000 sq ft by the nitrogen percentage (as a decimal) to get the pounds of product per 1,000 sq ft.
What do the N-P-K numbers mean?
N-P-K is the percentage by weight of Nitrogen, Phosphorus, and Potassium in the fertilizer. A 24-0-11 bag is 24% N, 0% P, and 11% K — the rest is filler and other nutrients.
When is the best time to apply fertilizer?
Early morning or late evening when temperatures are cooler reduces evaporation and leaf burn. Avoid applying before heavy rain, which can wash nutrients away.
Should I water before or after fertilizing?
For granular fertilizer, water after applying to dissolve the granules and move nutrients to the root zone. For foliar sprays, do not water immediately after — let the leaves absorb the spray first.
What is a typical nitrogen rate for lawns?
Common rates are 0.25 lb (light feeding) to 1.0 lb (heavy / common) of nitrogen per 1,000 sq ft per application. Maximum is around 1.5 lb. Always follow the label on your specific product.
Related calculators
How to use the Fertilizer Calculator
Calculate the correct amount of fertilizer for your lawn or garden based on area, grass type, and N-P-K requirements; convert between bag sizes and coverage areas; avoid over- or under-application.
Example workflow
Enter your lawn area in square feet or metres, select your grass type, and input your fertilizer's N-P-K values. The calculator returns the bag weight needed and application rate per area.
Common search topics
- fertilizer application rate
- N-P-K calculator
- lawn fertilizer amount
- garden nutrients
Regional use
Rates, costs, codes, and measurement standards vary by location. This calculator supports common use cases in:
- Fertilizer Calculator — United States
- Fertilizer Calculator — Texas
- Fertilizer Calculator — California
- Fertilizer Calculator — Florida
- Fertilizer Calculator — Georgia
- Fertilizer Calculator — Arizona
- Fertilizer Calculator — Canada
- Fertilizer Calculator — United Kingdom
- Fertilizer Calculator — Australia
Frequently asked questions
What do the N-P-K numbers on a fertilizer bag mean?
N is nitrogen (promotes leaf and green growth), P is phosphorus (supports root development), and K is potassium (overall plant health and stress resistance). The numbers are the percentage of each by weight.
How much fertilizer does a typical lawn need?
Most cool-season grasses need 2–4 lbs of nitrogen per 1,000 sq ft per year; warm-season grasses need 2–6 lbs. The right amount depends on your grass type, soil test results, and season.
Can I over-fertilize my lawn?
Yes. Excess nitrogen causes rapid leafy growth, weakens root systems, and can burn grass. It also runs off into waterways. Apply only what your soil test or grass type recommends.
Do I need a soil test before fertilizing?
A soil test is the most accurate way to know what your lawn actually needs. It costs around $15–30 and prevents wasted product. Contact your local cooperative extension office for a test kit.
When is the best time to fertilize?
Cool-season grasses respond best to fall and early spring applications. Warm-season grasses peak in late spring through summer. Avoid fertilizing during drought stress or extreme heat.
Related calculators
People also ask
What NPK ratio is best for a lawn?
For established lawns, a high-nitrogen formula like 30-0-4 or 32-0-6 is typical for green growth during the growing season. For new seeding or overseeding, a starter fertilizer with higher phosphorus (10-18-10 or similar) supports root establishment. In fall, a balanced or potassium-heavy formula (like 13-13-13 or 0-0-50) prepares the grass for winter dormancy. Always follow soil test recommendations over generic ratios.
What is slow-release vs fast-release fertilizer?
Fast-release (soluble) fertilizers deliver nitrogen quickly — you see green response in days — but are more prone to burning and leaching. Slow-release fertilizers (polymer-coated, sulfur-coated, or organic) feed over 6–12 weeks, require fewer applications, reduce burn risk, and are better for the environment. Most professional-grade lawn fertilizers contain a blend of both for quick initial response and sustained feeding.
How do I convert fertilizer rates from lbs/1,000 sq ft to lbs/acre?
Multiply by 43.56: a rate of 1 lb per 1,000 sq ft equals 43.56 lbs per acre. This is important when scaling from residential to agricultural applications. The unit converter on this site handles this calculation directly — enter your per-1,000 sq ft rate and convert to per-acre automatically.
Real-world scenarios
Treating a ½-acre lawn with a 28-0-3 fertilizer
A ½-acre lawn is 21,780 sq ft. At a target rate of 1 lb nitrogen per 1,000 sq ft and a 28-0-3 bag (28% nitrogen), you need 3.57 lbs of actual nitrogen, which requires 12.75 lbs of fertilizer per 1,000 sq ft — meaning about 278 lbs total, or roughly three 90-lb bags. Enter the lawn area and NPK values in the calculator to get the exact bag count for your specific product.
Fertilizing warm-season vs cool-season grass differently
Bermuda and Zoysia (warm-season) should not be fertilized until daytime temperatures consistently exceed 70°F — typically late April in the South, May further north. Fertilizing too early feeds weeds more than dormant warm-season grass. Fescue and bluegrass (cool-season) should receive their heaviest feeding in September–October, not spring, to build root reserves before winter.
Calibrating a spreader for accurate application
Spreader settings vary by brand and model — the bag's recommended setting is a starting point, not a guarantee. Calibrate by catching the output over a measured distance, weighing it, and comparing to target rate. Over-application by 20% is enough to burn a lawn in hot weather. The calculator's output in lbs gives you the target weight to verify against your spreader's actual delivery.