Free calculator
Lawn fertilizer calculator: how much product per area
With the US starting values (1,000 sq ft, a 32-0-4 bag, 1 lb per 1,000 sq ft of nitrogen per application, Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns, September), one application takes 3.13 lb of product: 0.3 (buy 1 bag) of 12.5 lb, $26.99; 4 feeds a year come to 12.5 lb. Type the three numbers on your own bag.
The area is shared: change it here and the other two calculators and the Pro plan use the same lawn.
Result
- Lawn area
- 1,000 sq ft
- Product per application
- 3.13 lb
- Spreader rate
- 3.13 lb per 1,000 sq ft
- Bags of 12.5 lb per application
- 0.3 (buy 1 bag)
- Cost per application
- $26.99
- Nutrients applied (N / P2O5 / K2O)
- 1 lb / 0 lb / 0.13 lb
- Per year, 4 applications
- 12.5 lb
- Cost per year
- $26.99
Product = area × nitrogen wanted ÷ (N% ÷ 100); P2O5 and K2O come along in the bag's proportions. Feeds per year for a cool-season lawn (northern us): 4, May, July (irrigated lawns), September and November; September and November matter most (Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns, high maintenance level, read 2026-09-20). Rates from university extension guides and product labels, each with its source and date: the label on the bag wins.
Pro puts the three results on one printable plan with a 12-month calendar.
Sod, seed and fertilizer as a shopping list with the cost, plus mowing, feeding, overseeding and aeration month by month for your climate. Printed or exported to Excel.
How much fertilizer per 1,000 sq ft? 3.13 lb of 32-0-4 at 1 lb of nitrogen
3.13 lb of 32-0-4, 4.17 lb of 24-0-6, 6.25 lb of 16-8-8, 10 lb of 10-10-10 or 16.7 lb of 6-2-4 per 1,000 sq ft deliver 1 lb per 1,000 sq ft of nitrogen (Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns, September): product = nitrogen wanted ÷ (N% ÷ 100). The phosphate and potash come along in the bag’s proportions.
| N-P-K | Per 1,000 sq ft | Per 5,000 sq ft | P2O5 per 1,000 sq ft | K2O per 1,000 sq ft |
|---|---|---|---|---|
| 32-0-4 | 3.13 lb | 15.6 lb | 0 lb | 0.13 lb |
| 24-0-6 | 4.17 lb | 20.8 lb | 0 lb | 0.25 lb |
| 16-8-8 | 6.25 lb | 31.3 lb | 0.5 lb | 0.5 lb |
| 10-10-10 | 10 lb | 50 lb | 1 lb | 1 lb |
| 6-2-4 | 16.7 lb | 83.3 lb | 0.33 lb | 0.67 lb |
Bags and cost for the lawn: the starting bag is 32-0-4, 12.5 lb at $26.99 (Scotts Turf Builder Lawn Food 12.5 lb), 4 feeds a year on the cool-season lawn (northern US) calendar. Bags are rounded up per feed and again for the year’s total, so the year can need fewer bags than feeds × bags per feed.
| Lawn | Per feed | Bags per feed | Cost per feed | Per year (4 feeds) | Bags per year | Cost per year |
|---|---|---|---|---|---|---|
| 1,000 sq ft | 3.13 lb | 1 | $26.99 | 12.5 lb | 1 | $26.99 |
| 5,000 sq ft | 15.6 lb | 2 | $53.98 | 62.5 lb | 5 | $134.95 |
| 10,000 sq ft | 31.3 lb | 3 | $80.97 | 125 lb | 10 | $269.90 |
The cost line makes it a lawn fertilizer cost calculator: bags × the price you typed. Every analysis at the calendar rates and for 1,000 sq ft to 10,000 sq ft is in how much fertilizer per 1,000 sq ft; at seeding use less nitrogen and a starter analysis: how much starter fertilizer per 1,000 sq ft. In the UK the 6-2-4 starting bag at 2.1 g per m² of N means 100 m² takes 3.5 kg per feed, 2 packs of 2.8 kg, £21.98; the year's 2 feeds are 7 kg, 3 packs, £32.97.
How it works
lb N wanted per 1,000 sq ft ÷ (N% ÷ 100) = lb of product per 1,000 sq ft, then × the area in thousands of sq ft (Purdue Turf, Calculating the pounds of fertilizer to apply). In the calculator: product = lawn area × nitrogen wanted ÷ (N% ÷ 100). The phosphate (P2O5) and potash (K2O) come along in the bag’s proportions: product × P% and product × K%. Bags = product ÷ bag weight, rounded up; cost = bags × the price you typed. Per year = product × the feeds the extension calendar schedules for your lawn type.
