While this question is specifically about D&D fifth edition, I realise it can be relevant to any system which doesn't use the metric system.

I live in Europe, and I have been playing D&D since my early teenage years. Thinking about it now, I've never really been able to work accurately with distances, weights, or any other units of measurement used in the book, them not being in the metric system. As a player, when I enquire the DM about something related to distance, I get a reply in units I can understand, so that's not an issue. But when consulting the Player's Handbook, I always struggle.

For those of you who are accustomed to the metric system, how do you deal with this annoying aspect? Do you annotate your books? Have you developed a conversion method that works reliably and doesn't disturb the game's flow?

  • 3
    \$\begingroup\$ Out of curiosity, what imperial conversions are you performing in DnD 5th? Weights should all be in pounds. If a weight is presented in tonnes, you can't carry it, so don't bother converting. Currency is metric. Distances are feet and miles, but you should never have to convert between them. If you intend to travel a few hundred ft, your speed is 30 ft/round or 60 if you dash. If you are travelling a longer distance, it's 3 miles per hour, which isn't what you get if you convert either 30 or 60 ft/6 seconds into miles/hour. \$\endgroup\$ – Scott Aug 30 '17 at 5:13
  • 8
    \$\begingroup\$ @Scott yes, working with imperial units is no problem. But if all of your players have never heard of feet as a unit, they have absolutely no instinctual grasp on what you tell them. If I say to my players "the BBEG is a ten foot scaly monster" all they infer from it is: it's probably big, because the DM tries to describe something scary. If I say "it's a 3m scaly monster" they instantly know how big it really is, they can compare it to other stuff, because they know what 3m are. \$\endgroup\$ – TBP Aug 30 '17 at 7:49
  • 1
    \$\begingroup\$ I know this is an old question, but it also seems like a survey-based one with no way to choose a single "best" answer; it just asks "how do you (metric readers) deal with imperial measurements?". \$\endgroup\$ – V2Blast Jan 24 '19 at 20:42

Coming from Sweden, this is obviously an issue for me as well. Personally, I just make rough conversions on the fly as needed, but communicate everything to the players in the given units (inches, feet, yards, lbs etc).

Some basic conversion that I use (that are incorrect, but close enough to get a feel for the numbers):

  • 1 lbs = 1/2 kg, or 1 kg = 2 lbs.
  • 1 inch = 2.5 cm
  • 1 foot = 30 cm
  • 1 yard = 1 meter
  • 1 mile = 1.5 km.

I mostly feel that the imperial system works pretty well in fantasy RPGs, since it feels like an old timey way of thought and adds some flavor.

| improve this answer | |
  • 57
    \$\begingroup\$ When your character's throwing range with a table is 1 mile, you did some serious min-maxing :) \$\endgroup\$ – Philipp Aug 28 '17 at 12:06
  • 21
    \$\begingroup\$ Honestly, I'd just say that 5 feet = 2 meters and 1 mile = 2km. It's all fantasy anyway rounding in favor of simplicity needn't break immersion. \$\endgroup\$ – aslum Aug 28 '17 at 13:08
  • 14
    \$\begingroup\$ @carl True, on the other hand if you just translate overland speed from 30mph to 60kph and change the distance between two towns from 30 miles to 60 km it still takes exactly an hour to get between them... yeah the scale is a little different, but for game purposes it doesn't matter to much. \$\endgroup\$ – aslum Aug 28 '17 at 18:41
  • 5
    \$\begingroup\$ The french books use the following conversion, at least for feet/miles: 5 ft = 1,5 m = 1 unit (3.5 map units) 1 mile = 1,5 km Coming from 3.5 where I was used to think in units of 1,5m, the conversion to 5 ft for my english 5e book does not bother too much \$\endgroup\$ – Jupotter Aug 29 '17 at 12:06
  • \$\begingroup\$ as 5th edition specifically uses many increments of 5 ft (especially for grid use), how do you approximate that? 1.5 meters? \$\endgroup\$ – goodguy5 Jan 24 '19 at 14:26

The Russian variant of PHB 3.5 page 331 has the following conversion table (I'm translating it, because it is originally in Russian):

