Sherwin-Williams vs Lowe's Paint Calculator: Which Gives Better Estimates in 2026?
Lowe's paint calculator gives the better estimate for most DIYers: it lets you edit the coverage rate, takes fuller room dimensions including moulding, and uniquely estimates man-hours as well as gallons. Sherwin-Williams' calculator is faster and matches gallons to its own products, but it assumes one coat at ~400 sq ft/gal and prices nothing. Neither brand calculator will tell you what the job costs — that's a different tool.
Quick answer: Sherwin-Williams assumes 'one gallon will cover approximately 400 square feet' with results calculated for one coat (verbatim, checked 2026-10); Lowe's states 'paint usually is applied at 350 to 400 square feet per gallon (primer at 200 to 300)' and lets you edit both fields. Lowe's also outputs man-hours; Sherwin-Williams outputs product quantity only. Both are free with no signup. Neither estimates dollars — use a cost calculator for that.
Sherwin-Williams vs Lowe's: which paint calculator is better?
For control and honesty about coverage, Lowe's; for speed and brand-matched product amounts, Sherwin-Williams. Here is the feature-by-feature comparison from our hands-on check in October 2026.
| Feature | Sherwin-Williams | Lowe's |
|---|---|---|
| Coverage assumption | "It assumes one gallon will cover approximately 400 square feet" — fixed, and results are for one coat (verbatim, checked 2026-10) | "Paint usually is applied at 350 to 400 square feet per gallon (primer at 200 to 300)" — editable primer and finish fields (2026-02 snapshot of the live page) |
| Coats handling | One coat per calculation; run it twice for two coats | No coats field — you adjust the coverage inputs instead |
| Inputs | Total height and width in feet, window and door counts (doors sized 3'×7', windows 3'×5') | Length, width and height in feet and inches; doors, windows, moulding width; primer and finish coverage rates |
| Output | Gallons of product | Gallons + estimated man-hours for the job |
| Dollar cost | Not provided | Not provided |
| Signup | None | None |
| Modes | Quick, Custom and Deck calculation | One room/space form (walls and ceiling area) |
Which calculator gives better estimates?
Lowe's, for most people — for three verifiable reasons. Its coverage band starts at 350 sq ft/gal, the safer planning number for real walls, and you can override it to match your actual paint's label. Its inputs are finer (feet plus inches, moulding). And it's the only one of the two that estimates man-hours — the number that actually predicts a weekend's worth of work. Sherwin-Williams wins on speed and on matching gallons to Sherwin-Williams products, which matters if that's what you're buying.
Why does the coverage assumption change the answer by 14%?
Sherwin-Williams' ~400 sq ft/gal assumption produces about 14% fewer gallons than Lowe's 350 sq ft/gal floor for the same wall — one can in three on a multi-room job. Both are honest numbers from the brands: smoother surfaces and their premium lines genuinely reach 400+, while textured walls, bare drywall and deep color changes drink closer to 350 or less. Plan at 350; enjoy the leftover can when you get 400.
What do neither of the brand calculators tell you?
What the paint job costs. Sherwin-Williams and Lowe's calculators estimate quantity (Lowe's adds labor hours), but neither attaches dollars — no materials total, no pro quote band, no DIY comparison. When you're ready for money, a cost calculator does that line: our interior calculator prices the same room dimensions into gallons, materials and the DIY-vs-pro decision with every formula shown.
Which paint coverage assumption should you trust?
The one printed on your can. Both calculators state their assumptions openly, and both defer to the product data sheet — because a thin builder paint and a thick premium enamel behave differently at the same sheen. The safe planning number across brands is 350 sq ft/gal for one coat on interior walls; treat 400 as the best case, not the plan.
What PaintCalcs doesn't do
- We don't speak for Sherwin-Williams or Lowe's — the quoted lines are from their own calculator pages, checked 2026-10 and (Lowe's) 2026-02, and can change.
- We don't sell their paint or any paint; brand tools are compared on function, not sponsorship.
- Our own calculators price dollars, not gallons-per-brand — for exact product coverage, the can's label wins over any calculator, including ours.