Epoxy Resin Volume Calculator

Epoxy Resin Calculator

If you work with epoxy—whether you make river tables, trays, coasters, jewelry, or 3D castings—one question comes up again and again. How much resin do I actually need? Get it wrong and you waste money, get bubbles, run out mid pour, or end up with a partially cured project. Get it right and you save time, money, and nerves.

This guide explains, in plain English, how epoxy resin calculators work, the math behind them, common pitfalls, and step-by-step examples for rectangular and round (circle) projects. I wrote it like I would explain to a colleague in the workshop: direct, practical, with the key formulas and checks you can use immediately.

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Table of contents

  1. What an epoxy resin calculator does and why it matters
  2. Key concepts you must understand (volume, ml vs cm³, density, mix ratio)
  3. Formulas (rectangle and circle) and unit conversions
  4. Mixing ratios: volume vs weight and why manufacturers often recommend weighing
  5. Example calculations (rectangle and circle) with numbers you can copy
  6. Converter cheat sheet (ml, liters, grams, ounces, m² per mm)
  7. Practical tips: layers, deep pour limits, temperature, bubbles, and waste margin
  8. Best use cases for calculators and available online tools/apps
  9. SEO-friendly FAQs (long tail queries answered)

1 . What an epoxy resin calculator does and why it matters?

A resin calculator converts the physical size of your project into the amount of epoxy (and hardener) you must measure out. A good calculator:

  • Converts dimensions to volume (cubic units).
  • Applies the resin: hardener mix ratio to split the total into Part A and Part B.
  • Converts volume into practical units you use in the shop (milliliters and grams or fluid ounces).
  • Optionally applies density to show mass (useful when you prefer to weigh parts).

Manufacturers and makers use these calculators to avoid waste and to ensure their pours cure correctly. Many brands provide a free calculator on their websites to help their customers plan projects. See examples from TotalBoat and ArtResin.

2 — Key concepts you must understand first

These are the few simple facts that keep most mistakes from happening.

Volume and units

  • Volume is the space you fill. Common units you will use are cubic centimeters (cm³), milliliters (ml), cubic inches, and liters. One cubic centimeter equals one milliliter (1 cm³ = 1 ml). That makes conversions easier.

Density

  • Epoxy density varies by formula. Typical clear epoxies used for art and coating commonly fall around 1.1 to 1.4 g/cm³, depending on additives and whether it is a casting, coating, or modified resin. Use your resin’s technical data sheet for the exact number. If you only have a ballpark, 1.1 g/ml is a reasonable working assumption for many clear epoxies.

Mix ratio

  • The ratio (for example 2:1, 1:1, 3:1, or 100:45) describes resin to hardener. A 2:1 ratio means two parts resin to one part hardener. Ratios can be by volume or by weight. Some systems specify weights (100:45). Always follow the manufacturer. TotalBoat explains why measuring precisely matters and when to prefer weighing.

Pour depth / layer limits

  • Not all epoxies can be poured thick in a single go. “Art” or “tabletop” resins often recommend thin layers (for example 1/8 inch) to avoid heat and bubbles. Deep pour epoxies are formulated to allow thicker single pours (often up to 2 inches depending on the product). Always check the product’s pour depth guidance.

3 — The formulas (short and exact)

Keep these two formulas handy. I’ll show worked examples next.

Rectangle (box / slab / tabletop / tray)
Volume = Length × Width × Height
Use consistent units. If you measure in centimeters, volume will be in cm³ which equals milliliters.

Circle (cylindrical mold, round coaster, round table centerpiece)
Volume = π × r² × h
where r is radius (half the diameter) and h is height (thickness). Again, units must match for the result to be in cm³ or ml.

If you want mm, cm, inches, or meters:

convert first so all three measurements use the same unit.

For practical conversions between cubic inches and US fluid ounces or between liters and cubic centimeters, many online calculators and manufacturer pages show the constants. For example, some resin calculators convert cubic inches to fluid ounces by dividing by about 1.805 (check your calculator’s units).

4 — Mixing ratios: volume vs weight and the simple rule to split parts

If your calculator returns a total volume of epoxy required (A + B combined), split it using the ratio.

General formula if ratio is a:b (resin : hardener):

  • Resin (Part A) = total_volume × a / (a + b)
  • Hardener (Part B) = total_volume × b / (a + b)

Example: total = 900 ml, ratio = 2:1

  • Resin = 900 × 2 / 3 = 600 ml
  • Hardener = 900 × 1 / 3 = 300 ml

Remember: some manufacturers specify the ratio by weight. If you are working with weight, convert volume to mass using density (g/ml) then divide by parts by weight. Many professionals prefer weighing because it removes measurement error from volume tools. TotalBoat has a good guide on measuring by weight vs volume.

