How the Bag Count Is Figured
Mapei publishes coverage per 50 lb bag at set thicknesses. Those figures follow one rule: a bag covers about 6 square feet at 1 inch thick, or 0.5 cubic feet.
1
Square Feet × Inches
Multiply the floor area by the average thickness in inches. A 400 square foot floor at 1/4 inch gives 100 square-foot-inches.
2
Divide by 6
One bag supplies 6 square-foot-inches. Dividing 100 by 6 gives 16.67 bags of raw material for the pour.
3
Add Overage
Multiply by 1 plus your overage. At 10%, 16.67 becomes 18.33 bags to cover spills, low spots, and mixer loss.
4
Round Up
You cannot buy part of a bag, so 18.33 rounds up to 19 bags. Primer and mixing water follow from the area and bag count.
Coverage per Bag at Each Thickness
Use this lookup to check your result. It lists Mapei's published coverage for a 50 lb bag and the value this calculator uses.
| Thickness |
Mapei Data Sheet Coverage |
Calculator Value (6 ÷ thickness) |
Bags per 100 ft² |
| 1/8 in | Not listed | 48 ft² | 2.1 |
| 1/4 in | 24 ft² | 24 ft² | 4.2 |
| 1/2 in | 12 ft² | 12 ft² | 8.3 |
| 3/4 in | 9 ft² | 8 ft² | 12.5 |
| 1 in | 6 ft² | 6 ft² | 16.7 |
| 1-1/2 in | 4 ft² (Ultraplan 1 Plus only) | 4 ft² | 25.0 |
| 2 in | 3 ft² (Ultraplan Easy only) | 3 ft² | 33.3 |
Coverage is from Mapei technical data sheets and is for estimating only. The 3/4 in data sheet value (9 ft²) is higher than the 8 ft² the other rows imply, so this calculator uses the 6 ÷ thickness rule and orders slightly more at 3/4 in.
For thin leveling over a worn slab, compare this with the concrete overlay calculator. Overlays are placed differently, so the two tools do not share coverage rates.
Ultraplan and Novoplan Compared
All three products are cement-based, come in 50 lb bags, and are for interior use only. They differ in thickness limits, water, and wait times.
| Item |
Ultraplan 1 Plus |
Ultraplan Easy |
Novoplan Easy Plus |
| Single-lift range | 1/16 to 1-1/2 in | 1/16 to 2 in | 1/8 to 1 in |
| Water per 50 lb bag | 5.75 to 6 qt | 5.75 to 6 qt | 5 to 5.28 qt |
| Flow time | Up to 15 min | Up to 15 min | Up to 15 min |
| Ready for tile at 1 in | 3 hours | 3 hours | 24 hours |
| Moisture-sensitive flooring at 1 in | 16 to 24 hours | 16 to 24 hours | 2 to 3 days |
| Cured density | 122 lb/ft³ | Not listed | 128 lb/ft³ |
Source: MAPEI technical data sheets for each product. Shorter drying times are possible with thinner pours.
Primers are chosen by substrate. Mapei lists Primer L for porous concrete and gypsum, and Primer T for porous and nonporous concrete, plywood, tile, and resilient floors.
What Self-Leveling Underlayment Does
Self-leveling underlayment is a flowable cement mix poured over a prepared floor to fill low spots and create a flat surface for tile, vinyl, or carpet.
It levels, but it does not repair a failing slab. A cracked or delaminating floor needs fixing first, so read about how to fix cracked concrete and concrete delamination before you pour.
Cement-based underlayments also do not block moisture. The data sheets say moisture mitigation must be done before the underlayment goes down if the flooring needs protection from slab humidity.
If the surface needs a decorative or wear finish instead of a flat base, see the concrete resurfacing guide. Cured self-leveler must be covered by a finished floor and is not a wear surface.
For a thicker bonded topping, the concrete bonding adhesive guide covers a different bond method. Check the data sheet before mixing any product with a self-leveler, because Mapei says not to.
Jobsite Scenarios
These sample calculations show how flooring contractors might size a pour. They are illustrations, not documented projects.
