Epoxy Calculator
Estimate epoxy resin volume for countertops, tabletops, bar tops, river tables, floor coatings, garage floors, art pours, seal coats, flood coats, and casting projects. Calculate total epoxy needed, resin and hardener amounts, recommended kit size, coverage, and project cost.
Calculate Epoxy Needed
Your Epoxy Estimate
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Formula used:
Practical recommendation:
Quick Formula Box
Surface area = length × width × number of similar areas − deductions
Volume in cubic feet = surface area × epoxy thickness in feet
Epoxy gallons = cubic feet × 7.48052
Epoxy with waste = epoxy gallons × waste factor
Resin amount = total epoxy × resin parts ÷ total mix parts
Hardener amount = total epoxy × hardener parts ÷ total mix parts
Total cost = rounded kit quantity × kit price + tax + optional labor cost
Epoxy Coverage Reference Table
| Epoxy Project | Typical Thickness | Approx. Coverage Per Gallon | Common Epoxy Type | Planning Tip |
|---|---|---|---|---|
| Seal coat on wood | 1/32 in | About 513 sq ft/gal | Tabletop or coating epoxy | Used to seal porous surfaces before a flood coat. |
| Thin coating | 1/16 in | About 257 sq ft/gal | Coating epoxy | Useful for light protective coats and smooth surfaces. |
| Tabletop flood coat | 1/8 in | About 128 sq ft/gal | Tabletop / bar top epoxy | Common for counters, bar tops, desks, and tabletops. |
| Heavy flood coat | 1/4 in | About 64 sq ft/gal | Self-leveling coating epoxy | Requires careful edge control and suitable product depth. |
| Garage floor coating | Varies by system | Often 100–250 sq ft/gal | Floor coating epoxy | Manufacturer spread rate matters more than depth calculation. |
| River table channel | 1/2 in to several inches | Depth-based volume | Deep pour casting epoxy | Use deep pour epoxy and pour within the product’s maximum depth. |
| Art resin pour | 1/16 to 1/8 in | 128–257 sq ft/gal | Art resin | Add extra for pigments, runoff, cups, and leveling. |
| Bar top coating | 1/8 in | About 128 sq ft/gal | Bar top epoxy | Seal coat first if wood is porous or has cracks. |
| Concrete countertop coating | 1/16 to 1/8 in | 128–257 sq ft/gal | Countertop epoxy | Prime or seal concrete when recommended by the product. |
| Deep casting | 1 in+ | Depth-based volume | Deep pour epoxy | Never exceed the manufacturer’s maximum pour depth. |
How to Use the Epoxy Calculator
Epoxy Calculator Guide
An epoxy calculator helps estimate how much epoxy resin you need before starting a coating, casting, countertop, tabletop, river table, floor, or art project. Epoxy is usually sold as a kit that includes resin and hardener, and the correct amount depends on surface area, thickness, waste, project shape, and the manufacturer’s coverage guidance.
This calculator uses the standard volume method for epoxy: surface area multiplied by thickness. It then converts cubic feet to gallons and adds a waste allowance. For most flat projects, this method gives a practical planning estimate. For floors where the product label gives a spread rate, use the label as the final authority.
What This Epoxy Calculator Does
The tool estimates total epoxy gallons, resin volume, hardener volume, recommended kit size, net project area, cubic volume, material cost, optional labor cost, tax, and total estimated cost. It can be used as a resin calculator, epoxy resin calculator, tabletop epoxy calculator, countertop epoxy calculator, river table epoxy calculator, garage floor epoxy calculator, bar top epoxy calculator, and art resin estimator.
The default workflow requires only length, width, thickness, and price. More detailed settings are kept inside Advanced Options so first-time users can calculate quickly without being overwhelmed by technical inputs.
Why Epoxy Estimating Matters
Running short during an epoxy pour can cause seams, uneven flow, color differences, incomplete coverage, and rushed mixing. Buying too much can be expensive because epoxy has a shelf life and often cannot be returned after opening. A good estimate helps you order enough resin and hardener, prepare the right number of mixing containers, and plan the working time before the pour begins.
