[RPG] Can a horse really travel over 65 miles per day, according to the rules

dnd-5emovementtravel

Special Travel Pace (DMG p. 242–243):

  • In 1 hour, you can move a number of miles equal to your speed divided
    by 10.
  • […]
  • For a fast pace, increase the rate of travel by one-third.
  • For a slow pace, multiply the rate by two-thirds.

The Variant: Encumbrance rule (PHB, p. 176) says that carrying less than 5 times your Strength score doesn't slow your speed. And per the Lifting and Carrying rules:

For each size category above Medium, double the creature's carrying
capacity and the amount it can push, drag, or lift. For a Tiny
creature, halve these weights.

So a Riding horse has a Strength score of 16, is Large so that's up to 160 pounds (16 × 5 = 80 then 80 × 2 = 160), not slowed. It has a speed of 60 feet (or 6 miles an hour) when traveling at a normal pace. This is increased by one-third when traveling at a fast pace; 6 × 1⅓ = 8.

You can travel 8 hours a day without exhaustion. Plus you can gallop (inside that 8-hour limit) at double the normal pace (6 × 2 = 12) for 1 hour. It makes the most sense to go fast for 7 hours (7 × 8 = 56), then gallop the last hour (1 × 12 = 12), for a total of 56 + 12 = 68 miles a day.

That's 226.66% the distance that an "unslowed" human party could travel on foot at a "fast pace" (30 miles in the same time period). That's equal to a fifth of the width of Florida! To do the math, this horse could cross the whole USA in under 31 days!)

Is this right?

Seems my math is a bit off for rounding (must round down always in 5e), but SevenSidedDie's comment on GcL's answer says:

The rounding rule is just about direction of rounding. Normal math
rules are otherwise used—which means, don't round until the whole
calculation is finished. (Rounding after each step in multi-step math
calculation is verboten by the normal rules of math because it causes
errors.) Since the only change to normal math rules 5e makes is which
direction to round, normal math rules apply to 5e rules in all other
ways.

So at the very least, in 8 hours, 8 x 7 = 56, plus the one-hour gallop for 12 more, total 68? if a horse isn't limited to the same movement as that of humans with a 30-foot speed listed in PHB p. 182, which RAW, other than galloping once per "long" rest (I'm reading between the lines): IT IS.

MAJOR ADDITIONAL INFO

XGtE (Xanathar's Guide to Everything) page 80, cobblers tools note: must have cobblers tools and be proficient with them

Maintain Shoes. As part of a long rest, you can repair your companions
shoes. For the next 24 hours, up to six creatures of your choice who
wear shoes you worked on can travel up to 10 hours a day without
making saving throws to avoid exhaustion.

so 2 extra hours travel or up to 8 EXTRA miles, if you wear PC race footwear, so NOT A HORSE (38 miles total, beating horses RAW of 34 miles)

Best Answer

The calculation is incorrect, but still could be useful.

tl;dr special travel pace doesn't strictly apply as asserted and rounding goes down, but the result could be an upper limit to temper expectations.

1. Special Travel Pace doesn't strictly apply

...When a creature is traveling with a flying speed or with a speed granted by magic, an engine, or a natural force (such as wind or a water current), translate that speed into travel rates using the following rules...

A horse is neither powered by magic, an engine, nor natural force. But let's carry on with the calculation regardless, because it might be a useful upper bound of possibility.

2. Rounding in 5e is round down

Your 7.98 becomes 7.
But 6mph increased by one-third is actually 6 * 4/3 = 8mph.

3. Upper Limit

This changes the calculation to be (7hrs @8mph) + (1hrs @12mph) = 68 miles. That's maximum pace in good weather and on good terrain. Which seems pretty crazy, but let's consider that the absolute upper limit

4. Check against Phantom Steed example

The phantom steed example at the end of the special travel section gives the results for a hour of travel on a magic horse. 8hrs @13mph = 104. So the fastest pace of a mundane horse in optimal conditions while slightly misusing the rules is 60% of a magic horse. The sanity check is that this calculation still does not beat out a magic horse.

DMG p 243

Similarly, a phantom steed spell creates a magical mount with a speed of 100 feet that doesn't tire like a real horse. ... In 1 hour, the character can travel 7, 10, or 13 miles.

5. Sustained fast pace will likely end in injury and disaster

With some assumptions and optimal conditions, the numbers do work out to be very impressive, but few things in an adventure go by the numbers. Traveling at fast pace increases the risk of accident, injury, and disease. Do not expect your stories to involve regularly traveling at maximum hypothetical pace without risk.

6. Useful upper limit

This could be the upper limit of a herculean effort in order to get a message between two points. As a story point, the 65 miles distance could be considered impossible by anyone sane. But maybe... just maybe with some luck, magic, and the best horse ever it just might be doable to save the day.