While doing research into the amounts of various resources necessary to support a fantasy world population, I discovered that I needed to make various decisions about how to interpret the data and how to modify it to account for the differences that exist in a fantasy world. Some of these decisions revolve around which set of units to use.

Many units of measure vary from system to system. The term ounce may refer to 28.3495231 international avoirdupois ounces or 31.1034768 troy ounces or 28.0668 Maria Theresa ounces. Therefore, before I started, I had to define some basic units. Note that these are simply the definitions that I have chosen to use and any term defined here may or may not match any actual value. Some terms have been adjusted to make the numbers easier to deal with. For instance, a gallon of water has been re-defined to weigh exactly 8 pounds and one cubic foot contains exactly 7.5 gallons.

If using inaccurate figures bothers you, by all means look up and use the true values. This post isn’t designed to be a recommendation as much as simply being documentation of what values I am using in order that I may then reference it in a future post. As such, it may be updated without notice as I add or alter my definitions.

Weight

15 grains = 1 gram
28 grams = 1 ounce
16 ounces = 1 pound
2,000 pounds = 1 ton

Volume

1 dram = ¼ tablespoon
3 teaspoons = 1 tablespoon
1 tablespoon = ½ fluid ounce
16 tablespoons = 1 cup = 8 fluid ounces
2 cups = 1 pint = 16 fluid ounces
2 pints = 1 quart = 32 fluid ounces
4 quarts = 1 gallon = 128 fluid ounces
7.5 quarts = 1 peck
7.5 gallons = 4 pecks = 1 bushel

Volume Conversions

1 cubic foot = 7.5 gallons = 960 fluid ounces
1 gallon = 230.4 cubic inches = 0.13333 cubic feet
1 peck = ¼ cubic foot = 432 cubic inches
1 bushel = 1 cubic foot = 1728 cubic inches

Density of Water

1 gallon of water = 8 pounds
1 cubic foot of water = 60 pounds

Standard Containers

1 cask = 5 gallons
1 keg = 20 gallons
1 barrel = 50 gallon
1 tun (huge barrel) = 250 gallons
1 basket = 4 pecks = 1 bushel = 1 cubic foot

Distance

12 inches = 1 foot
3 feet = 1 yard
5,280 feet = 1,760 yards = 1 mile
3 miles = 1 league

Area

1 acre = 44,605.44 square feet (211.2 feet x 211.2 feet)
1 acre is the amount of land one ox can plow in one day
1 square mile = 625 acres (25 rows of 25 acres)