1 gallon = 4 litres

1 inch = 2.5 cm

1 mile = 1.5 km

1 oz = 30 g

1 lb = 1/2 kg

1 foot = 1/3 meters or 30 cm

1 yard = 1 meter

I guess nothing has changed in the metric system since then, thus the same conversion table is valid for D&D 5e too.

| improve this answer | |
  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$ – mxyzplk - SE stop being evil Aug 30 '17 at 0:53
  • \$\begingroup\$ Please note that the original post has been updated to remove the second part about "why is it this way." I don't know that you need to edit your answer--the last paragraph doesn't seem out of place--but I wanted to make sure you knew. \$\endgroup\$ – nitsua60 Aug 30 '17 at 14:48
  • \$\begingroup\$ @nitsua60 Thanks! I'll remove it. It is just my speculations and don't add much to the answer. \$\endgroup\$ – Ols Aug 30 '17 at 16:32

I live in the United States and used to run Hero System for many years, which is metric based. With very few cases, it really doesn't matter what the units are, only how they interact. Being semi-logarithmic in nature, the Hero System lends itself well to a decimal-based measurement system, but that's immaterial.

It's not hard to make the very few conversions that are absolutely necessary. We don't really need to know that the maximum range of the D&D longbow is 600 feet, or 200 yards or 182.88 meters. It's 600 units, that interact with the other units chosen by the game system for things like movement, area of effect and so forth. It's very rare that you would need to know the real world weight of an arbelast, and you would have to look it up anyway, so it's far more important that the weight be given in a way that interacts with the rest of the system.

As for a converted version of the rulebooks, the relationship of units is very hard baked into the mechanics (see the reasoning for Hero above). A simple conversion would lead to needless complexity (like the long bow range above), or rough approximations would require re-working formulas for things like jumping distance or carrying capacity. Furthermore, D&D is a world-wide phenomenon, with organized play. Supporting two incompatible editions would be nightmarish.

| improve this answer | |

As has been mentioned, the problem is often not so much the exact conversion, but an intuitive understanding of what those numbers mean.

When we started our last D&D campaign, we went through the numbers on our character sheets and figured out corresponding weights and distances:

  • "The dwarf has dark vision and can see 60ft. That's from here to the road."
  • "The range on the longbow is 150ft, that gets you from here to that fence."
  • "My carry weight is 30 lb, which is how much an airline hold bag weighs."

With some others being added as needed:

  • "The dungeon is x miles' walk from the town. That's from here to [familiar location]."
  • "An owlbear is ten foot tall, which is about one storey of this building."

Obviously this isn't possible for every number in every Imperial unit, but just figuring out the most commonly used stats helps a lot with intuition. Especially if you are playing in a regular location. Then when the DM says "The far wall of the cave is 90ft away", you can glance out of the window and think "Oh, between the road and the fence. I see how far that is."

(My parents would use this technique when I was a child to explain the size of marine animals. Without anything else on screen for perspective, it's hard to grasp what a 9m wide manta ray actually would look like in person. This has since been very useful in picturing dragon sizes...)

| improve this answer | |

Personally I stopped bothering with converting unless it is absolutely needed. I use whatever units the game provides for rules related things and metric (or general descriptions) when it comes to 'fluff' like weight and height of a character. It can make things a bit more abstract at times, but I find it works really well once you get used to it. I find it less distracting than losing time continously converting at least. A minor benifit is that since the game not a perfect simulation of reality anyway, it sometimes helps to seperate the rules and the descriptions.

Two examples:

Size, Distance and Speed

All the books and adventures use the same measurements for distance. Therefore, I know that if I always use the ones in the books, I am being consistent. To get an idea of how to visualize things, I just compare and generalize things to get an idea of what things look like. For example: if the monster is standing 20 feet away and I have 30 feet of movement, I know enough: it is well out of my melee reach, but I can get there with a handful of steps during my turn. I can convert 20 feet to 6m, but I don't see that much added value in knowing the exact distance.

Using (5 feet) squares as a simplification tends to work great for movement and scale. This is the most Obvious when using a map with a grid, but I find that it helps even if you do not use a grid. It gives you smaller units to work with when calculating distances (which makes the math easier): the monster is 4 squares away and I have 6 squares of movement during my turn. Even when not using a map, a square is an easy shorthand for describing 'the space a single small or medium person controls during battle'. Additionally: conversion from squares to meters is fairly easy (5 feet is= 1.5m).

