Self-Leveling Compound Calculator
Your floor
Measure with a long straightedge; use the average gap, not the deepest.
Bags of leveler (50 lb)
7
- Depth
- 1/4 in
- Coverage per bag
- ~23 sq ft
- Volume
- ~3.1 cu ft
- Primer
- 1 gal
Mix and pour continuously — SLU has about a 10-minute working time once mixed.
Tools the pros use for this job
Self-Leveling Compound
Top-rated SLU bags — check the max pour depth on the label.
Mixing Paddle
Edward Tools Paint and Mud Mixer for Drill - Mixes 1 to 3 Gallons - 15 3/4" Length - 5/16" Hex Shaft - Zinc Plated Steel - Reinforced Weld - Non Slip Hex Head - Easy Clean - Paint Mixer Attachment
Check price on AmazonSLU has a 10-minute pot life. You need a drill paddle, not a stick.
Uncoupling Membrane
The layer on top that keeps slab movement away from your tile.
Paid links — we may earn a commission at no extra cost to you.
How this calculator works
A 50 lb bag covers roughly 45 sq ft at 1/8 inch — and coverage halves every time depth doubles. The depth to use is the average depth across the low spots, not the deepest point: find the low spots with a long straightedge, estimate the average gap, and round up.
Primer matters: unprimed concrete sucks the water out of SLU and it cracks. One gallon of primer covers about 350 sq ft. Pour the whole floor in one session — SLU self-welds only while wet, and a cold joint becomes a crack line under tile.
Frequently asked questions
How thick can I pour self-leveling compound?
Standard SLU pours from a featheredge to about 1/2 inch per lift; extended formulas with aggregate go to 1–2 inches. Check the bag — exceeding the rated depth causes cracking.
Can I use SLU over a wood subfloor?
Yes, with the right product: it must be rated for plywood, the floor must be rigid (screw down squeaks first), and you use metal lath or the manufacturer's primer system. Never pour standard SLU straight onto bare plywood.
How long before I can tile over it?
Most SLUs accept tile in 4–24 hours (check the bag). Moisture-sensitive tile like natural stone may need longer — test with a moisture meter on big pours.
Related calculators
- Thinset & Mortar CalculatorBags of thinset by trowel notch size and coverage.
- Floor Tile CalculatorTiles and boxes for any floor, by room dimensions and tile size.
- Large Format Tile Calculator24-inch-plus tiles: counts, leveling clips, and handling extras.
- Backer Board CalculatorCement board sheets, screws, and tape for floors and walls.
Guides worth reading next
- Leveling a Floor for Tile: Flat vs Level, and How to Fix BothWhy tile needs flat (not level), the straightedge test, self-leveling compound basics, primers, and depth math that decides your bag count.
- Large-Format Tile: Is Your Floor Flat Enough?The 1/8-in-in-10-ft rule, why 15-inch tile changed the standards, how to test your slab with a straightedge, and what fixing it costs.
- How to Measure a Room for Tile (Step by Step)Measure any room for floor or wall tile: handle closets and alcoves, convert inches to decimals, subtract fixtures, and add the right waste percentage.