Estimate bags of self-leveling underlayment by dividing the floor area by one bag’s coverage at the measured average depth, adding a waste allowance, and rounding up. With ARDEX K 15, for example, a 55 lb bag covers about 30 sq ft at 1/4 in, so 600 sq ft at an average 3/8 in needs about 30 bags before waste, provided the selected substrate and primer system permits that thickness. MeasureSet, the PDF takeoff app from Automata Labs, measures and exports the areas; you apply the product’s coverage math in Excel or a calculator.
This guide explains the math, the one number a plan cannot give you, and a quick way to get the area right.
Measure floor-plan areas on your PC and export them for a product-specific bag estimate.
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What does a bag of self-leveler cover?
Coverage depends on the product, so always read the technical data sheet for the one you are buying. As a worked reference, the ARDEX K 15 technical data sheet (dated 2 April 2026) gives these figures for its 55 lb bag:
| Item | ARDEX K 15 figure |
|---|---|
| Coverage | About 30 sq ft per bag at 1/4 in (2.8 m2 at 6 mm), depending on surface profile, density and porosity |
| Mixing water | 7 quarts (6.6 L) per bag |
| Average minimum depth | 1/4 in |
| Maximum over ARDEX VB 100, P 82 or P 4 primers | 1/4 in |
| Maximum in the TDS’s other permitted applications | 1 1/2 in neat; up to 5 in with aggregate as specified |
| Minimum over the high point | 1/8 in, which typically gives at least a 1/4 in average |
| Walkable | 2 to 3 hours under the stated conditions |
| Ready for flooring | About 16 hours, or 6 hours for moisture-insensitive tile, under the stated conditions |
The substrate and primer system determine which thickness limits apply. This is quantity-estimating guidance, not an installation specification. Follow the current manufacturer instructions for preparation, priming, mixing and drying; another product can have different coverage and limits.
How do you calculate the number of bags?
For an approximate neat-material estimate, coverage scales inversely with depth. A bag that covers 30 sq ft at 1/4 in covers about 20 sq ft at 3/8 in and about 15 sq ft at 1/2 in. Those deeper examples apply only where the selected system permits them. Do not plan below K 15’s 1/4 in average minimum or beyond the applicable maximum at any point.
- Area. Measure the floor area to be poured, in square feet.
- Average depth. Estimate it from an on-site survey, in inches, and check the minimum and maximum depths separately.
- Coverage at that depth. Coverage at 1/4 in multiplied by 0.25, divided by your average depth.
- Bags. Area divided by coverage at your depth.
- Waste. Add an explicit allowance for mixing loss and site conditions. The 10 percent used below is illustrative, not an ARDEX-required factor.
- Round up. You cannot buy part of a bag.
In one line: multiply area by average depth, divide by (reference coverage multiplied by reference depth), multiply by (1 plus the waste fraction), then round up to whole bags. Use consistent area and depth units. Aggregate-extended fills need the manufacturer’s separate guidance rather than this neat-material scaling alone.
Can you show a worked example?
Suppose an on-site survey of a 600 sq ft kitchen and dining area indicates an average 3/8 in pour. This example assumes an approved substrate and primer system that permits that depth, with all high and low points within its limits; it is not suitable for the primer combinations capped at 1/4 in above.
- Coverage at 3/8 in: 30 multiplied by 0.25, divided by 0.375, which is about 20 sq ft per bag.
- Bags before waste: 600 divided by 20, which is 30 bags.
- With an illustrative 10 percent margin: 33 bags.
- If all 33 bags are mixed at 7 US quarts each: 231 quarts, or 57.75 US gallons.
The TDS specifies two-bag manual mixes, so rounding the illustrative order to 34 bags can accommodate that batching choice. Water is still measured per bag actually mixed; do not add water to stretch coverage. These are estimated quantities, not a quote, a site survey or an installation plan.
Why can’t the floor plan tell you the depth?
