How to Measure Resin and Hardener Accurately

Q: Should I measure epoxy resin by volume or by weight?

Always follow the method specified in your product's datasheet — it will say either 'by volume' or 'by weight.' Most consumer epoxies are measured by volume; many marine and industrial epoxies are measured by weight. Using the wrong method will give you an incorrect ratio even if the numbers match.

Q: What is the best tool for measuring epoxy resin?

For volume measurement: clear graduated mixing cups or disposable plastic graduated cylinders. For weight measurement: a digital kitchen scale accurate to 1 gram. For large pours (1 gallon+): a digital postal scale or industrial scale accurate to 5 grams. Avoid using the same cup for both parts without rinsing.

Q: Can I use a kitchen measuring cup for epoxy?

Yes, for rough estimates. Standard kitchen measuring cups are marked in cups/tablespoons, not ounces by volume — you'll need to convert. A better option is a clear plastic graduated cup marked in fl oz or mL, which gives direct volume readings without conversion math.

Accurate measurement is the foundation of every successful epoxy pour. A 5% error in your ratio can mean a permanently sticky or soft result — but it's completely avoidable with the right tools and technique. This guide covers volume vs. weight measurement, tool selection, and the exact steps to get your ratio right every time.

Enter your batch size and ratio — get exact Part A and Part B amounts instantly.

Use the Mix Ratio Calculator →

Volume vs. Weight: Which to Use?

Every epoxy product specifies its mix ratio using one of two methods. Using the wrong one will produce an incorrect ratio even when the numbers look right.

Method	How it works	Best for	Common products
By volume	Measure mL or fl oz	Most DIY projects	Tabletop, river table, casting, jewelry
By weight	Measure grams or oz (mass)	Large pours, professional use	Marine, industrial, some casting resins

Do not swap methods: Resin and hardener have different densities. A 2:1 ratio by volume is NOT the same as 2:1 by weight. If your datasheet says "by volume," measure by volume — not by weight.

Best Tools for Measuring Epoxy

For Volume Measurement

Clear graduated mixing cups: Most reliable for small batches (under 32 oz). Look for cups graduated in both fl oz and mL. Buy disposable ones — residue from Part A contaminates Part B measurements.
Separate graduated cylinders: One for Part A, one for Part B. Never share between components without rinsing.
Calibrated pour spouts: Available for gallon jugs — set a ratio stop so each pump delivers the correct volume.

For Weight Measurement

Digital kitchen scale (0.1 g accuracy): Best for small batches under 500 g. Tare (zero) the scale with your empty cup, then add Part A, tare again, then add Part B.
Digital postal/platform scale (1 g accuracy): Good for medium batches up to 5 kg. Most common choice for river table pours.
Industrial scale: For large pours (5+ kg). Overkill for most DIY projects.

Best practice: Use a dedicated cup for Part A and a dedicated cup for Part B. Contaminating Part B with even a small amount of Part A can start the curing reaction in your unmixed hardener.

Step-by-Step Measuring Process

Measuring by Volume

Calculate your required Part A and Part B amounts — use the mix ratio calculator for exact numbers
Place your mixing cup on a flat surface
Pour Part A first — read from the bottom of the meniscus (curved liquid surface)
Pour Part B into the same cup (or a separate cup then combine) — read the same way
Combine if measured separately, then mix thoroughly

Measuring by Weight

Place your mixing cup on the scale and tare to zero
Pour Part A until the target weight is reached
Tare the scale to zero again (with the Part A already in the cup)
Pour Part B until the target weight is reached
Mix thoroughly — scraping sides and bottom of the cup

Common Measurement Mistakes

Mistake	Effect	How to avoid
Reading meniscus from top, not bottom	Adds 2–5% extra per component	Always read from the bottom of the liquid curve
Using volume when product calls for weight	Wrong ratio even if numbers match	Check your product datasheet first
Using the same cup for both parts	Contamination starts premature cure	Use separate dedicated cups
Measuring in cold conditions	Resin is more viscous — sticks to cup walls	Warm resin to 75°F before measuring
Eyeballing "close enough" ratios	Off-ratio batch every time	Always use graduated tools
Not taring scale between components	Part B measurement includes Part A weight	Always tare between components when using a scale

Quick Reference: Common Ratio Amounts

For a 2:1 ratio (most common for river tables and tabletop epoxy):

Part A = Total batch × 0.667
Part B = Total batch × 0.333

Example — 32 fl oz total batch:
Part A = 21.3 fl oz | Part B = 10.7 fl oz

For a 1:1 ratio (casting resin, some art epoxy):

Part A = Part B = Total batch ÷ 2

Example — 32 fl oz total batch:
Part A = 16 fl oz | Part B = 16 fl oz

Use the mix ratio calculator for any ratio or batch size.

Frequently Asked Questions

Should I measure epoxy resin by volume or by weight?

Always follow your product's datasheet — it specifies which method to use. Most consumer epoxies are by volume; many marine and industrial products are by weight. Mixing up the methods gives an incorrect ratio even when numbers look right.

What is the best tool for measuring epoxy resin?

Clear disposable graduated cups for volume measurement, or a digital scale for weight measurement. Use separate cups for Part A and Part B. For large pours, a platform scale accurate to 1 gram is more reliable than volume cups.

Can I use a kitchen measuring cup for epoxy?

Yes, for rough reference. Standard measuring cups (cups/tablespoons) require conversion to fluid ounces. A clear plastic graduated cup marked in fl oz or mL is faster and more accurate — no math required.