Calculator
Example data table
| Project | Area | Coverage | Coats | Waste | Porosity | Recommended | Buy (1 gal) |
|---|---|---|---|---|---|---|---|
| Garage floor | 480 sq ft | 200 sq ft/gal | 2 | 10% | 1.00 | 5.280 gal | 6 containers |
| Patio | 300 sq ft | 250 sq ft/gal | 1 | 8% | 1.10 | 1.426 gal | 2 containers |
| Driveway | 1,200 sq ft | 175 sq ft/gal | 2 | 12% | 1.20 | 18.432 gal | 19 containers |
| Warehouse aisle | 150 m² | 5.5 m²/L | 2 | 10% | 1.00 | 14.980 gal | 15 containers |
Examples are illustrative. Always verify the manufacturer’s stated coverage for your product and surface.
Formula used
This calculator estimates sealer quantity using a coverage-based approach, then applies coats, surface porosity, and a waste allowance.
- Base gallons = (Area ÷ Coverage) × Coats × PorosityFactor
- Gallons with waste = BaseGallons × (1 + Waste% ÷ 100)
- Containers = Round( GallonsWithWaste ÷ ContainerSize )
- Total purchase = Containers × ContainerSize
How to use this calculator
- Select your unit system and input mode.
- Enter slab dimensions or total area for the surface.
- Type the coverage rate from your sealer label.
- Choose the number of coats you will apply.
- Adjust porosity for rough or absorbent concrete.
- Add a waste factor to protect against shortfalls.
- Set container size and optional pricing for budgeting.
- Press Calculate, then download CSV or PDF if needed.
Quick guidance for better estimates
Professional field guide
1) Typical coverage ranges
Clear acrylic, silane/siloxane, and polyurethane sealers commonly list coverage between 150–300 sq ft per gallon per coat on smooth concrete. Broom finishes, exposed aggregate, or aged slabs often fall toward the lower end because the surface has more texture and open pores.
2) Why coat count changes totals
Each coat is effectively a separate application with its own film build or penetration requirement. Two coats can improve uniformity and reduce lap marks, but material demand scales nearly linearly with coat count. This calculator multiplies the base volume by the number of coats to reflect that job reality.
3) Porosity factor as a jobsite control
Porosity is a practical adjustment knob when substrate absorption is uncertain. New slabs, lightweight mixes, or aggressive surface prep can increase uptake. Use 1.10–1.30 for porous concrete, and closer to 0.90 for dense, steel-troweled finishes where penetration is limited and coverage is higher.
4) Waste factor and production loss
Even experienced crews lose material to tray residue, roller saturation, sprayer lines, overlaps, and edge detailing. A 5–12% waste factor is typical for rollers on moderate texture. Sprayer work outdoors may need 10–20% depending on wind, masking, and overspray recovery practices.
5) Container sizing for procurement
Buying in 1, 2.5, or 5 gallon containers affects both cost and scheduling. Larger containers can reduce packaging cost but may raise leftover volume if the project is small. This tool converts the recommended quantity into whole containers using a rounding rule that fits your purchasing policy.
6) Budgeting with consistent pricing
For bids and change orders, use a single pricing basis: per container, per gallon, or per liter. If you enter price per container, the estimate follows the container count exactly. If you enter unit pricing, cost tracks the purchase quantity after rounding, which is usually closer to invoiced totals.
7) Documentation and closeout value
Exporting CSV or PDF helps verify material planning, supports submittal packages, and improves closeout documentation. Include product name, batch numbers, and application notes in the project notes field so the report becomes a quick reference for warranty discussions or maintenance planning.
8) Practical validation before full application
Before committing to a full order, run a small test section (for example 100–200 sq ft), measure actual consumption, and back-calculate the effective coverage for your substrate. Update the coverage rate and porosity factor here to lock in a more defensible material quantity.
FAQs
Start with the midpoint of the manufacturer’s range, then adjust after a small test area. Rough or absorbent surfaces usually need the lower-end coverage value.
Rounding up is safer for production schedules and avoids stoppages. Nearest rounding can reduce leftovers, but it risks running short if absorption is higher than expected.
Use 1.00 for typical cured concrete, 1.10–1.30 for porous or heavily profiled surfaces, and 0.90–0.95 for dense, steel-troweled slabs with minimal absorption.
Many products and suppliers list packaging in different unit systems. Showing both helps compare data sheets, plan purchases, and communicate requirements across mixed-unit teams.
Yes. Penetrating sealers can vary with porosity, while film-forming products depend on target thickness. Always follow the product data sheet and adjust coverage inputs accordingly.
For indoor spraying with good control, 10–15% is common. Outdoors, wind and overspray can push waste to 15–20% or more depending on site conditions.
You can, but expect different absorption and application loss. Stamped and textured surfaces typically need lower coverage and a higher waste factor due to recesses and detailing.
Seal smarter, buy accurately, and finish with confidence always.