Self-Leveling Calculator: Bags of Floor Leveler by Depth and Product

1. Pick the self-leveler. Its bag size, yield, depth limits and mix water fill in from the data sheet.
2. Enter the floor area. For a flat floor, enter one depth. For a slope, switch to sloped and enter the thin-end and thick-end depths.
3. Add your own waste allowance. Read the bags, then check the verdict band against the pour limits.

A self-leveling calculator estimates how many bags of floor leveler a job needs. It turns a floor area and a pour depth into a volume, then divides by the volume one bag makes.

The depth is the hard part. Real floors are rarely flat, so the layer is thin in one spot and thick in another. A single average thickness hides that. This tool takes a thin-end and a thick-end depth and averages them, and it warns if the thick end passes the single-pour limit.

This page is an independent tool. It is not affiliated with or endorsed by ARDEX, Custom Building Products, MAPEI or LATICRETE. For the tile and floor covering that follows, see the tile calculator.

One bag makes a fixed volume of leveler. Spread thin, it covers more area. Spread thick, it covers less. The product of area and depth stays constant.

1. Average depth. Add the thin-end and thick-end depths and divide by two. For a flat floor the average is the single depth.
2. Yield. This is the square feet times inches that one bag covers. A bag that covers 24 sq ft at 1/4 in has a yield of 24 x 0.25 = 6.
3. Bags. Area times average depth divided by the yield, times one plus your allowance, rounded up.
4. Check. The thick end must stay under the single-pour maximum. The thin end must stay over the minimum.

I read these figures on 2026-10-03 in the documents under Sources. The yield is my own arithmetic from their coverage rows. The rows follow area times depth closely: the Mapei, LATICRETE and Custom tables give yields of 6.00 to 6.75, 6.00 to 6.12 and 5.70 to 6.00. The top of the Mapei range comes from its 3/4 in row, where 9 sq ft is a rounded figure.

Take a 400 sq ft room. A survey shows the floor needs 1/8 in of leveler at the thin end and 1/2 in at the thick end. The 10 percent allowance is only an example.

1. Average depth: (0.125 + 0.5) / 2 = 0.3125 in.
2. Volume: 400 x 0.3125 / 12 = 10.42 cu ft.
3. Mapei Ultraplan Easy (yield 6): 400 x 0.3125 / 6 = 20.83 bags. With 10 percent: 22.92 bags, so buy 23 bags of 50 lb.
4. ARDEX K 15 (yield 7.5): 400 x 0.3125 / 7.5 = 16.67. With 10 percent: 18.33 bags, so buy 19 bags of 55 lb.
5. NXT Level Plus (yield 6 to 6.125): 22.45 to 22.92 bags, so buy 23 bags of 55 lb at the conservative yield.
6. LevelQuik RS (yield 5.75 to 6): 22.92 to 23.91 bags, so buy 24 bags of 50 lb at the conservative yield.

The bag count is not the weight. The K 15 job is 19 x 55 = 1045 lb. The Ultraplan Easy job is 23 x 50 = 1150 lb. Compare products by weight as well.

This table shows square feet per bag at common depths, computed from each yield. It uses the low yield, so it is the safe figure for ordering.

These are my arithmetic. Where a data sheet prints the same depth, the figure matches within the published range. The K 15 sheet prints only the 1/4 in figure, so the other K 15 rows follow from it.

Five things move the answer. The calculator handles the first three.

Depth and Slope

Bags scale with depth. Doubling the average depth doubles the bags. A deeper low spot raises the average more than most people expect.

Product Yield

Yield per bag differs by product and bag size. Compare by weight and yield, not by bag count.

Floor Area

Measure the area you will actually pour. Include alcoves and closets.

Substrate and Primer

ARDEX notes that coverage depends on surface profile, density and porosity. Porous concrete takes more material and needs primer. The calculator does not count primer.

Pour Limits

Each product has a single-pour maximum. A thicker fill needs a second lift or an aggregate extension, which changes the quantity.

The four sheets give different pour limits and mix ratios.

The calculator checks your thin and thick depths against these limits. For a deeper fill, read the data sheet. This page does not size multi-lift or aggregate-extended pours.

Before Laying Tile or Plank

Size the leveler, then plan the covering with the tile flooring calculator.

Sloped Floors

Use two depths from a floor survey instead of one guess.

Comparing Products

Switch the product and keep the floor. The weight to buy shows which suits your budget.

Budgeting the Work

Add the bags to your plan with the renovation budget guide.

1. Using One Thickness for a Sloped Floor

The deep end drives the quantity. Enter both depths.

2. Counting Bags Instead of Weight

A 55 lb bag and a 50 lb bag are different units.

3. Pouring Past the Single-pour Limit

Each product has a maximum. The verdict band flags it.

4. Skipping the Allowance

Low spots and spills use extra. See the material waste guide.

5. Forgetting Primer

The data sheets call for primer on most substrates. Buy it separately.

6. Confusing Area with Volume

Compare with a plain slab estimate in the slab volume guide only for volume, not for bag yields.

The yields come from the manufacturers coverage rows, so the bag math is exact for the depths you enter. Real floors vary more than the yield does.

The K 15 data sheet states its coverage depends on surface profile, density and porosity. MAPEI states real coverage varies with substrate and application method.

At 1/4 in with no waste, about 20.8 bags of Ultraplan Easy, 16.7 of ARDEX K 15, 20.8 of NXT Level Plus and 21.7 of LevelQuik RS. Add your own allowance.

It depends on depth. A 50 lb bag of Ultraplan Easy covers 24 sq ft at 1/4 in and 6 sq ft at 1 in. A 55 lb bag of ARDEX K 15 covers 30 sq ft at 1/4 in.

Average the thin-end and thick-end depths, then use that average. The result is exact for a flat slope. Switch the tool to sloped and enter both depths.

It depends on the product. K 15 goes up to 1 1/2 in neat, LevelQuik RS to 1.5 in, Ultraplan Easy and NXT Level Plus to 2 in in one lift, per their data sheets.

ARDEX asks for 1/8 in over the highest point. MAPEI lists 1/16 in and LATICRETE lists 1/8 in over concrete. LevelQuik RS lists featheredge.

No. The data sheets call for primer on most substrates and give separate rates. Buy primer on top of the bag count, using each primer data sheet.

The sheets list 7 qt for a 55 lb bag of K 15, 5.25 to 5.75 qt for LevelQuik RS, 5.75 to 6 qt for Ultraplan Easy and 5.0 to 5.5 qt for NXT Level Plus. The tool totals it for you.

Products differ in bag weight and in the volume each bag makes. K 15 yields 7.5 sq ft inches per 55 lb bag. Ultraplan Easy yields 6 per 50 lb bag.

Yes. Pick Custom yield, then type the bag size and the square feet times inches that one bag covers, plus the depth limits from your own data sheet.

No. The calculation runs in your browser and nothing is sent to our servers. Anything you choose to Save stays in this browser only.

• ARDEX K 15 technical data sheet: packaging, coverage, thickness and water ratio (ARDEX, content updated 2026-04, read 2026-10-03).
• LevelQuik RS Rapid Setting Self-Leveling Underlayment, TDS-108: coverage per 50 lb bag (Custom Building Products, published 1/18/2024, read 2026-10-03).
• Ultraplan Easy data sheet: application range and approximate coverage per 50 lb (MAPEI, document dated 2024-08-02, read 2026-10-03).
• NXT Level Plus data sheet DS-505-0726: approximate coverage and pour thickness (LATICRETE, read 2026-10-03).