5 — Worked examples you can copy

I show two complete examples step by step: one rectangular slab and one round coaster. I use reasonable density and a common ratio so you can see each step. At the end I include the precise amounts for resin and hardener.

Example A — Rectangle slab (river table top coating example)

Project: a tabletop surface 100 cm long × 50 cm wide with a desired epoxy layer thickness of 2 cm (top coat thickness for a thick art piece).

  1. Convert dimensions to consistent units (centimeters are fine).
    L = 100 cm, W = 50 cm, H = 2 cm.
  2. Compute volume (cm³, which equals ml):
    Volume = L × W × H = 100 × 50 × 2 = 10,000 cm³ = 10,000 ml.
  3. Convert to weight if you plan to weigh. Assume density 1.1 g/ml (check your resin TDS; 1.1 is a typical estimate).
    Mass = 10,000 ml × 1.1 g/ml = 11,000 g = 11 kg.
  4. Mix ratio: assume a common 2:1 (resin:hardener) by volume. Apply split formula:
    Resin = total × 2/3 = 10,000 × 0.6666667 ≈ 6,666.67 ml
    Hardener = total × 1/3 = 10,000 × 0.3333333 ≈ 3,333.33 ml
  5. If you prefer to weigh parts (recommended): multiply ml × density to get grams and weigh out those grams.
    Resin mass ≈ 6,666.67 ml × 1.1 g/ml = 7,333.33 g
    Hardener mass ≈ 3,333.33 ml × 1.1 g/ml = 3,666.67 g

Summary (rounded): you need about 10,000 ml (10 liters) total epoxy. With 2:1 volume ratio that is roughly 6.67 L resin and 3.33 L hardener. If you weigh, that equals approximately 7.33 kg resin and 3.67 kg hardener using 1.1 g/ml density.

This example shows why larger pours are hazardous for beginners. Mixing and managing 10 liters is heavy and heat buildup can be a problem. For very thick pours consider a deep pour epoxy and pour in layers. Manufacturer calculators and guidance are useful for this planning.

Example B — Circle coaster or round mold (30 cm diameter, 1 cm thick)

Project: a round mold with diameter 30 cm and height 1 cm.

  1. Radius r = diameter / 2 = 30 / 2 = 15 cm.
  2. Volume = π × r² × h = π × 15² × 1 = π × 225 = 706.858 cm³ (rounded). That equals about 707 ml.
  3. Density estimate (1.1 g/ml): mass ≈ 707 ml × 1.1 = 777.5 g.
  4. Mix ratio 2:1 (resin:hardener) by volume:
    Resin ≈ 707 × 2/3 ≈ 471.3 ml
    Hardener ≈ 707 × 1/3 ≈ 235.7 ml

If you prefer to weigh: resin mass ≈ 471.3 × 1.1 ≈ 518.4 g; hardener mass ≈ 235.7 × 1.1 ≈ 259.1 g.

So for a 30 cm round coaster 1 cm thick expect roughly 707 ml total epoxy; split it per your product’s ratio. This is a small, manageable batch for most tabletop resins.

6 — Quick converters and a cheatsheet

  • 1 cm³ = 1 ml.
  • Typical art epoxy density ≈ 1.1 g/ml. Use manufacturer TDS when available.
  • 1 liter applied over 1 m² = 1 mm thickness. A useful shortcut: if you want 3 mm thickness over 1 m² you will need 3 liters. This assumes density adjustments have been accounted for if you plan to weigh.
  • To split by ratio a:b: Part A = total × a/(a+b), Part B = total × b/(a+b).
  • If your calculator reports volume in cubic inches you can convert to fluid ounces or liters using an online conversion or built-in calculator in most resin brand pages. Many epoxy calculators show direct conversion.

7 — Practical tips: what calculators do not tell you but you must plan for

Always add a safety margin
Plan for waste: spilling, mixing stick residue, and small miscalculations. A 5 to 10 percent extra is common. For complex molds or color mixing where you must tint multiple batches identically, add a larger buffer.

Pour depth and exotherm
Deep pours can overheat during cure. If you pour too much epoxy at once, the exotherm (heat) can cause yellowing, cracking, or even bubbling. Tabletop resins often recommend thin coats (for example 1/8 inch). If you need thick sections, use a deep pour epoxy and follow the product pour guidance. Some deep pour formulas are rated to 2 inches per single pour; others require layering. Always follow the manufacturer.

