Quick answer for common home groups

The table assumes 0.5 ounces per guest per whiskey, 750 mL bottles, a 10% setup buffer, and no refills. The total milliliters column is the buffered liquid poured across the whole flight.

Bottles and liquid needed by guest count
Guests3-whiskey flight4-whiskey flight5-whiskey flight
83 bottles / 390 mL4 bottles / 520 mL5 bottles / 651 mL
103 bottles / 488 mL4 bottles / 651 mL5 bottles / 813 mL
123 bottles / 586 mL4 bottles / 781 mL5 bottles / 976 mL

Why the bottle count matches the number of whiskeys

Each sample comes from a different bottle. For 12 guests, one whiskey must provide about 195 mL including the buffer—well within a 750 mL bottle. Four different whiskeys still require four bottles because liquid from one label cannot replace another label’s sample.

The calculation

For each whiskey: guests × pour ounces × 29.5735 × 1.10. Divide that number by the bottle size and round up to a whole bottle. Then multiply by the number of distinct whiskeys in the flight.

Adjusting pour size or refills

A 0.75 or 1 ounce sample uses more liquid and more alcohol than a half-ounce sample. Put the larger size into the calculator rather than estimating. If refills may be offered, calculate them as additional pours instead of hiding them inside the setup buffer.

Alcohol context is not a ride-home answer

At 40% ABV, three, four, and five half-ounce samples equal approximately 1.0, 1.3, and 1.7 U.S. standard drinks. Strength varies, and no quantity, meal, or elapsed event time proves someone is safe to drive. Arrange sober transportation before the first pour.