A floor plan gives you the area. It does not tell you how far out of level or flat the existing slab or subfloor is. That has to be measured on site:
- Survey the floor. Shoot a grid of points with a laser level, or check with a long straightedge, and note the high and low spots.
- Find the high point. The pour has to cover it by at least the product’s minimum. For K 15, the data sheet says a minimum of 1/8 in over the high point typically gives a 1/4 in average.
- Estimate the average. Average your grid readings relative to the planned finished surface. Low corners and dips raise the average quickly.
- Split the area if needed. If one room needs 1/4 in and another needs 3/4 in, calculate them separately rather than averaging the whole floor.
This is why bag counts from a plan alone often run short. The area is easy; the depth is where the surprises are.
Group areas by planned pour depth and export the quantities for a bag estimate.
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How do you take the area off a PDF floor plan?
You can scale it off with a ruler and a calculator, or measure it on screen.
With MeasureSet:
- Open and calibrate the plan PDF. Click both ends of a known dimension and enter its length, then check a second dimension. A standard scale is another option for a full-size drawing. See how to set scale on a PDF drawing.
- Measure each pour area. The room tool can find a closed room; inspect its boundary. Open-plan spaces or interrupted outlines may need a point-by-point area trace. Points snap to other marks’ corners, not automatically to the drawing’s walls.
- Deduct what is not poured. Mark excluded areas such as a fixed island base or a shower pan as deductions, following the actual installation scope.
- Name labels for the product and depth. For example, keep Kitchen at 3/8 in separate from another permitted depth. These are labels you assign, not room names automatically extracted from the plan.
- Export and apply coverage math. Export the Marks and Totals tables to Excel or CSV, then divide each net area by coverage at its surveyed average depth. Add your chosen waste allowance and round up. MeasureSet can carry label depth and waste for quantities, but this workflow does not assume an automatic bag-coverage calculator. Apply waste only once.
- Keep a marked-up PDF. Export the measured sheets and totals so the scope behind the estimate can be reviewed.
Your plan PDFs are never written over, and there is no account or upload. MeasureSet is a takeoff ruler, not an estimating suite or a substitute for the on-site depth survey.
What else should you order with the self-leveler?
The bag count is not the whole order. Check the product’s data sheet and installation instructions for:
- Primer. Self-levelers commonly call for a primer over the substrate, and the data sheet names which one. Primer coverage is listed separately.
- Edge and perimeter materials. Foam edging or dams to contain the pour.
- Aggregate. If any area is deeper than the neat maximum, the data sheet will say what aggregate to add and in what ratio.
- Mixing equipment. A drill and paddle, measured water containers and enough buckets for a continuous pour.
Frequently asked questions
How much does one bag of self-leveler cover?
It depends on the product and depth. ARDEX K 15’s data sheet gives about 30 sq ft per 55 lb bag at 1/4 in. Double the depth and coverage roughly halves.
Is it better to buy extra bags?
A small margin is sensible, because running out mid pour is a real problem with a product that sets quickly. Check the retailer’s return policy for unopened bags.
Can I use the same math for a different brand?
Yes. Replace the coverage figure with the one on that product’s data sheet.
Does MeasureSet know the floor depth?
No. Depth comes from a site survey. MeasureSet measures and exports plan quantities. Use the surveyed depth and the product’s coverage in your spreadsheet or calculator; a label depth for volume is not an automatic bag-coverage calculation.
Can I estimate flooring from the same takeoff?
Yes. Add another label for the flooring. See how many boxes of flooring to order.
Try MeasureSet
MeasureSet is a one-time purchase with a free trial in the Microsoft Store; the listing shows the current price and system requirements. Open your next floor plan, measure the rooms that need leveling and set up one label per depth. More detail is on the MeasureSet product page, and our guide on thinset bags from a floor plan covers the tile setting step.
Export the measured floor areas, then apply the manufacturer’s coverage to your order estimate.
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