How Many Bags of Self-Leveling Underlayment Do You Need?
Enter your floor area, average pour depth, and the coverage printed on your bag. You'll see how many bags to buy, with waste and whole-bag rounding included.
Last updated: August 27, 2026
Current estimate
100 sq ft · 0.25 in · 10% waste
5bags
Use an average from several low spots, not the deepest dip across the whole room.
Underlayment Order Summary
100 sq ft · 0.25 in average depth · 24 sq ft/bag at 0.25 in · 10% waste
Worked examples
Small bathroom
100 sq ft · 1/4 in average depth · 24 sq ft/bag at 1/4 in · 10% waste
That fifth bag is the extra full bag the store actually sells you after the 10% allowance.
Open living area
250 sq ft · 1/8 in average depth · 40 sq ft/bag at 1/8 in · 10% waste
Use the coverage printed on your bag when it differs from this example.
Uneven hallway
180 sq ft · 1/4 in average depth · 20 sq ft/bag at 1/4 in · 10% waste
If the hallway has separate deep and shallow zones, calculate each zone and add the bag counts.
Self-leveling coverage by depth
Coverage falls as the pour gets deeper. This table uses your current coverage and reference-depth inputs and excludes waste.
| Pour depth | Coverage per bag | Bags for 100 sq ft |
|---|---|---|
| 1/8" | 48 sq ft | 3 |
| 1/4" | 24 sq ft | 5 |
| 1/2" | 12 sq ft | 9 |
| 1" | 6 sq ft | 17 |
How to choose your depth
Measure the floor at several points and use the average thickness you expect to pour. A single deepest low spot should not be multiplied across the whole room.
When the room has clearly different areas, run each zone separately and add the resulting whole-bag counts. Always check the product's maximum single-pour depth before ordering.
Use the coverage printed on the exact product you plan to buy. Manufacturer coverage changes with product, substrate, application method, and thickness.