Updated June 2026.
A “dram” of whiskey is not one US legal size. A US fluid dram is 1/8 fluid ounce (about 3.70 mL). An imperial fluid drachm is about 3.55 mL. Neither is a bar shot. UK pubs sell gin, rum, vodka, and whisky as 25 mL or 35 mL singles — one size on the premises (1988 Order, art. 3). A US shot is 1.5 ounces (44 mL). Ask for milliliters.
If someone says “a dram” without a number, do not budget a bottle on folklore. See how many mL is a shot.
Dram vs shot vs jigger
| Measure | Volume | US fl oz | What it is |
|---|---|---|---|
| US fluid dram (apothecary) | 3.70 mL | 0.125 | 1/8 US fl oz; not a modern bar pour |
| Imperial fluid drachm | 3.55 mL | 0.120 | 1/8 imperial fl oz; still not a pub pour |
| UK metric single (25 mL) | 25 mL | 0.85 | Authorized gin/rum/vodka/whisky measure |
| UK metric large single (35 mL) | 35 mL | 1.18 | The other authorized UK single |
| Irish pub pour (common) | 35.5 mL | 1.20 | Local custom; confirm the house |
| US pony | 30 mL | 1.0 | Small bar pour |
| US standard shot / NIAAA | 44 mL | 1.5 | One standard drink of 40% whiskey |
| US jigger (typical) | 44 / 30 mL | 1.5 / 1.0 | Hourglass tool, two sides |
| Tasting-room splash | 7–15 mL | 0.25–0.5 | License and house policy |
US customary: 1 fluid ounce = 8 fluid drams, so one dram = 0.125 oz. That unit still appears in some older recipes and in apothecary tables. It is not the pour in a Louisville cocktail bar. Pages that call a 1.5-ounce US shot “a dram” are using bar slang, not the fluid-dram table. TTB’s voluntary Serving Facts for spirits use 1.5 fl oz (TTB Ruling 2013-2), the same as NIAAA’s standard drink of 40% whiskey.
Scotland, Ireland, and “have a dram”
In speech, a dram is a small glass of whisky, not a pipette of 3.7 mL. The 1988 Order lists gin, rum, vodka, and whisky only. Many Scottish pubs pick 25 mL or 35 mL and post it. Gill fractions (¼, ⅕, ⅙) dropped after 31 December 1994. Ireland commonly uses 35.5 mL. None of those is a 1.5-ounce US shot. A 750 mL bottle yields 30 UK 25 mL measures, 21 of 35 mL, or about 17 US 1.5-ounce shots. See shots in 750 mL and whiskey drink-count math.
Do not cost a bottle in drams unless you define one
If a distillery flight lists “½ oz pours,” that is 15 mL, about one-third of a US shot, and about 0.33 standard drinks at 40% ABV. Barrel-proof whiskey at 60% ABV in the same half-ounce is 0.5 of a standard drink. Proof is twice ABV in the US. Read the label, then multiply.
A “dram glass” sold online can hold 2 ounces to the rim. Capacity of the glass is not the pour. Measure with a jigger if the count matters.
Costing a bottle in drams
A 750 mL fifth at 40% ABV is 16.9 US 1.5-ounce shots, or 30 UK 25 mL measures, or about 203 US fluid drams of 3.7 mL — a useless number at a bar. If a distillery sells ½-ounce tastes at $5, that is a tasting-room price, not a conversion. Barrel-proof whiskey in a ½-ounce taste still needs the ABV on the pour sheet. See shots in a fifth of whiskey when you mean a US shot.
More in our Whiskey Guide.
Sources
- US fluid dram = 1/8 US fl oz (customary apothecary). Imperial fluid drachm ≈ 3.55 mL.
- Weights and Measures (Intoxicating Liquor) Order 1988, art. 3: gin, rum, vodka, and whisky on licensed premises in 25 mL or 35 mL (same size for all four); gill fractions ended 31 Dec 1994.
- NIAAA / CDC: 1.5 oz of 40% spirits = one standard drink (14 g).
- TTB Ruling 2013-2: 1.5 fl oz distilled-spirits serving for voluntary Serving Facts.