Find out exactly how much weed killer or weed-and-feed you need. Compare products, coverage, and costs.
Don't know your lawn size? Measure it with LotSite for free →
Units needed and cost by lawn size for popular products.
| Lawn Size | Scotts Weed & Feed | Scotts Weed & Feed | Roundup For Lawns | Spectracide Weed Stop |
|---|---|---|---|---|
| 2,000 sq ft | 1 × $28 = $28 | 1 × $54 = $54 | 1 × $22 = $22 | 1 × $15 = $15 |
| 4,000 sq ft | 1 × $28 = $28 | 1 × $54 = $54 | 1 × $22 = $22 | 1 × $15 = $15 |
| 5,000 sq ft | 2 × $28 = $56 | 1 × $54 = $54 | 1 × $22 = $22 | 1 × $15 = $15 |
| 8,000 sq ft | 2 × $28 = $56 | 1 × $54 = $54 | 2 × $22 = $44 | 2 × $15 = $30 |
| 10,000 sq ft | 3 × $28 = $84 | 1 × $54 = $54 | 2 × $22 = $44 | 2 × $15 = $30 |
| 15,000 sq ft | 4 × $28 = $112 | 2 × $54 = $108 | 3 × $22 = $66 | 3 × $15 = $45 |
The best weed control strategy is a thick, healthy lawn. Dense grass crowds out weeds naturally, reducing the need for chemical treatments. Mow high (3+ inches), fertilize on schedule, and water deeply but infrequently to promote strong root growth that outcompetes weeds.
When you do need weed killer, timing matters. Post-emergent herbicides (which kill existing weeds) work best when weeds are actively growing — typically spring and fall. Pre-emergent herbicides prevent weed seeds from sprouting and should be applied in early spring before soil temperatures reach 55°F.
Accurate lawn measurement prevents waste and ensures even coverage. Use LotSite to measure your grass area, then run it through the calculator above to buy exactly what you need.
Enter your address to get exact lawn square footage — free.
Also check out our fertilizer calculator and fertilizer timing guide