🏢 Condo Renovation, Flat Slab
Product: Ultraplan 1 Plus
Area: 400 sq ft at 1/4 in
Overage: 10%, Primer T, one application
Raw bags: 400 × 0.25 ÷ 6 = 16.67
With overage: 18.33, so buy 19 bags
Water: 19 × 5.75 to 6 qt = 109 to 114 qt
Primer T: 400 ÷ 200 to 400 = 1 to 2 gal
Buy primer for the low end of the coverage range, then keep a quart for patching edges.
🏬 Retail Space, Sloped Slab
Product: Ultraplan Easy
Area: 1,200 sq ft
Thickness: 1/8 in thin, 3/4 in thick
Average: (0.125 + 0.75) ÷ 2 = 0.4375 in
Raw bags: 1,200 × 0.4375 ÷ 6 = 87.5
With 10%: 96.25, so buy 97 bags
Both ends fit the 1/16 to 2 in single-lift range. A straight-line slope averages well, but a floor with a deep dip needs patching first.
🛁 Bathroom Over Plywood
Product: Novoplan Easy Plus
Area: 150 sq ft at 1/2 in
Overage: 10%, Primer T
Raw bags: 150 × 0.5 ÷ 6 = 12.5
With 10%: 13.75, so buy 14 bags
Added weight: 0.5 ÷ 12 × 128 = 5.3 lb per sq ft
5.3 pounds per square foot is extra dead load on a wood floor. Ask the engineer of record whether the framing can carry it.
Jobsite Conditions and Wait Times
🌡️
Temperature
The data sheets call for 50°F to 85°F during application and for 3 days before and after. Do not let the fresh mix freeze.
⏱️
Flow Time
Mixed material flows for up to 15 minutes. Plan batches so a crew can pour, rake, and smooth each one without stopping.
🧱
Concrete Age
Concrete should be at least 28 days old and free of hydrostatic pressure. Deflection of the supporting floor must not exceed L/360.
🚶
Walking and Loads
Avoid walking on Ultraplan 1 Plus or Novoplan Easy Plus for 2 to 3 hours. Keep rolling loads off for at least 3 days.
Our guide on when you can walk on concrete covers general slab timing, but self-leveler follows the product data sheet.
To compare finished-floor budgets, run the flooring cost calculator or the concrete overlay cost calculator.
Sources and Method
- MAPEI levelers and toppings product calculator (5% to 10% overage guidance): mapei.com
- MAPEI Ultraplan 1 Plus technical data sheet (coverage, 5.75 to 6 qt water, 1/16 to 1-1/2 in single lift, 122 lb/ft³ density, drying times): Ultraplan 1 Plus TDS
- MAPEI Ultraplan Easy technical data sheet (coverage to 2 in, 1/16 to 2 in single lift, 5.75 to 6 qt water): Ultraplan Easy TDS
- MAPEI Novoplan Easy Plus technical data sheet (coverage, 5 to 5.28 qt water, 1/8 to 1 in single lift, 128 lb/ft³ density, drying times): Novoplan Easy Plus TDS
- MAPEI self-leveling underlayments and primers chart (Primer T 200 to 400 sq ft per gal, Primer L 600 to 800 sq ft per gal): PlaniLevel and primers chart
- MAPEI Primer T technical data sheet (50 to 100 sq ft per quart, drying windows): Primer T TDS
- MAPEI Primer L technical data sheet (coverage when diluted 3:1): Primer L TDS
Coverage uses the rule of 6 square feet per bag at 1 inch, which matches the data sheet values at 1/4, 1/2, 1, 1-1/2, and 2 inches. Added weight equals thickness in feet times cured density.
Last reviewed: October 2026. Reviewed by site author.
⚠️ Disclaimer
This calculator provides estimates for planning purposes. For permitted structural work, foundations, multi-story construction, retaining walls over 4 feet, and commercial projects, calculations must be verified by a licensed structural engineer per IBC 2024 §1604. ConcreteCalculate.com is not liable for structural decisions made from these estimates.
ConcreteCalculate.com is not affiliated with MAPEI. Product names are trademarks of their owners. Always follow the current MAPEI technical data sheet and warranty terms for your project.
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