Know Your Numbers
Fertilizer Calculator
Enter the numbers from your fertilizer bag and get exact application rates. No more guessing how much to put down.
Your Lawn Size
Desired Nitrogen
Pre-Emergent: Dry or Wet
Pick your application style. Dry is easiest (spreader + water-in). Wet gives tighter control using WDG in a sprayer.
Easy Combo Products (Fertilizer + Pre-Emergent)
Scotts Halts 30-0-4 (Pendimethalin 1.29%): One 13.35 lb bag covers 5,000 sq ft. Spread on a dry lawn, then water in with 1/4–1/2 inch within 2–3 days.
Barricade Plus Lawn Food 18-0-4 (Prodiamine 0.426%): Granular combo option with spreader settings and homeowner bag sizes (5,000 and 11,100 sq ft coverage options shown by manufacturer).
Practical workflow: apply dry on a calm day, lightly overlap passes, then irrigate. Don't use pre-emergent where you plan to seed.
Source patterns used here: manufacturers typically frame dry products as simple spreader + water-in workflows, while WDG examples emphasize weighing grams, split apps, and immediate irrigation.
Your Fertilizer Bag
Read the three big numbers on the front of your bag. They represent N-P-K (Nitrogen, Phosphorus, Potassium) as percentages.
Common fertilizers:
Enter your lawn size, desired nitrogen,
and fertilizer N-P-K to see results.
How the math works
Rate = Desired N ÷ (N% ÷ 100)
Total = Rate × (Lawn Size ÷ 1,000)
Coverage = (Bag Weight ÷ Rate) × 1,000
Example: You want 0.75 lb N from a 24-0-6.
0.75 ÷ 0.24 = 3.13 lbs per 1,000 sq ft.