How Much Epoxy Do I Need? (Coverage Calculator Guide)
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Ordering too little epoxy halfway through a job is every DIYer's nightmare, and ordering way too much wastes money. This guide shows you how to work out exactly how much epoxy you need for your garage floor, with simple maths and the numbers that actually matter.
Step 1 - Measure your floor area
Measure the length and width of your garage in metres and multiply them together to get your area in square metres (m²).
Area = length (m) x width (m)
Typical Australian garages come out around:
- Single garage: roughly 18-21 m² (e.g. 6m x 3.2m)
- Double garage: roughly 36-40 m² (e.g. 6m x 6m)
Step 2 - Know your coverage rate
Every coating has a coverage rate - how many square metres a litre (or a kit) will cover at the recommended thickness. This is the single most important number, and it is always on the product page or data sheet. Coverage depends on:
- The coat: primer, colour coat and clear top coat each have their own rate.
- Surface porosity: rough or porous concrete drinks more product, especially on the primer coat.
- Number of coats: most floors get a primer, one or two colour coats, and a clear top coat.
Step 3 - Do the calculation
For each coat:
Product needed = floor area (m²) ÷ coverage rate (m² per unit)
For example, if your garage is 20 m² and a kit covers 20 m² per coat, you need one kit per coat. Add up the primer, colour and top coats to get your total.
Step 4 - Add a safety margin
Always add around 10% to your total. You will lose a little product to the roller, the tray, edges, and uneven patches of slab. Running 10% over is cheap insurance against running out mid-coat - which is a real problem with epoxy because each batch you mix is on a clock.
A worked example
Say you have a single garage of 20 m² and you want primer + one colour coat + one clear top coat, where each kit covers about 20 m²:
- Primer: 20 ÷ 20 = 1 unit
- Colour coat: 1 unit
- Clear top coat: 1 unit
- Add 10% margin across the job
The simplest way to avoid the maths entirely is to buy a complete kit sized for your garage, where the primer, colour and top coat quantities are already matched to the area.
Don't forget prep products
Coverage matters for prep too - degreaser and concrete etch are sold by area as well, so measure once and order everything for your m² in one go.
Want the easy route? Our garage floor epoxy kits are sized for single and double garages with matched primer, colour and top coat quantities - or get in touch with your measurements and we will help you size it.