A paint thinner ratio calculator takes the guesswork out of thinning miniature paints for airbrushing. The correct ratio depends on your paint type, brand, application method, and paint consistency — too thick and you get tip-dry and spatter; too thin and you lose pigment coverage. Select your options below for instant, brand-specific recommendations.
Paint Settings
Recommended Ratio
Airbrush Settings
Common Issues
How to check consistency
Dip a brush and let paint drip off the bristle tip. It should flow like skimmed milk — fluid but still slightly opaque. If it drips in thick blobs, thin more. If it runs off instantly leaving no pigment, add a drop of paint.
Quick Reference — Brand Ratios
Starting ratios for airbrushing base coats from a fresh pot
| Brand | Type | Base Coat Ratio | Recommended Thinner | PSI Range |
|---|---|---|---|---|
| Citadel | Acrylic | 1.5:1 | Airbrush Medium or IPA+water | 15–20 |
| Vallejo Model Color | Acrylic | 1:1 | Vallejo Airbrush Thinner | 15–18 |
| Vallejo Model Air | Acrylic | Ready-to-use | Minor water if needed | 12–18 |
| Tamiya | Acrylic | 1.5:1 | Tamiya X-20A Thinner | 15–20 |
| Mr. Color | Lacquer | 1:2 | Mr. Color Leveling Thinner | 18–25 |
| AK Interactive | Enamel | 1:1.5 | AK Enamel Thinner / White Spirit | 15–20 |
How to Use the Paint Thinner Ratio Calculator
Getting the right paint-to-thinner ratio is one of the most frustrating parts of learning to airbrush miniatures. Too thick and you get clogging, tip-dry, and orange-peel texture. Too thin and your paint becomes transparent and runs into recesses. This calculator gives you a reliable starting ratio based on your specific paint brand, type, and technique.
Step 1: Select your paint type and brand
Choose your paint type — acrylic, enamel, or lacquer. Then select your brand from the preset list. Different brands within the same paint type can have very different pigment concentrations and binder formulations. Citadel paints, for example, are thick and chalky compared to the self-leveling Vallejo Game Air line, which comes pre-thinned for airbrushing.
Step 2: Choose your application method
Select how you plan to apply the paint. A base coat needs more pigment density than a glaze or wash. Fine detail work requires a thinner mix to prevent clogging a 0.2mm needle. Drybrushing is the only technique where you actively want very little thinner — the paint should be almost dry when applied.
Step 3: Set the paint's current consistency
If your paint has been sitting open for a while and has thickened, select "Thick." Fresh paint from a recently opened pot is "Normal." Some lines like Vallejo Model Air are already factory-thinned — select "Thin" for those. The calculator adjusts the ratio recommendation based on the starting consistency.
Step 4: Apply the recommended settings
The output panel shows your paint-to-thinner ratio, the recommended thinner product for your brand, and airbrush settings (PSI range, needle tip size, and spray distance). Always start at the lower PSI recommendation and increase gradually — higher pressure can cause spattering and overspray on fine detail work.
Common thinning mistakes to avoid
Never thin miniature paint with tap water — mineral content causes the binder to break down and leaves a chalky, grainy finish. Always use distilled water or a dedicated thinner. Add thinner to paint one drop at a time and test on a piece of paper or card before airbrushing your model. Clean your airbrush needle between every color change to prevent cross-contamination.
Frequently Asked Questions
Is this paint thinner ratio calculator free?
Yes, completely free with no limits and no account required. All recommendations are generated instantly in your browser using established ratios used by the miniature painting community.
What is the standard paint-to-thinner ratio for airbrushing miniatures?
The most common starting ratio for acrylic miniature paint (Citadel, Vallejo Model Color) is 1:1 to 2:1 paint-to-thinner — meaning one or two drops of paint per drop of thinner. Lacquers and enamels are often thinned more aggressively, sometimes 3:1 or even 4:1 thinner to paint, especially for primer coats.
What thinner should I use with Citadel paints?
Citadel (Games Workshop) paints are acrylic and work best with the official Citadel Airbrush Medium, Lahmian Medium, or a 50/50 mix of distilled water and Isopropyl Alcohol (IPA). Avoid undiluted water alone — it breaks the binder and causes tip-drying.
What thinner should I use with Vallejo paints?
Vallejo paints are best thinned with Vallejo Airbrush Thinner or Vallejo Flow Improver diluted with distilled water. Vallejo also produces dedicated Game Air and Model Air lines that are pre-thinned for airbrush use. A 1:1 paint-to-thinner ratio is a good starting point for standard Model Color.
What PSI should I airbrush miniatures at?
For base coating miniatures, 15–20 PSI is typical. For fine detail work and thin lines, 10–15 PSI with a 0.2mm or 0.3mm needle gives the most control. Washes and glazes can be applied at lower PSI (8–12 PSI) to control flow. Lacquer primers can handle higher PSI (20–25 PSI).
How do I know if my paint is thinned correctly?
Correctly thinned acrylic paint should have the consistency of skimmed milk — thin enough to flow freely through the airbrush but not so thin that it becomes transparent in a single pass. If paint splatters at normal PSI, it is too thick. If it runs or leaves no pigment, it is too thin.
What is the difference between acrylic, enamel, and lacquer for airbrushing?
Acrylics are the most beginner-friendly — water-clean-up, low odor, and widely available. Enamels are oil-based, require mineral spirits or enamel thinner, and produce a very smooth finish but take longer to dry. Lacquers dry extremely fast, produce the hardest finish, and are used for primers and sealers — but require dedicated lacquer thinner and good ventilation.