Mix by weight when possible
Volume measurements are convenient but measuring by weight is usually more accurate. Different temperature and viscosity can slightly change volume measurement accuracy. Many pros weigh resin and hardener with digital scales. TotalBoat and other resin makers recommend this for best results.

Temperature matters
Warmer temperatures reduce viscosity and reduce bubbles, but they also accelerate curing and exotherm. Cooler temperatures extend working time but can cause slow cure. Always mix and pour in the temperature range recommended by the manufacturer.

Explain colorants and additives
Adding pigments or powders changes mass but not volume dramatically. However metallic pigments or heavy fillers can change density and cure behavior. When tinting across batches, pre-mix a slightly oversized master batch or weigh pigments carefully to maintain consistency.

Bubble management
Use a good mixing technique, let the mixed epoxy rest for a minute to allow bubbles to rise, use a heat gun or torch for the surface pass, and pour slowly. If you use thick layers, you may trap more bubbles. Thin multiple layers help bubbles escape.

8 — Online tools, apps and how to pick the right calculator

Many brands publish calculators tailored to their products. These calculators often include unit conversions and recommended pour depths for that brand. Examples include the TotalBoat epoxy calculator and the ArtResin calculator. They are helpful because they can include brand-specific conversion and coverage numbers.

What a good calculator should allow you to do

  • Enter units in mm, cm, inches.
  • Choose shape (rectangle/flat, cylinder, custom).
  • Input pour depth or layer thickness.
  • Pick whether you want the output in ml, liters, ounces, or grams.
  • Specify mix ratio or select the brand formula.
  • Add a waste margin percent.

Apps
If you work on the phone, search for “epoxy resin calculator app.” There are simple calculator apps and brand apps that help on site. If you do a lot of resin work, an app that lets you save multiple templates for common molds saves time.

When to prefer a manufacturer calculator
Use it when volume-to-weight conversions, coverage claims, or the maximum pour depth depend heavily on that product’s chemistry. Brand calculators reflect the product’s density and recommended pour limits.

9 — SEO-friendly FAQs: short answers for common long tail queries

Q: How do I calculate how much epoxy resin I need?

A: Measure the area and desired thickness, compute volume using rectangle or circle formulas, convert volume to the unit you prefer, then split the total volume into resin and hardener using the mix ratio. Use a margin for waste.

Q: What is a resin volume calculator in ml?

A: That is a calculator that outputs the total epoxy volume in milliliters. It is useful because 1 ml = 1 cm³, and a lot of epoxy packaging is in ml or liters.

Q: Should I trust online epoxy calculators?

A: Yes, as a planning tool. But cross-check the density from the product datasheet and follow the manufacturer’s mix and pour instructions. For large pours, test small samples and be conservative.

10 — Common mistakes and how to avoid them

  • Underestimating the safety margin. Always add 5 to 10 percent for small jobs, more for complex molds.
  • Measuring by volume when the manufacturer requires weight. Convert volume to mass if the ratio is given by weight. Weighing is more accurate.
  • Pouring too thick. Know your epoxy’s maximum pour depth and prefer deep pour formulas for thick sections.
  • Mixing large batches at once. Large mixes generate heat. For big jobs, split batches or use slow hardener systems.
  • Ignoring temperature and humidity. These affect cure time and bubble behavior.
  • Not calibrating measuring tools. Ensure your measuring cups, syringes, or scales are zeroed and accurate.

Useful checklist before any pour

  1. Measure your mold/project twice.
  2. Run the volume math and get the total ml.
  3. Check the product density (TDS) if you plan to weigh.
  4. Apply mix ratio formula and calculate Part A and Part B.
  5. Add 5 to 10 percent contingency.
  6. Confirm pour depth limits and select the right epoxy type.
  7. Prepare the workspace temperature according to the technical data sheet.
  8. Mix carefully, stir slowly, and de-gas if necessary.
  9. Pour, torch or heat gently to remove surface bubbles, and monitor cure.

Wrap up and recommended next steps

An epoxy resin calculator is a simple but powerful planning tool. It replaces guesswork with clear numbers, and when combined with knowledge about mix ratios, density, and pour depth it prevents most beginner and intermediate mistakes.

If you want to put the steps into practice:

  • Use the rectangle or circle formulas shown above to compute the volume.
  • Use the mix-split formula to split into A and B.
  • If your epoxy brand has an online calculator, use it for brand-specific conversion and limits. TotalBoat and ArtResin both provide user-friendly calculators.