Short answer: measure the concrete area, check the coverage rate for the exact sealer, then multiply the area by the number of coats. Do not assume every 20L concrete sealer covers the same area—surface profile, porosity and the product itself can change the result considerably.
The safest calculation is:
Litres required = total area in m² × number of coats ÷ coverage rate in m²/L
When a Technical Data Sheet (TDS) gives a coverage range, calculate using the lower figure before buying. That allows for the heavier usage expected on a rougher or more porous surface. Always follow the current TDS for the exact product rather than relying on a generic online calculator.
Step 1: Measure the concrete area
Break an irregular driveway, shed floor, patio or path into simple shapes, calculate each section and add them together.
- Rectangle or square: length × width
- Triangle: base × height ÷ 2
- Circle: 3.14 × radius × radius
For example, a driveway measuring 10 metres long and 6 metres wide has an area of:
10m × 6m = 60m²
If there is a second section measuring 4m × 3m, add another 12m², giving a total sealing area of 72m².
Step 2: Find the product’s coverage rate
Coverage is normally stated as square metres per litre and is a theoretical guide. The figures below come from the current technical sheets for two products sold by Gippsland Concreting Supplies.
| Sealer | TDS coverage | Theoretical coverage from 20L for one coat |
|---|---|---|
| Auseal Curite Same Day / Exposed AG Sealer 20L | 5–7m²/L, depending on surface profile and porosity | Approximately 100–140m² |
| Dulux Avista Waterbased Concrete Sealer 20L | 5–10m²/L theoretical spread rate | Approximately 100–200m² |
These are not interchangeable promises. A rough exposed-aggregate surface will generally consume more material than a smooth, dense surface. Application method, concrete porosity and how evenly the product is spread also affect practical coverage.
Step 3: Allow for every coat
If the same product requires two coats, multiply the area by two before dividing by the coverage rate.
Example: 80m² driveway, two coats, sealer rated at 5–7m²/L
- At 7m²/L: 80 × 2 ÷ 7 = approximately 22.9L
- At 5m²/L: 80 × 2 ÷ 5 = 32L
For planning purposes, the conservative calculation is 32L. One 20L pail would not be enough for two coats across that 80m² area at the lower coverage rate.
If the first and second coats use different products, calculate them separately. For example, the Auseal Same Day Primer Sealer TDS recommends an additional coat of Auseal Clear Sealer for optimum performance. Calculate the primer using the Same Day Sealer TDS, then calculate the Clear Sealer using its own current TDS. Do not simply double one product’s coverage figure.
Quick example: 60m² concrete area
| Coverage rate | One coat | Two coats of the same product |
|---|---|---|
| 5m²/L | 12L | 24L |
| 7m²/L | Approximately 8.6L | Approximately 17.2L |
| 10m²/L | 6L | 12L |
This table shows why the product choice matters. The same 60m² surface could theoretically use between 6L and 12L for one coat before practical site conditions are considered.
Why actual coverage can be lower
The published spread rate is a guide under suitable conditions. More sealer may be used when:
- the concrete is porous, weathered or heavily profiled;
- the surface is exposed aggregate rather than smooth concrete;
- the first coat absorbs quickly;
- the roller nap is too heavy for the surface or coating;
- the sealer is applied unevenly;
- material remains in the pail, tray, roller or equipment; or
- the area includes edges, joints, steps or detailed sections.
A small practical allowance can prevent running out midway through a coat, particularly on a large or irregular job. However, buying extra does not mean applying extra. Heavy coats and pooling can cause whitening, bubbling, slow curing and an uneven finish.
Choosing the right sealer before calculating
Do not choose quantity before choosing the product. The substrate, age of the concrete, location and finish all matter.
- Auseal Curite Same Day / Exposed AG Sealer: formulated for fresh green concrete that is sufficiently hard to walk on, with 5–7m²/L coverage stated in the TDS.
- Dulux Avista Waterbased Concrete Sealer: a water-based clear coating with a theoretical spread rate of 5–10m²/L.
- Auseal Clear Sealer: a general-purpose acrylic sealer for suitable dry concrete surfaces.
- Auseal Curite Colour Sealer 20L EC25: a coloured acrylic sealer available in multiple colours.
- Dulux Avista Exposed Aggregate Concrete Sealer 20L: designed for suitable exposed-aggregate concrete.
- Dulux Avista General Purpose Concrete Sealer Semi Gloss 20L: a solvent-based clear coating for suitable exterior concrete.
Coverage rates are product-specific. Check the latest TDS linked on the selected product page before ordering or applying.
Application tools
The right applicator helps produce a thin, even coat and makes the stated coverage easier to achieve. Match the roller nap and equipment to the chosen sealer and concrete profile.
- Lambswool Roller Cover 230mm – LW03L
- 230mm 12mm Nap Roller Covers – 5 Pack
- 230mm Heavy Duty Roller Frame – PR4
- Heavy Duty Adjustable Roller Frame – PR30 460mm
- Twist Lock Extension Pole
- Chemical-Resistant Measuring Jug
- Masterfinish Industrial Concrete Sprayer 13.2L – 308S
Only use a sprayer where the exact sealer TDS permits that application method and the sprayer’s seals, materials and nozzle are compatible. An airless spray specification does not automatically approve a conventional pressure sprayer.
Do not forget slip resistance
Sealing can reduce slip resistance, particularly on wet, smooth or sloping surfaces. Where the selected sealer system permits it, consider Dulux Avista Slip Reducing Additive Powder and follow its current TDS for dosage and coat placement. Do not guess the additive quantity from the total litres alone.
Before you order
- Measure every section and calculate the total square metres.
- Select the correct sealer for the concrete and intended finish.
- Read the latest TDS and confirm its coverage rate and required coats.
- Calculate each product separately if the system uses a primer and topcoat.
- Use the lower end of a coverage range for conservative planning.
- Allow for the actual surface profile and a reasonable amount of application loss.
- Do not overapply unused material simply because it was purchased.
Need help calculating your job?
Send Gippsland Concreting Supplies the length and width of each concrete section, the surface type, the age of the concrete and the sealer you are considering. We can help calculate the approximate quantity and match it with suitable rollers, frames and application equipment.
Important: Calculations in this guide are estimates only. Always follow the latest manufacturer TDS and SDS for the exact product. Coverage can vary with surface profile, porosity, preparation, weather and application technique.
