Stone calculator
Stone Coat Epoxy Calculator
Epoxy is sold by the kit and spread by the mil. Enter the surface, edge drop and coat plan to see gallons, kits and total cost — including the waste that runs off the edges.
Your project
Only the edges epoxy can run over. Edges against a wall do not count.
Crews typically order 5-10% extra to cover compaction, spillage and uneven subgrade.
Epoxy needed
22.11
gallons
- Top surface
- 480 sq ft
- Edge surface
- 2.5 sq ft
- Total coated area
- 482.5 sq ft
- Film thickness
- 70 mil total
- Kits to buy
- 15 × 1.5 gal
- Epoxy cost
- $1,800
- Base coat paint
- 5 quarts
- Pot life at 75°F
- About 30-40 minutes per batch
Coverage assumes 1 gallon spreads roughly 12 sq ft at 1/8 inch. Warm epoxy self-levels thinner and cold epoxy sits thicker, so mix in batches you can spread inside the pot life rather than pouring the whole kit at once.
The shareable link reopens this calculator with your exact inputs.
How epoxy coverage is calculated
Epoxy coverage is a film-thickness problem, not an area problem. One gallon spread at 1 mil covers about 1,604 square feet, so at a 60 mil flood coat that same gallon covers roughly 26 square feet — and at a full 1/8 inch (125 mil) it covers about 12 square feet.
A typical kitchen counter takes a 10 mil seal coat to lock the base colour and stop outgassing, then a 60-70 mil flood coat for the glass finish. That is close to 1.5 gallons for 40 square feet of top plus its edges.
Edges are where the epoxy goes
Epoxy runs off the edge and drips on the floor. Add the edge area — linear feet times the drop in inches, divided by 12 — to your top area, then allow 10-15% waste on top of that. On a 1.5 inch bullnose edge running 20 feet, that is another 2.5 square feet of coated surface plus the run-off you never recover.
Tape a drip line under the edge and set the counter on blocks over plastic. Do not try to reuse the drips: partly cured epoxy will not level.
Mixing and temperature
Mix by volume at the ratio on the kit (usually 1:1), for a full three minutes, scraping the sides and bottom, then pour into a second bucket and mix again. Unmixed resin at the wall of the bucket is the single most common cause of soft spots.
Work between 70°F and 80°F. Below 65°F the epoxy stays thick, traps bubbles and cures cloudy; above 85°F pot life drops under 20 minutes and the batch can exotherm in the bucket.
Epoxy coverage per gallon by film thickness
| Film thickness | Coverage per gallon | Typical use |
|---|---|---|
| 10 mil | 160 sq ft | Seal / base coat |
| 30 mil | 53 sq ft | Light refresh coat |
| 60 mil | 27 sq ft | Standard flood coat |
| 125 mil (1/8") | 12.8 sq ft | Deep pour / bar top |
| 250 mil (1/4") | 6.4 sq ft | River table pour |
Kits needed for common projects
| Project | Area | Seal + flood coat | Kits (1.5 gal) |
|---|---|---|---|
| Bathroom vanity | 12 sq ft | 0.6 gal | 1 |
| Small kitchen | 30 sq ft | 1.4 gal | 1 |
| Standard kitchen | 45 sq ft | 2.1 gal | 2 |
| Kitchen with island | 70 sq ft | 3.2 gal | 3 |
| Bar top (8 ft) | 16 sq ft | 0.8 gal | 1 |
Frequently asked questions
+How much epoxy do I need for a kitchen countertop?
About 1.5 to 2 gallons for a typical 40-50 sq ft kitchen — that is a 10 mil seal coat plus a 60-70 mil flood coat, with edges and 10% waste included.
+How many square feet does a gallon of countertop epoxy cover?
Roughly 12 sq ft at 1/8 inch, 27 sq ft at a 60 mil flood coat, and 160 sq ft as a thin 10 mil seal coat.
+Do I need a seal coat before the flood coat?
Yes on any porous base — wood, plywood, concrete or laminate with exposed edges. The seal coat stops air escaping through the substrate and blowing bubbles into your finish coat.
+How thick should a stone coat epoxy pour be?
1/8 inch total is the standard for countertops. Deeper single pours risk overheating; if you want more depth, build it in 1/8 inch layers 4-8 hours apart.
+How long before I can use the counter?
Dust-free in about 8 hours, light use at 24-36 hours, full chemical and heat cure at 7 days. Do not set hot pans on it even after full cure.