About the Self-Leveling Compound Calculator
This self-leveling compound calculator estimates how many bags of self-leveling underlayment (SLU, often called self-leveling concrete or floor leveler) you need to flatten a floor before tile, vinyl plank or hardwood. Enter the room length and width, the average depth you expect to pour, and the yield printed on the bag, and it returns the volume, the number of bags, the coverage of each bag at that depth and the material cost.
Floors are rarely out by the same amount everywhere, so the key input is the average depth: map the low spots with a long straightedge or laser, estimate the depth at several points and average them. Most products can be poured from a featheredge up to about 1 to 1-1/2 inches in one lift; check the product’s maximum thickness and whether it needs aggregate for deep fills.
A typical 50 lb bag yields about 0.45–0.55 cubic feet, which covers roughly 50 sq ft at 1/8 inch or 25 sq ft at 1/4 inch. Because self-leveler must be poured continuously and cannot be topped up later without a new primer coat, buy at least 10% extra so you never run short mid-pour.
With the default inputs, the bags needed is 7. Change any value above to recalculate instantly.
How to use the self-leveling compound calculator
- 1Measure the room length and width in feet.
- 2Find the low spots with a straightedge and estimate the average depth to fill.
- 3Enter the yield per bag from the product label.
- 4Add at least 10% extra so the pour is never interrupted.
- 5Buy the bags shown, plus primer for the full floor area.
Formula and method
The floor area (length × width in feet) multiplied by the average depth converted from inches to feet gives the volume of leveler in cubic feet. The extra allowance covers material lost in buckets and hoses and the uncertainty in your average depth.
Dividing by the yield per bag and rounding up gives the bags to buy. Coverage per bag is the bag yield spread at your depth: a 0.5 cu ft bag covers 0.5 ÷ (0.25 ÷ 12) = 24 sq ft at 1/4 in. Yields vary by brand and by how much water you add, so always use the figure printed on the bag.
- L, W
- Room length and width (ft)
- D
- Average pour depth (in)
- yield
- Mixed volume per bag (cu ft)
Worked examples
12 × 12 ft room at 1/4 in average
A 144 sq ft floor at 1/4 in needs 3 cubic feet of leveler, or 3.3 with 10% extra. Each 0.5 cu ft bag covers 24 sq ft at that depth, so 6.6 bags rounds up to 7, about $280.
20 × 15 ft basement at 1/8 in
At 1/8 in a 300 sq ft floor needs 3.125 cubic feet, 3.44 with extra. Each bag covers 48 sq ft at this thin depth, so seven bags do the job.
Deep 1/2 in fill in a 10 × 8 ft bathroom
80 sq ft at 1/2 in is 3.33 cubic feet. With a 0.45 cu ft yield each bag covers just 10.8 sq ft, so 7.4 bags rounds up to 8 — and buying a ninth bag as a spare is sensible.
Frequently asked questions
How much area does a 50 lb bag of self-leveler cover?+
Most 50 lb bags yield about 0.5 cubic feet, which covers roughly 50 sq ft at 1/8 in, 25 sq ft at 1/4 in and about 12 sq ft at 1/2 in. Check the coverage chart on your product, since yields vary by brand.
How thick can self-leveling concrete be poured?+
Standard self-leveling underlayments are typically rated from a featheredge up to about 1 to 1-1/2 in in one pour. Deeper fills usually require a deep-pour product, added pea gravel, or multiple lifts with primer between them.
Do I need primer before self-leveling compound?+
Almost all manufacturers require a primer on concrete or wood subfloors. It seals the surface so water is not pulled out of the mix too quickly, improves bond and prevents pinholes. Wood subfloors may also need metal lath.
How do I find the average depth to pour?+
Lay a long straightedge or use a laser level across the floor and measure the gap at a grid of points. Average the readings, giving more weight to large low areas; areas already at level count as zero.
How long before I can walk on self-leveler?+
Many products can take light foot traffic in about 2–4 hours and accept tile within roughly a day, but moisture-sensitive floor coverings may need longer. Follow the drying times on the bag for your thickness and temperature.