Acrylic Pour Paint Calculator – Mix the Right Amount
Acrylic pouring looks effortless when the paint flows just right — but too little mix leaves dry patches, and too much ends up wasted in the cup.
Acrylic Pour Paint Calculator
One fluid ounce covers 25 square inches. The mix is 50% paint, 35% pouring medium and 15% water.
The secret to a smooth pour is measuring before you mix.
Your canvas size decides how much fluid you need, and the mix stays the same every time — half paint, a good share of pouring medium, and a little water.
This free acrylic pour paint calculator works out all three amounts for your canvas size, in fluid ounces and millilitres, so every pour is covered and nothing is wasted.
Guessing the amounts is where most pours go wrong. Too thin, and the colours wash out; too thick, and the paint stops moving before it reaches the edges.
It works for small canvases and large ones alike, so whether you pour a first test piece or a big wall canvas, the mix is right.
How to Use This Calculator
Example
Take a 16 by 20 inch canvas. Its area is 16 times 20, which is 320 square inches.
Divide by 25, because one fluid ounce covers 25 square inches. That gives 12.8 fluid ounces of mix in total.
Half of that is paint: 12.8 times 50 percent is 6.4 fluid ounces, which is about 189.2 millilitres.
Pouring medium is 35 percent: 12.8 times 35 percent is 4.5 fluid ounces, which is about 132.5 millilitres.
Water is 15 percent: 12.8 times 15 percent is 1.9 fluid ounces, which is about 56.8 millilitres.
So you would mix 6.4 fluid ounces of paint, 4.5 fluid ounces of pouring medium, and 1.9 fluid ounces of water for this canvas.
That is the whole mix for one 16 by 20 canvas — measure it, mix it, then pour it.
For a smaller canvas, the same steps apply — work out the area, divide by 25, then split the total into half paint, 35 percent medium, and 15 percent water.
The Bottom Line
A good pour starts with the right amounts, not with extra paint in the cup.
When the mix is half paint, a good share of medium, and a little water, it flows across the canvas, covers the corners, and dries with a smooth finish.
Measure the canvas once, let the calculator do the maths, and mix only what you need. Your paint lasts longer, your pours look better, and every canvas starts the same way.
Keep the calculator open on your phone while you pour, and write down the amounts that worked best for each canvas size.
Frequently Asked Questions
Why does the mix need medium and water?
Paint alone is too thick to flow, so the medium thins it without breaking the colour, and a little water loosens it more. Together they give a smooth, even pour.
What if my canvas is a different size?
Just enter your own width and height. The calculator works out the area, divides by 25, and splits the total into paint, medium and water for that canvas.
Can I double the mix for two canvases?
Yes — the maths scales exactly. Two 16 by 20 canvases need double the mix: 12.8 fluid ounces of paint, 9.0 of medium, and 3.8 of water.
How do I measure my canvas?
Measure the width and height in inches, edge to edge, with a tape measure. Whole inches are fine — the calculator rounds every amount to one decimal place.
What happens if I add too much water?
Too much water thins the paint too far, so the colours can look pale and the pour can crack as it dries. Stick to the amounts shown, and add water last.
Should I mix extra paint just in case?
A small extra spoonful is fine, but a whole extra batch is waste. The calculator already covers the full canvas, so trust the numbers and mix only what it shows.
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