How much epoxy resin do you need? Calculate the combined volume of resin and hardener for a tabletop, flat mould or decorative panel. Enter your dimensions and wet thickness, add a reserve, and optionally work out how many complete kits to buy.
How to use the epoxy resin calculator
- Choose a rectangle, circle or known area. Measure the actual surface or the inside of the mould. Enter how many identical pieces you are making.
- Enter the total wet thickness. Choose its unit separately from the length unit. If applicable, subtract the area of full-depth cutouts from each piece.
- Add separately estimated extra litres for the whole project and choose a reserve percentage.
- For a shopping estimate, enter the combined mixed volume and price of one complete kit. Click Calculate epoxy.
The result shows litres, millilitres, US liquid gallons and a calculation breakdown. Use decimals such as 0.125 for one eighth of an inch. A point or comma is accepted, but fractions and thousands separators are not. Changing units converts existing measurements. Recalculate after editing.
How much epoxy do I need for a flat surface?
For a uniform layer, mixed volume equals net area multiplied by wet thickness. A useful metric shortcut is: 1 m² at 1 mm thick requires 1 litre of mixture before any extra allowance.
Rectangle area = length × width. Circle area = π × (diameter ÷ 2)². Subtract the cutout area from one piece before multiplying by the number of identical pieces.
Geometric volume in litres = net area per piece in m² × total wet thickness in mm × number of pieces.
Total to allow = (geometric volume + additional project litres) × (1 + reserve percentage ÷ 100).
The cutout field applies to each piece. The additional litres field applies to the whole project once. For pieces with different dimensions or depths, calculate each separately and add their volumes. Do not apply the same reserve twice when combining results.
Example: a rectangular tabletop
A top measuring 120 × 60 cm has an area of 0.72 m². At 3 mm total wet thickness, the geometric volume is 0.72 × 3 = 2.16 litres. With no extra volume and a 10% reserve, allow 2.376 litres of combined resin and hardener.
If one complete kit provides 1.5 litres, you need two kits. That gives 3 litres, or 0.624 litres above the estimate including reserve. At an illustrative price of €45 per kit, the kit cost is €90. Load example fills in these values. The thickness and price are arithmetic examples, not product recommendations.
Example: six round coasters
For six straight-sided circular moulds with an inside diameter of 10 cm and a fill depth of 5 mm, the geometric volume is about 235.619 mL. Adding 10% gives about 259.181 mL. A complete kit yielding 300 mL would cover that calculated quantity. Check the actual mould shape and your product's casting limits before using these dimensions.
Example: a cutout in a panel
Suppose the same 120 × 60 cm panel has a 0.10 m² opening receiving no epoxy. Its net area is 0.72 − 0.10 = 0.62 m². At 3 mm, it needs 1.86 litres before reserve. For two identical panels, the opening is subtracted from both and the geometric total becomes 3.72 litres. Any extra project litres are then added once.
Which volume should I enter for an epoxy kit?
Enter the usable combined mixture from one complete resin-and-hardener kit. If a product's stated mixed yield is 1.5 litres, enter 1.5 L. Do not enter the resin bottle volume alone. Confirm the yield with the supplier when the label is unclear.
The calculator divides the required volume by the mixed yield per kit and rounds up to whole kits. It assumes you are buying matching, complete kits. It does not combine leftovers of separate components, compare different kit sizes or find the cheapest pack combination.
A kit sold by weight cannot be entered directly into a volume field. Litres measure volume and kilograms measure mass. Use the manufacturer's mixed yield, or its specified mixed density to make the appropriate conversion. There is no universal litres-to-kilograms conversion for epoxy.
Does the result include the hardener?
Yes. It is the total mixed volume. The tool does not tell you how much Part A or Part B to dispense. Follow the exact ratio and measuring method on your product instructions. A ratio by weight is not automatically the same as a ratio by volume.
Does 10% extra cover every project?
No. The starting reserve is editable. Cups, tools, runoff and uneven surfaces can use more material than the ideal flat volume. A separate seal coat or porous surface can also change the quantity. Enter a separately estimated amount in additional project litres where you can, then choose an allowance suited to the remaining uncertainty.
For example, if you have already estimated 0.20 litres for an additional operation, enter 0.20 in the extra field. With a 2.16 litre geometric volume and 10% reserve, the result becomes (2.16 + 0.20) × 1.10 = 2.596 litres. Do not enter the same allowance again elsewhere.
Can I calculate a river table or an irregular mould?
A simple rectangular channel of constant width and depth fits rectangle mode. A constant-depth irregular outline can use an accurately measured area. A curved, tapered or uneven cavity needs a separate volume estimate. The overall table dimensions would count the wood as if it were resin, so do not use them for the river cavity.
A full-depth insert can be represented by its cutout area. An object that only occupies part of the depth cannot. This tool does not calculate the displacement of complex objects, rounded mould walls, domed surfaces or shrinkage.
Can I mix the whole result in one batch?
The result is a purchase quantity, not a batch instruction. Curing epoxy generates heat. Check the product's maximum batch size, layer depth, working temperature, pot life and recoat instructions. Adding several layer thicknesses here does not make that combined depth suitable for one pour.
Follow the product safety data sheet for gloves, eye protection and ventilation. This calculator does not select a resin system or verify that it suits your substrate, depth or intended use.
Are these US or UK gallons?
All gallon results and kit inputs use US liquid gallons. One US liquid gallon is 3.785411784 litres. An Imperial gallon is a different unit and is not offered here. Use litres if your product label does not make the gallon type clear.
Check your product and plan the rest of the project
TotalBoat's epoxy coverage guide explains flat and round volume calculations and why real projects need allowances. Its TableTop technical instructions illustrate product-specific mixing and application limits. Always use the current instructions for the product you actually buy.
For other updates in the room, try our paint calculator, furniture wrap calculator or picture frame and mat calculator. The generated photo illustrates a finished project and does not show a recommended mixing setup or a measured example.