Epoxy projects also need margin. Some material remains in buckets, on spreaders, in notches, around edges, inside cracks, and on the floor or drop cloth. Porous wood, live edges, knot holes, uneven concrete, pigments, mica powder, embedded objects, and runoff can all increase material use.
Epoxy Formula Explained
The basic epoxy formula is:
Epoxy gallons = length × width × thickness in feet × 7.48052
Because thickness is usually measured in inches, the calculator converts inches to feet by dividing by 12. One cubic foot contains about 7.48052 gallons. After the base volume is calculated, the tool adds waste and divides the total epoxy into resin and hardener according to the selected mix ratio.
For a 1:1 epoxy kit, half the total volume is resin and half is hardener. For a 2:1 kit, two-thirds is resin and one-third is hardener. Always follow the manufacturer’s ratio by volume or by weight exactly. Do not assume all epoxy products use the same ratio.
Seal Coat vs Flood Coat
A seal coat is a thin first coat used to seal porous surfaces such as wood, concrete, or live-edge slabs. It helps reduce bubbles and prevents the flood coat from soaking unevenly into the surface. Seal coats are usually much thinner than flood coats.
A flood coat is a thicker self-leveling coat used to create the glossy finish on tabletops, bar tops, countertops, desks, and art panels. A common planning thickness is around 1/8 inch, but product instructions may vary. Deep pours and river tables require casting epoxy, not ordinary tabletop epoxy.
Deep Pour and River Table Projects
River tables and casting projects need special attention because epoxy depth creates heat during curing. Too much depth with the wrong epoxy can overheat, yellow, crack, smoke, bubble, or cure poorly. Deep pour epoxy is formulated for thicker pours and longer working time, while tabletop epoxy is usually intended for shallow coating thicknesses.
If you are filling a river channel, void, mold, knot, or cavity, measure the actual void volume when possible. For irregular channels, estimate average width and average depth, or divide the channel into sections. Add extra for live-edge voids, bark pockets, end grain absorption, leaks, and test pours.
Epoxy Floors and Garage Floors
For garage floors and concrete floors, coverage is often specified by the coating manufacturer in square feet per gallon rather than by a fixed depth. Concrete porosity, moisture, surface preparation, primer, flakes, topcoat, and coating system all affect the real quantity. Use this calculator for volume planning, but check the product’s stated spread rate before buying.
Floor coating systems may include primer, base coat, color flakes, grout coat, and clear topcoat. Each layer has a different coverage rate. A single epoxy gallon estimate may not represent a complete floor system.
Practical Applications
DIY and Home Projects
Woodworking and Professional Uses
Common Epoxy Estimating Mistakes
The most common mistake is forgetting thickness. Epoxy volume increases quickly as depth increases. A project that needs 1 gallon at 1/8 inch may need 8 gallons at 1 inch. Another mistake is using tabletop epoxy for deep casting. Ordinary coating epoxy is usually not designed for thick pours.
People also underestimate waste. Edges, cracks, seams, live edges, porous wood, mixing containers, pigments, and runoff all use material. For small art pours, the waste percentage can be higher because small batches lose more material in cups and spreaders.
Expert Recommendations
Read the epoxy product instructions before mixing. Check mix ratio, working time, temperature range, humidity limits, maximum pour depth, recoat window, curing time, and surface preparation requirements. Measure accurately, mix thoroughly, scrape the sides and bottom of the container, and avoid whipping excessive air into the resin.
Prepare everything before pouring. Epoxy work is time-sensitive. Have gloves, cups, spreaders, torch or heat gun if appropriate, tape, drop cloths, pigments, level surface, edge dams, and cleanup supplies ready. For deep pours, seal cracks and test for leaks before mixing a large batch.
Conclusion
This epoxy calculator gives a practical estimate for epoxy gallons, resin and hardener amounts, kit quantity, coverage, and total project cost. It is useful for tabletops, countertops, floors, river tables, art resin, bar tops, molds, and casting projects. Final epoxy needs depend on product type, thickness, mix ratio, surface porosity, project shape, waste, temperature, and manufacturer instructions.