Epoxy Mix Calculator (2:1 Ratio)
Use this tool to split your total mix into the correct amounts of Part A (resin) and Part B (hardener) at a 2:1 ratio.
If you work with epoxy, a wrong ratio is one of the fastest ways to ruin a project. The good news is that 2:1 resin systems are easy once you follow a repeatable method. This page gives you a practical calculator and a complete guide so you can confidently mix for river tables, coasters, crafts, bar tops, molds, and repairs.
What a 2:1 resin ratio actually means
A 2:1 ratio means you mix:
- 2 parts Part A (resin)
- 1 part Part B (hardener)
That ratio is usually specified by volume, not by weight, unless your manufacturer clearly says otherwise. In practical terms, the total mix is split into 3 equal parts. Two of those parts are resin, one part is hardener.
Quick formula for a 2:1 epoxy mix
If your desired total mixed amount is T:
- Part A = T × 2/3
- Part B = T × 1/3
Example with 300 ml total:
- Part A = 300 × 2/3 = 200 ml
- Part B = 300 × 1/3 = 100 ml
If you add a 10% waste buffer, calculate using 330 ml instead of 300 ml.
How to use this 2 1 resin calculator
Method 1: You already know your total volume
- Enter your required total mixed volume.
- Add a waste margin (recommended).
- Click Calculate 2:1 Mix.
Method 2: You know dimensions, not volume
- Enter length, width, and depth in centimeters.
- Click Estimate Total from Dimensions.
- The calculator fills your total in ml (because 1 cm³ = 1 ml).
- Then calculate the 2:1 split.
Mixing by volume vs mixing by weight
Most hobby epoxies are ratioed by volume. However, many makers use digital scales for precision. If you mix by weight, you must account for different densities of Part A and Part B.
This calculator includes optional density inputs so you can see approximate gram targets as well. Always verify density values in your product technical data sheet for best accuracy.
Common mistakes that cause sticky or soft epoxy
- Wrong ratio: Even small errors can leave uncured spots.
- Poor scraping: Unmixed resin on cup walls causes failure.
- Short mix time: Mix slowly but thoroughly for 2–3 minutes.
- Cold environment: Low temperatures increase viscosity and slow cure.
- Switching brands or systems: Do not combine unrelated resin/hardener sets.
Practical tips for cleaner, more reliable pours
- Pre-measure both parts before adding pigments.
- Use two-cup mixing: mix in one cup, transfer, mix again.
- Warm bottles gently (if manufacturer allows) to reduce bubbles.
- Work in smaller batches for deep pours to manage heat.
- Record your batch size, room temp, and cure result for future jobs.
2:1 resin examples
Example 1: Coaster set
You need 120 ml total and want 10% extra:
- Adjusted total: 132 ml
- Part A: 88 ml
- Part B: 44 ml
Example 2: Thin flood coat
Panel dimensions: 60 cm × 40 cm × 0.2 cm
- Volume = 4,800 cm³? No—careful with decimals.
- Correct volume = 60 × 40 × 0.2 = 480 cm³ = 480 ml
- Add 10% waste = 528 ml total mix
- Part A = 352 ml, Part B = 176 ml
FAQ
Can I eyeball a 2:1 epoxy mix?
Not recommended. Even minor ratio drift can lead to tacky finishes, cloudy cure, or weak mechanical strength.
Should I always add a waste margin?
Yes. Most projects benefit from 5–15% extra material to cover cup residue, drips, uneven surfaces, and slight underestimates.
Does 2:1 always mean volume?
Usually yes, but not always. Check your product label and technical data sheet. Follow manufacturer instructions over any generic rule.
Final takeaway
A reliable 2:1 mix is simple: calculate accurately, measure carefully, and mix thoroughly. Use the calculator above before every pour, especially when changing project size. Consistency is what turns epoxy from frustrating to professional.