How much gel medium should I add to acrylic paint?

A typical ratio is 1:1 (equal parts gel medium and paint). This extends the paint volume while maintaining body and colour intensity. You can go up to 3:1 for very transparent glazes, but the colour will be significantly lighter.

Can I add too much retarder to acrylic paint?

Yes. Retarder should never exceed 10-15% of the total paint volume. Adding too much prevents the paint from drying properly, leaving a tacky surface that may never fully cure. A little goes a long way with retarder.

What is the difference between flow improver and water?

Flow improver reduces surface tension so paint flows and levels better without weakening the paint film. Water dilutes the binder (acrylic polymer), which above 30% can cause the dried paint to be chalky, crack or fail to adhere. Always use flow improver or medium instead of excessive water.

What is pouring medium?

Pouring medium is designed for fluid art techniques where you pour paint across a surface. It has a 2:1 ratio (medium to paint) to create a self-levelling consistency while maintaining colour vibrancy and a strong paint film.

ArtCalcs

Acrylic Medium Calculator

Work out how much gel medium, retarder, flow improver or glazing medium to add to your acrylic paint.

Paint Volume

Medium Type

How We Calculate This

Medium needed = (Medium ratio / Paint ratio) × Paint volume

Recommended ratios

Gel medium: 1:1 (equal parts)
Retarder: Max 10% of paint volume
Flow improver: 20-25% of paint volume
Glazing medium: 3:1 (medium to paint)
Pouring medium: 2:1 (medium to paint)

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Last updated: February 2026

All calculations are estimates. Always verify quantities before purchasing materials.