Free Paint Pouring Calculator: How Much Paint to Mix

Why You Need a Paint Pouring Calculator for Your Next Project

This free paint pouring calculator tells you how much paint to mix for your canvas, in inches or centimeters.

Figuring out how much paint to mix is one of the trickiest parts of pouring. Mix too much and you waste paint and time. Mix too little and you may run short before the canvas is covered. When I first started, every video told me to “just eyeball it” or “use about this much,” and I didn’t feel confident until I understood what eyeballing actually meant.

That’s why I made these calculators. There are four: one for squares and rectangles and one for circles, each in inches and in centimeters. Enter your measurements and you’ll get a solid starting amount of fluid paint (paint, pouring medium, and water mixed together).

Step-by-Step Guide to Using Your FREE Paint Pouring Calculator

1. Pick your calculator. Choose rectangle/square or circle, in inches or centimeters, whichever matches how you measured.
2. Enter your surface size. For a rectangle or square, enter the height and width. For a circle, enter the diameter. Then add the depth of the sides if you want to cover them. Sides in decimals: 1/2″ = 0.5 and 3/4″ = 0.75. If you’re not covering the sides, enter 0.
3. Read your total. The calculator gives you the approximate amount of fluid paint you need, in fluid ounces if you measured in inches or milliliters if you measured in centimeters.
4. Mix a little extra. Treat the number as a solid starting point. A small cushion gives you room for your design and for pour-to-pour differences.

Why Use a Paint Pouring Calculator?

More repeatable pours. When you use similar amounts on similar canvases, it’s easier to compare your results and repeat what worked.

Less waste. You mix close to what you need instead of a big batch that ends up in the trash.

More confidence. You start each pour with a number instead of a guess, so your attention can go to your colors and your technique.

A faster start. Measure, calculate, mix. No trial and error at the mixing cups.

Tips for using the Paint Pouring Calculators

• The calculations above are provided as approximate measurements needed of fluid paint to complete your project, including any base paint layers you start with.
• Fluid paint is defined as a combination of acrylic paint, water, and a pouring medium.
• If you’re not covering the sides, enter 0 in the Depth field.
• Different variables will alter these measurements, such as paint consistency and the pouring technique used. If you use a thicker consistency of mixed paint, you will need to add between 5%-10% more paint to the calculated measurement.
• You may also reference my “How much acrylic paint to cover canvas chart” below.

Did you know that one of the most common problems with beginners is leaving too much paint on their canvas? This can cause all sorts of problems such as cracking and crazing!

Have you been wondering what is best to use in your paint mixes? Floetrol, Glue-all, or Water?  I decided to record a comparison experiment to show you the differences in using each as a pouring medium for the Acrylic Paint Pouring Techniques. During this experiment, I learned a lot about how each of the pouring mediums works with the Acrylic Paint Pouring Techniques, and I have a better understanding of how they work with each other.

QUICK GUIDE for Common Canvas Surface Sizes

For your convenience, I am also providing a chart that I use with some common canvas sizes. This chart uses the same formulas as the Paint Pouring Calculators above, but it provides quicker AT GLANCE information for the flat surface. This chart does not include your surface’s side measurements; you will need to add that measurement. Here is my how much paint for the acrylic pour chart:

Flat surface only. Use the calculators above to add your sides. Milliliters are converted at 29.57 ml per fluid ounce.

EXAMPLE: How much does 2 oz of acrylic paint cover? A good rule of thumb is to use approximately 1 ounce of paint to 25 square inches of surface coverage. Using this as a guide, 2 oz of acrylic paint would cover 50 square inches of the surface.

How to Mix Paint for Pouring

Once the calculator gives you a total, here’s how to turn it into paint and pouring medium. This page is for acrylic pouring, so these steps are for acrylic paint.

1. Pick your starting ratio. For craft paints, I start with 1 part paint to 2 parts pouring medium. For thicker, heavy-body paints, I start with 1 part paint to 3 parts pouring medium. Every brand behaves a little differently, so treat these as starting points. My Acrylic Pouring Ratios guide has ratios by brand.
2. Do the math with your total. Say you have an 8″ x 10″ canvas. The chart says 3.2 oz. At 1:2, that’s roughly 1 oz of paint and 2 oz of pouring medium, rounded up a little to reach 3.2 oz.
3. Mix it well. Stir with a stick or palette knife and scrape the sides and bottom of the cup so everything is blended.
4. Check the consistency. You’re looking for warm honey. When you lift your stir stick, the paint should flow in a smooth, continuous stream and sink back into the cup within a few seconds.
5. Adjust in small steps. If it’s too thick, add a little pouring medium. If it’s too thin, add a little paint. Water is for fine-tuning only: a few drops at a time, then mix and check again.
6. Add silicone oil if you want it. It’s optional. Getting your ratio and consistency right does more for cells than any additive.
7. Pour. Try a dirty pour or a flip cup to start.

Wear gloves and a mask when you work with paint and pouring supplies, and keep the room well ventilated.

Paint Pouring Calculator FAQ

How much paint do I need for a 12″ x 12″ canvas? About 5.76 fluid ounces (roughly 170 ml) for the top surface. If you’re covering the sides too, add them with the calculator above.

If I need 20 oz of mixed paint, how much paint and how much pouring medium do I use? It depends on your ratio. At 1 part paint to 3 parts pouring medium, which works well for thicker, heavy-body paints, 20 oz is 5 oz of paint and 15 oz of pouring medium. With craft paints I start at 1 part paint to 2 parts pouring medium, which is about 6 2/3 oz of paint and 13 1/3 oz of medium. Then I add paint, water, or medium as needed.

Does the calculator include my base coat? Yes. The estimate includes any base layer you start with, so whatever you use for your base counts toward the total. Mix that much less for your pour colors.

Why do my colors keep turning muddy? Thin paint is a common cause. When paint is too thin, the colors blend together too easily and lose their definition. Try mixing to that warm honey consistency, and check out My Favorite 5 Color Combinations for pairings that stay clean.

If you’d like someone to walk through the mixing, ratios, and consistency with you, the Academy Membership gives you full access to my courses and the community for $15/month.