US Fluid Drams to US Gallons (fl dr to gal)
1 US fluid dram equals 0.0009765625 US gallons exactly.
How to convert US fluid drams to US gallons
To convert US fluid drams to US gallons, multiply the number of US fluid drams by 0.0009765625. This factor is exact. To go the other way, multiply US gallons by 1,024.
US gallons = US fluid drams × 0.0009765625
Example: 10 US fluid drams = 0.009765625 US gallons.
Pints, quarts, gallons and fluid ounces differ between the US and the UK. Units are labeled 'US' or 'imperial' to avoid confusion.
About these units
US Fluid Dram (fl dr)
One eighth of a US fluid ounce (3.6967 mL). Used in old pharmacy measures.
Drachma, the Greek coin and weight, lies behind the dram. The Attic drachma weighed about 4.37 g and the Roman one about 3.41 g, and the apothecaries borrowed the name for both a weight and a liquid measure. The US fluid dram is one eighth of a US fluid ounce, 3.6966911953125 mL, and it divides into 60 minims. Its British imperial counterpart, spelled drachm in pharmacy usage from around 1900, is smaller at 3.5516 mL.
Doctors once used the dram as the size of a teaspoonful, and early nineteenth-century prescriptions assumed a teaspoon held 60 minims. By 1876 household teaspoons had grown to 80 to 85 minims, which made that shortcut unreliable for medicine. Pharmacy is now metric, but the fluid dram survives in the capacity of pill bottles and vials. In casual speech a dram of whisky is a small pour, about 25 mL in an English pub and 35 mL in Scotland, which is a different thing from the pharmacist's unit.
1 US fluid dram = 0.003696691195 liters (approximately).
Sources: Wikipedia: Fluid dram; Wikipedia: Minim (unit)
US Gallon (gal)
Exactly 231 cubic inches or 3.785411784 liters (128 US fluid ounces). About 17% smaller than the imperial gallon.
The US gallon is a survivor of English wine trade. Around 1706, a statute in Queen Anne's reign fixed the wine gallon at exactly 231 cubic inches, settling confusion among the competing gallons for wine, ale and corn. British colonies in North America used that wine gallon, and in 1824 Britain replaced all its gallons with a new imperial one while the United States kept the old measure. It was adopted as the legal US standard in 1836 and is still defined as exactly 231 cubic inches, or 3.785411784 liters.
That makes the US gallon about 17 percent smaller than the imperial gallon, a difference that explains why American and British fuel-economy figures cannot be compared directly. Everyday uses are milk jugs, paint cans and gasoline pumps. One gallon divides evenly into four quarts, eight pints, sixteen cups and 128 fluid ounces. A gallon of water weighs a little over 8 pounds, an easy figure to remember when loading a car with water jugs.
1 US gallon = 3.785411784 liters (exactly).
Sources: Wikipedia: Gallon; NIST SP 811, Appendix B.8: conversion factors for volume
Related conversions
- US gallons to US fluid drams (reverse)
- US fluid drams to liters
- US fluid drams to milliliters
- US fluid drams to US cups
- US fluid drams to US fluid ounces
- Liters to US gallons
- Milliliters to US gallons
- US cups to US gallons
- US fluid ounces to US gallons
- Cubic meters to US gallons
- Cubic centimeters to US gallons
- US quarts to US gallons
- US pints to US gallons
- US tablespoons to US gallons
- US teaspoons to US gallons
- Metric cups to US gallons
- Metric tablespoons to US gallons
See all volume units.