With the US starting values, a 32-0-4 bag needs 3.13 lb per 1,000 sq ft to deliver 1 lb per 1,000 sq ft of N, while a 10-10-10 bag needs 10 lb for the same nitrogen (and brings 1 lb of P2O5 with it). A 5,000 sq ft lawn takes 15.6 lb: 1.3 (buy 2 bags) of 12.5 lb. In the UK the starting values follow the Westland SafeLawn technical fact sheet: a 6-2-4 feed at 35 g/m² is 2.1 g per m² of N, so 100 m² takes 3.5 kg.
Feeds per year, from the extension calendars: cool-season lawn (northern us): 4 (May, July (irrigated lawns), September and November; September and November matter most; Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns, high maintenance level). warm-season lawn (southern us): 3 (Early May, June-July and before 15 August; none from September to green-up; Clemson HGIC 1216, Bermudagrass Yearly Maintenance Program). uk lawn: 2 (Late March to April (spring feed), September to October (autumn feed); an optional second summer feed no later than August; RHS, Lawn Care in Spring and Summer). The Pro plan puts them on the months.
Sources of the US starting values
- Formula: Purdue Turf, Calculating the pounds of fertilizer to apply (Reicher, Bigelow, Gibb, Latin, Richmond, 2009-01-28): "Desired rate in lbs N / 1000 sq ft ÷ % nutrient = Total fertilizer needed / 1000 sq ft", then multiply by the area; their example: 16-8-8 at 0.75 lb N/1,000 sq ft on 8,000 sq ft = 37 lb of product — https://turf.purdue.edu/calculating-the-pounds-of-fertilizer-to-apply-3/, read on 2026-09-20
- Nitrogen per application: Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns (Reicher and Throssell, 7/98), September: "Apply 1 lb. N/1000 ft2" — https://ag.purdue.edu/department/hla/extension/extension-publications-library/ext-pubs/ay-27-w.html, read on 2026-09-20
- Most in one application: Purdue Extension PPP-155, A Simple Procedure for Fertilizing Cool-Season Lawns: "Do not apply more than 1 pound of nitrogen per 1,000 square feet in a single application" — https://ag.purdue.edu/department/extension/ppp/resources/ppp-publications/mobile/ppp-155/a-simple-procedure-for-fertilizing-cool-season-lawns-your-guide-to-better-results.html, read on 2026-09-20
- Bag analysis: Scotts Turf Builder Lawn Food label (Grange Co-op listing): "32-0-4", N 32%, P2O5 0%, K2O 4% — https://www.grangecoop.com/scotts-turf-builder-32-0-4-lawn-food-5-000-sq-ft/, read on 2026-09-20
- Bag size: Scotts Turf Builder Lawn Food (Grange Co-op listing): "12.5 lb" bag, covers "5,000 sq ft" — https://www.grangecoop.com/scotts-turf-builder-32-0-4-lawn-food-5-000-sq-ft/, read on 2026-09-20
- Price per bag: Scotts Turf Builder Lawn Food 12.5 lb (Grange Co-op listing): $26.99 — https://www.grangecoop.com/scotts-turf-builder-32-0-4-lawn-food-5-000-sq-ft/, read on 2026-09-20
- Applications per year, cool-season lawn (northern us): Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns (Reicher and Throssell, 7/98), high maintenance level: May "0.75-1.0 lbs. N/1000 ft2", July "0.75 lbs. N/1000 ft2", September "1 lb. N/1000 ft2", November "1.5 lbs. N/1000 ft2" (four applications; the medium level skips July) — https://ag.purdue.edu/department/hla/extension/extension-publications-library/ext-pubs/ay-27-w.html, read on 2026-09-20
- Starting area: Convention: 1,000 sq ft, the area US extension seed and fertilizer rates are written per (Purdue Turf, Calculating the pounds of fertilizer to apply, 2009) — https://turf.purdue.edu/calculating-the-pounds-of-fertilizer-to-apply-3/, read on 2026-09-20
UK starting values (RHS feeding months, the Westland SafeLawn label) show their sources under each field when you switch region.
Rates from university extension guides and product labels, each with its source and date: the label on the bag wins. A soil test decides whether the lawn needs P and K at all; this is planning arithmetic, not agronomic advice.
