Resin Mold Volume & Mix Split Calculator
Eliminate curing failures and under-fills. Input your mold shape, choose your brand preset, and calculate the exact grams of Part A (Resin) and Part B (Hardener) required.
Resin Volume Estimator
Scale from 1 prototype to full production run
MEASUREMENT OUTPUTS
Recipe & Batch Summary
Studio Batch of 1 piece of rectangle mold (10cm x 10cm x 2cm) using Generic Epoxy: • Per Single Unit: 121.0g Resin (A) + 121.0g Hardener (B) [Total: 242.0g]. • Total Studio Run (1 Units): 121.0g Resin (A) + 121.0g Hardener (B) [Total Mass: 242.0g]. • Mix Ratio: 1:1 | Safety Margin: 10%.
MakerRatio • Studio Workshop Batch Sheet
https://makerratio.com • Precision Craft Formula Record
Date: _______________
Batch #: ____________
Project: Generic Epoxy (rectangle x 1)
Category: Epoxy Resin
Dimensions: 10 x 10 x 2 cm (x1)
Mix Ratio: 1:1 | Batch: 1 unit(s)
Specific Gravity: 1.1 g/ml
Safety Spill Margin: 10%
Batch Mix Breakdown (By Exact Weight)
Workshop Safety & Quality Protocol:
[ ] Ambient room temp 70°F–78°F (21°C–25°C) & mold leveled.
[ ] Protective nitrile gloves on & workspace ventilation active.
[ ] Mix thoroughly scraping sides and bottom for 3 full minutes.
[ ] Verify pot life and demold window per manufacturer TDS.
Curing Schedule Log:
Pour Time: ___________
Gel / Tack-Free: ______
Demold Time: ________
Recommended Materials & Tools for this Project
Puduo 1:1 Crystal Clear Tabletop Epoxy
Formula: 1:1 mix ratio. High-gloss self-leveling surface coating for countertops, tumblers, and shallow mold castings.
Heavy-Duty Silicone Coaster Molds Pack
Specification: Flexible, tear-resistant platinum silicone molds (circle and hexagon) with thick sidewalls to prevent bowing.
Transparency Notice: As an Amazon Associate, MakerRatio earns from qualifying purchases at zero extra cost to you. Product recommendations are selected based on verified Manufacturer Technical Data Sheets (TDS). Always consult chemical safety data before pouring.
How to Calculate Epoxy Resin Volume and Weight Ratios
Casting epoxy resin requires exact chemical proportions. Unlike simple water or solvent mixtures, epoxy is a thermosetting polymer. When Part A (resin) and Part B (hardener) mix, they undergo a covalent cross-linking chemical reaction. Incorrect ratios leave unreacted monomer molecules suspended in the matrix, leading to sticky, rubbery casts, bubbles, or cloudy layers.
To calculate the exact weight of resin needed, you must follow three fundamental physical stages: volume determination, density scaling, and ratio division.
1. Geometric Volume Calculation
First, calculate the volume of your mold cavity. Standard shapes use classical geometric formulas:
- Rectangular Molds (Trays, Coasters): Length × Width × Depth
- Cylinder Molds (Tumblers, Jars): π × (Diameter / 2)² × Depth
- Sphere Molds (Orbs, Paperweights): (4/3) × π × (Diameter / 2)³
Always measure in centimeters to ensure compatibility with metric densities, as 1 cubic centimeter (cm³) is exactly equal to 1 milliliter (ml).
2. Density Conversion
Water has a density of 1.00 grams per milliliter, but liquid epoxy resins are denser. The specific gravity of standard epoxy ranges between 1.10 and 1.15 g/ml depending on the brand. This means if your mold has a volume of 100 ml, you actually need 110 to 115 grams of liquid resin. Failing to account for density results in under-filling your mold cavity.
Total Weight (grams) = Volume (ml) × Density (g/ml) × (1 + Waste Factor / 100)
3. Mix Ratio Weight Splits
Resin systems are specified as ratio by volume (typically 1:1 or 2:1) or by weight. If splitting by volume but using a scale (which is highly recommended for accuracy), you must check the technical datasheet (TDS). For most 1:1 volume epoxy systems, the density of Part A is slightly higher than Part B, allowing a direct 1:1 weight split as a close approximation. For 2:1 systems:
- Part B (Hardener) Weight: Total Weight / 3
- Part A (Resin) Weight: (Total Weight / 3) × 2
Use our interactive calculator to automate these calculations and scale your recipe for a zero-waste pouring experience.