Utility

Pottery Mug & Vessel Volume Calculator

Calculate how many ounces or millilitres a pottery mug, cup, or bowl holds from its inner dimensions. Supports straight mugs, tapered vessels, and rounded bowls.

Updated

Measure the inside of the rim, not the outside.

Measure from the bottom of the interior to the rim.

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Results

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Enter your measurements above and click Calculate.

How Pottery Volume Is Calculated

The calculator uses standard geometric formulas on the interior dimensions of your vessel. All measurements are of the usable space — not the outer walls.

Cylinder (straight-sided mug or cup)

V = π × r² × h

Where r = inner radius (diameter ÷ 2) and h = inner height. This is the most accurate model for straight-sided mugs and tumblers.

Tapered Vessel / Frustum

V = (π × h / 3) × (r₁² + r₁·r₂ + r₂²)

Use this for bowls or mugs where the top and bottom openings differ in diameter. Measure both the top and bottom inner diameters separately.

Hemisphere (rounded bowl)

V = (2/3) × π × r³

For half-sphere shaped bowls. Only the inner radius of the opening is needed.

Usable Capacity (85% Fill)

The usable capacity is set at 85% of the total volume — the typical fill level when drinking from a mug. This matches the real-world experience for customers and is the industry-standard reporting figure for handmade mugs.

Common reference sizes: Espresso ~60–90 mL (2–3 fl oz) · Standard mug ~300–350 mL (10–12 fl oz) · Large latte mug ~450–500 mL (15–17 fl oz) · Soup bowl ~600–900 mL (20–30 fl oz).

Frequently Asked Questions

How do I measure a mug's inner diameter accurately? expand_more
Use digital calipers for the most accurate reading. Measure across the widest point of the interior at the rim. If you don't have calipers, a ruler placed across the inside of the mug works — just ensure you measure the inner edge, not the outer wall.
Why is usable capacity shown at 85%? expand_more
Most people fill a mug to 85% of its total volume in normal use — filling to the brim risks spilling. When you list a handmade mug as "12 oz," customers expect it to comfortably hold 12 fl oz without being dangerously full. The 85% usable figure matches this real-world expectation.
My mug is not a perfect cylinder — which shape should I use? expand_more
Most wheel-thrown mugs are slightly tapered (wider at the top). Use the "Tapered" shape and measure both the top inner diameter and the bottom inner diameter separately. This gives a more accurate volume than assuming a perfect cylinder.
How does clay shrinkage affect the final volume? expand_more
Clay typically shrinks 10–14% in linear dimensions during drying and firing. This means volume shrinks by roughly (1−0.12)³ ≈ 66–72% of the wet size. If you want a fired mug to hold exactly 12 oz, the wet mug needs to be sized to hold around 17–18 oz. Use the Shrinkage Calculator to find the correct wet dimensions.