Frequently asked questions
- How much fertilizer per 1,000 sq ft?
- Nitrogen wanted ÷ the bag's N%. At 1 lb per 1,000 sq ft of N (Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns, September), a 32-0-4 bag is 3.13 lb per 1,000 sq ft, a 10-10-10 bag 10 lb. Type your bag's numbers and the calculator shows your figure and the spreader rate.
- How much fertilizer for 5,000 sq ft?
- 15.6 lb of 32-0-4 per feed at 1 lb per 1,000 sq ft of N: 2 bags of 12.5 lb, $53.98. The year's 4 feeds are 62.5 lb, 5 bags, $134.95. Other analyses for the same nitrogen are in the table under the calculator.
- Is this a lawn fertilizer cost calculator?
- Yes: cost = bags (rounded up) × the price you type, per feed and per year. With the starting values one 12.5 lb bag at $26.99 covers 1,000 sq ft for the year's 4 feeds (12.5 lb), $26.99; 5,000 sq ft is 5 bags, $134.95. The starting price is one retailer's (Scotts Turf Builder Lawn Food 12.5 lb); type yours.
- How much fertilizer per 1,000 sq ft per year?
- 12.5 lb of 32-0-4 on the cool-season lawn (northern US) calendar: 4 feeds × 3.13 lb. Warm-season lawn (southern US): 3 feeds; UK lawn: 2 feeds. Pick the lawn type in the calculator and the per-year line follows.
- How much nitrogen should a lawn get per application?
- The US starting value is 1 lb per 1,000 sq ft (Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns, September), and Purdue Extension PPP-155, A Simple Procedure for Fertilizing Cool-Season Lawns says not more than 1 lb per 1,000 sq ft in a single application; the calculator flags a target above it. Purdue's calendar uses 0.75 to 1 lb in spring and summer and 1.5 lb for the late-fall feed after the last mowing.
- How many times a year should I fertilize?
- cool-season lawn (northern us): 4 (May, July (irrigated lawns), September and November; September and November matter most; Purdue Extension AY-27, Maintenance Calendar for Indiana Lawns, high maintenance level). warm-season lawn (southern us): 3 (Early May, June-July and before 15 August; none from September to green-up; Clemson HGIC 1216, Bermudagrass Yearly Maintenance Program). uk lawn: 2 (Late March to April (spring feed), September to October (autumn feed); an optional second summer feed no later than August; RHS, Lawn Care in Spring and Summer). The "lawn type" in the calculator picks the schedule; the per-year lines multiply one application by it.
- What do the three numbers on the bag mean?
- N-P-K: percent by weight of nitrogen, phosphate (P2O5) and potash (K2O). A 32-0-4 bag is 32% nitrogen and 4% potash, so 100 lb of it carries 32 lb of N. The calculator works from N and reports the P2O5 and K2O that come with it, so a soil test can tell you whether that is what the lawn needs.
- How much starter fertilizer per 1,000 sq ft?
- 4.69 lb of 16-8-8 or 7.5 lb of 10-10-10 at Penn State Extension's 0.75 lb per 1,000 sq ft midpoint. Same arithmetic: type the starter bag's analysis (starter fertilizers carry more phosphate for roots) and the nitrogen rate your extension guide or the bag gives for seeding; the product per 1,000 sq ft and the P2O5 applied appear. Check that the P is wanted: a soil test tells you whether the lawn needs phosphorus at all.
- Does the calculator work in g/m² for the UK?
- Yes. Switch the region to UK / metric: the starting bag is the Westland SafeLawn technical fact sheet (6-2-4 at 35 g/m², 2.1 g per m² of N), so 100 m² takes 3.5 kg per feed; RHS schedules a spring feed and an autumn feed. Type any other bag's analysis and label rate.
Guides
- How much starter fertilizer per 1,000 sq ft? (10-10-10, 16-8-8, 20-10-10 at seeding)
Starter fertilizer at seeding: Penn State's nitrogen range as lb of 10-10-10, 16-8-8 and 20-10-10 per 1,000 sq ft, and for lawns of 1,000 to 10,000 sq ft.
- How much fertilizer per 1,000 sq ft? (pounds of 32-0-4, 24-0-6, 16-8-8 and 10-10-10 at 1 lb of nitrogen)
Pounds of fertilizer per 1,000 sq ft at 1 lb of nitrogen, by N-P-K from 32-0-4 to 10-10-10; bags and cost for a year on 1,000 to 10,000 sq ft; UK per m².