In OD&D's "Underworld & Wilderness Adventures" movement rates are given as numbers of hexes per day which can be travelled according to type. This is followed by a suggested scale of 5 miles per hex. So, a figure on foot who has a rate of 3 hexes of movement per day would therefore travel 15 miles in a day. This works fine when making longer journeys on a typical referee's wilderness map, but what about if a journey is being taken to reach somewhere that is only a few miles away? For purposes of time keeping you may wish to compute how much time this would take.

OD&D Movement Speeds as Miles per Hour

To calculate how many miles per hour a figure can move first you need to figure out how many hours are in a typical day. Presuming a medieval European setting the day would be measured from dawn until dusk, so we are really only dealing with the daylight hours between. For a temperate climate you would typically have about 12 hours of daylight in spring, 16 in summer, perhaps 10 in autumn and 8 in winter. We can presume that if Gary Gygax wanted to differentiate in this way he would have provided variant movement rates based on the season, but he didn't so the presumption is that an abstraction is what we are looking for. So if we look at the average we might say that typically a day has 12 hours of daylight. Using this as a base we can then easily extrapolate from there. For example, a figure on foot can move 15 miles per day, or (15/12=1.25) 1.25 miles per hour. These calculations don't always come out so precise as that. The draft horse moves 25 miles per day, which computes to 2.08 miles per hour. On those cases the best solution, I think, is to round down to the nearest quarter. Thus, we end up with the following:

                 Miles/hour:

                 Clear    Woods    River    Swamp    Mtns    Desert

Man on Foot      1.25     0.5      0.25     0.25     0.25    0.5
Wagon or Cart    1.5      0.75     0.5      0.5      0.5     0.75
Draft Horse      2        1        0.5      0.5      0.5     1
Heavy Horse      2.5      1.25     0.75     0.75     0.75    1.25
Medium Horse     3.25     1.5      1        1        1       1.5
Light Horse      4        2        1.25     1.25     1.2     2
Raft             --       4        1.25     --       --      --
Boat             --       --       6.25     2        --      --
Merchant         --       --       5        --       --      --
Galley           --       --       8.25     2.5      --      --

FLYING SPEEDS (miles/hour):

                 Hippo-                                     Djinn/Air
Dragon  Griffon  griff   Roc  Pegasus  Broom  Carpet Efreet Elem.

10      12.5     16.5    20   20       16.5   12.5   8.25   12.5

Let me know what you think.