About

Standard cylinder formulas fail when measuring barrels due to the bilge - the outward bulge in the center of the stave. This geometry requires specific integration methods (often Simpson's Rule or parabolic approximation) to accurately estimate capacity. This tool is essential for winemakers, distillers, and industrial cooperage where inventory is measured in liquid volume rather than weight.

The calculator provides simultaneous outputs in Liters, US Gallons, and Imperial Gallons. It also estimates the Full Weight of the barrel depending on the contents (Water, Oil, or Wine), using specific gravity constants to aid in logistics and shipping planning.

Formulas

We use the general approximation for a barrel with curved staves (parabolic profile).

V ≈ π h12 × (2D_bilge² + D_head²)

Where:

h = Height (Length) of the barrel.
D_bilge = Diameter at the widest point (middle).
D_head = Diameter at the lid (top/bottom).

Reference Data

Barrel Type	Typical Capacity	Material Density (Specific Gravity)
Standard Wine Barrique	225 L (59 gal)	Wine: 0.99
Cognac Cask	300 L (79 gal)	Spirits: 0.92
Whiskey Hogshead	238 L (63 gal)	Water: 1.00
Puncheon	500 L (132 gal)	Oil: 0.92

Frequently Asked Questions

The bilge contributes significantly to the volume. Ignoring the bulge and treating the barrel as a cylinder (using only head diameter) would result in a severe underestimation of capacity, often by 15-20%.

They are different units. 1 US Gallon is approx 3.785 liters, while 1 Imperial (UK) Gallon is approx 4.546 liters. This calculator calculates both simultaneously to avoid confusion.

This general formula is accurate to within 1-2% for standard wooden barrels. However, stave thickness and internal charring (in whiskey barrels) can slightly alter the actual internal volume.

Yes, it estimates the fluid weight when full. Note that this does not include the weight of the empty wooden barrel itself, which can vary from 45kg to 60kg.