Weight, Objects and Equipment

For the game, weight only matters in specific occasions like carrying capacity. When weight matters for the rules (like calculating carrying capacity), I use the book values. Occasionlly you will need a conversion, like when trying to lift a PC with a levitiation spell that has a limit in pounds. Most of the time though, you can just wing it (putting a reasonable height and weight on a human NPC is not that hard) or just use broad descriptions that do not require exact values (the NPC is tall/short/fat/skinny/...). For equipment you can use real life objects to get an idea of what they look like. If at any point you need stats, just pick something that matches in the game.

| improve this answer | |

D&D uses the imperial system not only because the USA (where it was written) uses it, but because meters seems modern.

D&D is evokes an archaic feel.

If you want to keep that feel, but want units you can understand, try this:

Simply replace 5' by 1 yard (which is 3'). This shortens a bunch of distances, but no so much as anyone would notice. A yard is about a meter, or the distance between your nose and your finger when you stretch out your arm, or the length of a stride.

Speeds are a bit slower, combat a bit more crowded, creatures a touch smaller, weapons don't reach as far, buildings a bit smaller. But none of these amounts are large enough that they'll stretch belief.

If you are really worried about people moving 60% as fast, make combat rounds 4 seconds instead of 6. But I wouldn't bother.

Alternatively, replace 5' with 2 yards = 2 meters. I'd argue against this, because almost all distance measurements in D&D are in multiples of 5', and the conversion to yards without the *2 makes things simpler.

If you don't want the feel and just want meters, use meters like I suggested you use yards above.

A fun part of using yards is that you can tell your players what it is, and explain that when you say something is 10 yards away you don't mean a measuring tape, but rather their best guess at pace counting.

| improve this answer | |
  • \$\begingroup\$ but because meters seems modern. Source? \$\endgroup\$ – JBC Aug 28 '17 at 16:01
  • \$\begingroup\$ Rather than stating that meters seems modern, I would approach from the actual concepts used for deciding the distances. Why Imperial seems more archaic, specifically. For example, an inch was defined as the length of three grains of barley laid end to end (old legal definition). en.wikipedia.org/wiki/English_units#Length This shows how they were measured such that an 'uneducated commoner' can use these measurements. \$\endgroup\$ – Aviose Aug 28 '17 at 19:52
  • 1
    \$\begingroup\$ For what it's worth, the United States does not use the Imperial system. The systems are close enough for game purposes, but see en.wikipedia.org/wiki/United_States_customary_units for a list of differences. \$\endgroup\$ – Perkins Aug 28 '17 at 21:07
  • \$\begingroup\$ This question was revised to no longer ask why the system uses imperial instead of metric or doesn't have a metric edition. \$\endgroup\$ – doppelgreener Aug 30 '17 at 18:33

Abstract it out or approximate the simplest way you can

Around the tables I have played at, we dealt with it with heavy dose of approximation. Most of the time, what the player really needs is "is the target too far for my spell/bow", the GM should use this to his advantage to adapt the distance. As a GM, part of the job is to to adjust the situations so that the mechanics work the way you want. Distance is just another variable.

In the case of feet to meter transition and precise distance, most games I've played used a grid approximation. When a better approximation was needed,we converted 5ft to 1m. Sometime adding a loose approximation of half the distance to get a better precision.

In combat with a grid, we would count squares for moves and range. So walking walking distance was measured as 6 squares instead of 30ft.

In combat without grid, we would count distance as multiple of a turn's walking distance. A target is either in melee (<10ft), in walking range (<30ft), charge range (<60ft), bow range (<160ft if memory serves) or not in combat (anything more than that)

For travel and distances between places in the world, the GM would express it in time at walking speed. So that a given point of interest would be at "3 days of walking" or "A day by boat". Inconsistencies between modes of transportation or different journeys were lampshaded respectively via different paths or changing conditions.

In roleplay scenes, distance ended up being abstracted. Instead of "How far is the cook from me?", we would ask the GM :

  • Can I use charm person on the cook from where I am?

