Paint mixing calculators
Dial in basecoat, primer, clear, and reducer math for popular 2K ratios. Start with a preset batch and tweak densities for grams.
These calculators target the most searched two- and three-part ratios used in automotive refinish systems. Each preset opens the interactive MixByParts modal so you can swap to weight mixing, change reducer density, or scale the batch.
Ratios like 4:1:1, 3:2:1, or 1.3:1 split the total volume between basecoat, activator, and reducer. Toggle to “weight” mode to enter product-specific densities when grams matter.
Safety reminder: 2K products off-gas isocyanates. Wear a proper respirator, ventilate the booth, and mix only what you can spray inside the stated pot life.
Popular use cases
- Quart-ready 4:1:1 basecoat setups for common 2K systems
- High-build 3:2:1 primer surfacer scaled for multi-panel jobs
- Low-viscosity 1.3:1 clearcoat batches in half-liter spray cups
- Tiny 2:1 touch-up mixes for mini-guns and spot repairs
Common mistakes
- Ignoring pot life limits
Scaling a batch beyond its pot life leads to wasted material and poor flow. Read the tech sheet and mix only what you can spray before it kicks.
- Skipping reducer density updates
Reducers can sit around 0.90–0.96 g/mL. Update the density field when switching brands so gram conversions stay trustworthy.
- Pouring without proper PPE
Isocyanate systems demand supplied-air or fresh cartridges, gloves, and ventilation. Set safety gear before opening hardener cans.
Blend a fresh paint cup
Jump straight into a 4:1:1 mix sized for a 750 mL spray-gun cup. Tweak activator or reducer densities, switch units, or resize the batch before you spray.
Defaults: 750 mL total, weight mode with realistic 4:1:1 densities.
Paint mix presets by job type
4:1:1 basecoat batches
Preload reducer and activator defaults for common 2K base systems.
3:1:1 clearcoat sessions
Dial in activator-heavy clears for booths and production lines.
3:2:1 primer surfacer
High-build primer math sized for long-block and filler work.
5:1:1 filler primer
Dense filler mixes for bodywork stages before blocking.
2:1 urethane mixes
Versatile two-part urethane ratios for primer or sealer work.
1.3:1 low-viscosity clear
Thin clears that need precise activator control for slick finishes.
Featured calculators
FAQs
Do I mix these paint ratios by volume or weight?
Most refinish systems specify ratios by volume, but weight can improve accuracy when densities differ. Each calculator defaults to volume and lets you toggle to weight mode. Enter the densities published on your tech sheet to see grams for every part.
Can I change the total batch size?
Yes. Use the “Total volume” input in the calculator modal to resize the mix while keeping the same ratio. The preset just gives you a starting point for popular containers like quarts, liters, or gun cups.
Where do the reducer and activator densities come from?
The presets preload realistic defaults (0.93–1.35 g/mL) based on typical reducers, activators, and primers. Replace them with product-specific densities (often 0.9–1.1 g/mL) from your technical data sheet to convert the volumes into grams.
How do I manage pot life and induction times?
Many 2K primers and clears need an induction period before spraying and expire within 30–60 minutes after mixing. Use the pot-life note on your tech sheet, mix in clean cups, and only scale batches you can spray within that window to avoid clogs or orange peel.