Double Magnum
Double magnum wine bottle meaning
A double magnum is common still-wine shorthand for a 3-liter bottle, exactly equal to four 750 mL bottles. At nominal capacity, that is about 20.3 five-ounce volume units.
For Champagne, the official Comité Champagne list calls the same 3 L volume a Jeroboam. The name therefore needs a wine and regional context; the stated liters remain the reliable conversion.
Use the wine bottle sizes chart to compare 3 L with magnum, the 4.5 L Rehoboam, Methuselah, and the larger Champagne sequence.
Source: Comité Champagne bottle-size FAQ.