  • How far can you cast?

  • 30ft.

  • No, it's a really big room you're in.

Again, if we want a mental image of how far things were, divide by 5 and we have the In-universe distance.

As for why the imperial system is still in use, I would guess that they keep it because it's always been that way. But when the first editions came out, the US didn't use the metric system and the UK (see KorvinStarmast's comment below) had not yet widely accepted it.

| improve this answer | |
  • \$\begingroup\$ When the game came out(1974), the Brits had not yet gone metric (road signs were still in miles, but I think the move in that direction had begun) . They had already crossed their currency over from shillings and pence and pounds to the decimal pence to pounds method. I was in the UK in 1971 and, having been familiar with shillings, pounds and pence, as well as the decimal Deutschmark, just had to work it out in my head. \$\endgroup\$ – KorvinStarmast Aug 30 '17 at 13:49
  • \$\begingroup\$ Please note that the original post has been updated to remove the second part about "why is it this way." I don't know that you need to edit your answer much--the last paragraph doesn't seem out of place--but there's no longer an obvious "second point" to respond to. \$\endgroup\$ – nitsua60 Aug 30 '17 at 14:50
  • \$\begingroup\$ Thanks for the intel you two. I didn't have time to check it since I wrote it. \$\endgroup\$ – 3C273 Sep 1 '17 at 0:51
  • \$\begingroup\$ Probably not worth much, but rereading it, I realised it was very hastily written. I've reformulated a few points. \$\endgroup\$ – 3C273 Sep 1 '17 at 1:09

I tried to get used to using imperial measurements when playing the game. This strategy never really worked that well.

I wouldn't say it was a total failure, though. Feet generally aren't a problem for me any more, as most distances used in the game are multiples of five feet, and five feet is "about one dude tall," so all I have to do is convert squares of movement into dudes lying down.

I've given up on ever understanding pounds, though. Fortunately, my campaign is such that I rarely need to know how much pounds are: Most of the things my players carry around indefinitely are standard items of equipment with listed weights. They occasionally pick up other things, but rarely carry them long enough for their precise weight to become important.

Anyway, I eventually gave up on using pounds and switched to using a simplified system of encumbrance I imported from the Adventurer Conqueror King System.

| improve this answer | |

Get metric books instead

While not usually an option for small publishers, larger game companies often offer translated and/or localized books for various regions. For post-TSR D&D, at least, this has in the past included a localization for the UK that, among other smaller changes, converted the rules into the metric system.

Because the localizations use conversions of convenience, different regional printings have slightly different results when calculating e.g. optimal spell damage not-on-a-grid but these small differences are not supposed to cause problems for gameplay.

For D&D 5e in particular, there's not currently any real UK localization, but there are books in Spanish, French, Italian, and German that have the metric system used instead. There is a Portuguese translation as well but there are ethical reasons to avoid purchasing it, so I can't in good conscience recommend that one.

| improve this answer | |
  • \$\begingroup\$ "There is a Portuguese translation as well but there are ethical reasons to avoid purchasing it, so I can't in good conscience recommend that one." - What are these reasons? Is it an unofficial PDF or something? \$\endgroup\$ – V2Blast Jan 24 '19 at 21:17
  • \$\begingroup\$ @V2Blast added link to a news site explaning the background of the controversy. \$\endgroup\$ – Please stop being evil Jan 24 '19 at 21:25
  • \$\begingroup\$ "there's not currently any real UK localization" — speaking as a Brit, I'm quite comfortable with metric lengths and the only weight that really matters is the pound, which is a small bag of sugar. \$\endgroup\$ – Quentin Jan 24 '19 at 21:57
  • \$\begingroup\$ @Quentin Other way around. I would expect a UK localization to use metric. Is that not a thing? \$\endgroup\$ – Please stop being evil Jan 24 '19 at 22:32
  • \$\begingroup\$ @thedarkwanderer — We have an odd mix of imperial and metric for distances here … mostly because nobody wants to convert all the road signs into KM. I grew up with rulers that are marked in metric and imperial so converting between 30cm = 1' and 2.5cm = 1" is instinctive. \$\endgroup\$ – Quentin Jan 24 '19 at 22:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy