Understanding your result
The headline is the bags of self-leveler, with the area, the average depth, the weight and the primer beneath it. The table shows the area to level, the average depth, what one bag covers at that depth, the bags, the weight and the primer.
Average depth is the key input. If you entered the deepest and shallowest points, the average is half their sum, which is right for a floor that slopes evenly and approximate for one with a single hollow. One bag covers is the bag’s printed coverage at 1/8 in, scaled to your depth: twice the depth, half the coverage. Bags are the area divided by that coverage, plus a mixing allowance.
The share of the floor input is where most money is saved. A floor with one low corner does not need a full pour; enter the fraction of the area that is low and the bag count falls accordingly. The weight is there because self-leveler is heavy and is mixed bag by bag against a short working time, usually 10 to 20 minutes, so a big pour needs helpers. For deeper build-ups over about an inch, the floor screed calculator is the better tool; for wood subfloors, the subfloor plywood calculator; and to see whether the leveled floor now meets the next room, the floor height calculator.
How we calculate this
Coverage scales inversely with depth because a bag makes a fixed volume of leveler. The default of 47 sq ft per 50 lb bag at 1/8 in is from Custom Building Products’ coverage chart for LevelQuik RS (46 to 48 sq ft at 1/8 in, 23 to 24 at 1/4 in); other products are close but not identical, so enter yours. The guide to self-leveling compound explains how to map a floor and pour it, and the large-format tile guide covers the flatness that big tiles demand, which is usually why a floor is being leveled.
The assumptions behind the numbers
| Assumption | Default | Where it comes from |
|---|---|---|
| Coverage | 47 sq ft per 50 lb bag at 1/8 in (4.4 m² per 22.7 kg at 3 mm) | Custom Building Products LevelQuik RS coverage chart: 46 to 48 sq ft at 1/8 in |
| Depth | 1/4 in (6 mm) average | A typical correction under tile or plank |
| Allowance | 10% | Mixing losses and material left in the bucket |
| Primer | about 300 sq ft per gallon, diluted | Typical leveler primer data sheets |
| Neat depth | 1/8 to about 1 in | Typical self-leveler limits; extend or pour in lifts beyond |
| Working time | 10 to 20 minutes | Typical rapid-setting levelers |
Assumptions last reviewed October 8, 2026.
The calculator does not measure the floor for you or know where the low spots are, and the average-of-two-points method is only fair on an evenly sloping floor; a dished floor needs a grid of measurements. It does not count the dams, foam strip or lath, or judge whether a slab is dry enough; a slab with moisture coming through needs a test and possibly a barrier first. It also cannot fix a floor that bounces, which needs stiffening before any leveler.
Two worked examples
A full 1/4 in pour over 200 sq ft
- Coverage at 1/4 in: 47 × (0.125 ÷ 0.25) = 23.5 sq ft per bag
- Bags: 200 ÷ 23.5 × 1.10 = 9.4, rounded up to 10 bags
- Weight 500 lb; primer 0.73 gallon
Ten bags is a two-person pour at least: one mixing, one spreading, with every bag mixed and poured inside the working time. It is the reason a full pour is planned like a concrete job.
Part of a 14 × 11 ft kitchen, 3/4 in down to 1/8 in
40% of the floor is low; the deepest point is 3/4 in and the shallowest 1/8 in.
- Area to level: 154 × 0.40 = 62 sq ft
- Average depth: (0.75 + 0.125) ÷ 2 = 0.44 in; coverage 47 × 0.125 ÷ 0.44 = 13.4 sq ft per bag
- Bags: 62 ÷ 13.4 × 1.10 = 5.05, rounded up to 6 bags
Pouring only the low part takes six bags; ordering for 3/4 in over the whole kitchen would have been about 21. Feathering the edge up to the high part of the floor needs a product rated for a feather edge, or a separate patch.
Where to find your inputs
Area and share. Measure the room, then mark the low areas with a straightedge and estimate what fraction of the floor they cover.
Depth. Measure gaps under a straightedge or a laser at many points; average them, or enter the extremes.
Coverage. On the bag or the data sheet, at 1/8 in (3 mm). If the bag gives coverage at 1/4 in, double it.
Bag size. On the bag; 50 lb is standard in the US.
Common mistakes
- Ordering for the deepest point over the whole floor. Average the depth and pour only where it is low.
- Extra water for an easier pour. It weakens the surface and makes it dusty. Use the water on the bag.
- Skipping primer. The slab draws the water out and the leveler fails to bond.
- No dams at doorways. Leveler flows wherever the floor lets it.
- Pouring past the working time. Mix bag by bag and keep the pour moving.
- Leveling a bouncy floor. Stiffen it first; leveler cracks on a moving floor.
Questions people ask
- How much self-leveling compound do I need?
- A 50 lb bag of a typical leveler covers about 47 sq ft at 1/8 inch and about 23.5 sq ft at 1/4 inch. A 200 sq ft floor at an average 1/4 inch needs 8.5 bags before waste and 10 with a 10% mixing allowance.
- How do I find the average depth?
- Lay a long straightedge or a laser line across the floor and measure the gaps at a grid of points, then average them. If you only know the deepest and shallowest points and the floor slopes evenly, half their sum is a fair average; the calculator does that for you.
- How thick can self-leveler be poured?
- Most self-levelers pour from 1/8 inch to about 1 inch neat, and to 2 inches or more when extended with clean pea gravel or poured in lifts, depending on the product. Check the minimum and maximum depth on the bag.
- Do I need primer before self-leveler?
- Yes, almost always. Primer seals a porous slab so it does not suck the water out of the leveler, and helps it bond. A gallon of diluted primer covers roughly 300 sq ft; follow the maker's dilution for your substrate.
- Can I use self-leveler on a wood subfloor?
- Many products allow it over a sound, stiff wood subfloor with a primer and metal lath or a reinforcing mesh fastened down, and a minimum depth that is usually more than over concrete. Check that the leveler is rated for wood.
- How long before I can lay flooring on self-leveler?
- Many rapid-setting levelers take foot traffic in 2 to 4 hours and tile in a day; moisture-sensitive floors such as wood and vinyl often need 1 to 3 days or more, depending on depth and conditions. The product data sheet gives the times.