I know my title question seems a little confusing, but let me explain.

I was looking for some measurements on dragons seeing as I'm doing Tyranny of Dragons and I wanted to have some rough measurements in mind to play around with. A friend of mine said that he had a Draconomicon from 3.5 and could just take some pictures of the size charts and send them to me.
I was playing around with the charts. I thought I had it figured out on what I was going to do, but then I realized that I had no idea how they calculated the rest of the measurements.

Now, for the record, I am bad with numbers, and I mean REALLY bad with numbers and math. Try as I might, I just couldn't figure it out for the life of me, and when I thought I had it, it just didn't seem to work for other dragons.

I'm here to ask you all to help me figure out how they got the measurements they did; what equations or whatever that they might have used or they actually used. I'm not sure what all I'm allowed to post here, so I will try to be as detailed, yet vague as I possibly can.

I have a Black Dragon, The Overall Length that I chose to have is 56ft.

The chart also lists: -Body Length -Neck Length -Tail Length -Body Width -Standing Height -Max. Wingspan -Min. Wingspan -Weight

I'm not too worried on the weight on them, because I don't really think it's going to matter, but I know that a size can make or break how epic an encounter feels. I want to know how to get all those other equations from the Overall Length that I have made up. Again, I know my question is a little confusing, and I know the explanation is long; but I thank everyone for taking the time to read it and answering this. I really do appreciate it!

  • 1
    \$\begingroup\$ To clarify, you're looking at the chart on Page 37, and asking how to make a new row of entries for an overall length of 56 ft? \$\endgroup\$
    – Novak
    Commented Jun 30, 2023 at 3:07
  • \$\begingroup\$ I think? In fairness he only sent me a picture of the measurements charts, not the whole pages. So I can't tell you for sure what page it's on. Regardless, yes, I'm asking how to make a new row of entries for the overall length of 56ft. If there are equations on how to do that, it would be good for future use. \$\endgroup\$ Commented Jun 30, 2023 at 3:11

2 Answers 2


Just use the measurements given for the Huge dragon

First off, you overestimate how important the exact size is for your fun and epic encounters. If you describe how the paladin heroically smites into the dragons flank for 47 damage, nobody is going to ask you how large the dragons standing height is, and at what exact height they made the cut, ever.

Of course do this if you enjoy doing it. At the same time, it may help you to understand that for you as a DM, your prep time is a valuable resource. Managing it by spending it on the things that matter for play helps you be a better DM. (And learning what these are, from experience, player feedback and reading is part of becoming better at it).

Here are the full size classes for Huge, and for the one it is growing towards, Gargantuan (p. 37 Draconomicon):

Size Overall Body Neck Tail Width Height Wings Min Wings Weight
Huge 55 ft. 16 ft. 15 ft. 24 ft. 8 ft. 12 ft. 60 ft. 30 ft. 20,000 lb.
Gargantuan 85 ft. 24 ft. 23 ft. 38 ft. 10 ft. 16 ft. 80 ft. 40 ft. 160,000 lb.

And for your dragon of 56 feet, there is a mere 1 foot of difference to the listed numbers. Really, if you are that close to the listed size, even if you normally would do this, just use the 55 feet dragon measurements and say "about" when you use them.

With that out of the way, here is the procedure and a worked example for the black dragon.

  1. Figure out in which size category your dragon is. It is the first one for which your dragon length is equal or larger to the listed size in the table. Here, your dragon is Huge.

  2. Divide the size for your dragon by the size for the dragon listed in the category to get a "scaling factor" that tells you, how much larger your dragon is, relatively. Here 56 / 55 = about 1.018.

  3. Multiply each size for the category by the scaling factor.

Doing this for each category gives these measurements for your dragon:

Size Overall Body Neck Tail Width Height Wings Min Wings Weight
Huge 56 ft. 16.28 ft. 15.27 ft. 24.4 ft. 8.1 ft. 12.2 ft. 61.1 ft. 30.5 ft. 21,100 lb.*

* Weight would not scale linearly with length, because it is based on three-dimensional volume. So you have to multiply with the scaling factor 3 times, one for each dimension.

P.S. Note that this assumes all measurements grow the same relative amount between size categories. This is actually not the case, for example, overall length grows from 55 to 85 feet, or about 55%, a scaling factor of 1.55, while wingspan only grows from 60 to 80 feet, or about 33%, a scaling factor of 1.33.

This therefore actually does not get to the measurements for a Gargantuan dragon, if you just use the scaling factor from length everywhere. For example applying the 1.55 scaling factor to the 60 ft. wingspan results in a predicted wingspan of 92.7 feet, not the 80 feet in the table.

A more exact method for categories below Gargantuan would be:

  1. Determine the overall size difference between the categories, here 85 - 55 = 30 feet. Determine the difference for your dragon, here 56 - 55 = 1 foot. Determine the ratio of smaller to larger, here 1 / 30.

  2. For each category determine the difference, for example for wingspan, 80 - 60 = 20. Multiply this with the ratio, and add it to the smaller measurement one, here 20 x 1/30 + 60 = 60.7 ft.

This procedure would not allow you to compute for the exact numbers of the Gargantuan dragon (because you would have to divide by 0, which is undefined), but it will ensure that you get very close to the Gargantuan measurements, for a dragon that is nearly Gargantuan, say 84 feet: 84-55 = 29, ratio 29/30. Wingspan = 80 x 29/30 = 77.3 ft.

This is a lot more work though.


I'm going to give a little more information than you asked for, with a little extra background, because in my opinion it will make the overall answer more complete for others with similar questions.

This answer is also what-I-would-do, and is definitely good-enough-for-government-work, but not guaranteed to be what the writers would do in my place. It will be pretty close, though.

First the background: In general, there are three types of measurements (or entries in that or any similar table) that you will be worried about:

  • Measurements related to length: Anything that you would measure (or that a table calls out) in units of length such as feet, inches, meters, yards, etc are measurements of length. Everything on the table I think you are looking at is a measurement of length except weight. Yes, even the widths and heights are considered "lengths" because they are measured in feet. The idea is, anything that can be measured directly with a tape measure.

  • Measurements related to area: There are none on the table I think you're looking at, but these would be measured in units like square feet, square inches, etc. An example (made up, not from your table) would be the total area of the wings or the belly, because that might determine how many garments or suits of armor you could make.

  • Measurements related to volume or weight: Measurements of volume will have units like cubic feet, cubic inches, etc. Measurements of weight (or mass) will have units like pounds, kilograms, ounces, etc. For the purposes of this answer, volume and weight are treated the same.

Second, the procedure:

  1. Determine the closest row in the table to what you want. In this case, you want an overall length of 56 feet, and the closest row in the table is 55 feet. See caveat below.

  2. Determine a "linear scaling factor" as follows: divide your desired value by closest value. If your desired value is larger, the scaling factor will be greater than one, otherwise it will be less than one. In this case, 56/55 = 1.018 after rounding off.

  3. For each "length measurement" in the closest-to row, multiply by your scaling factor. So the neck length in the row for 55 ft is 15 ft. Take that and multiply by your scaling factor to get 15.27 ft.

  4. For each "area measurement" in the closest-to row, multiply by your scaling factor twice. You don't have any in that table, but if you had a "wing area" measurement of 2700 square feet, you would multiply by 1.018 twice to get 2799 square feet. (Another way to say this is that you are multiplying by the square of your scaling factor.)

  5. For each volume or weight measurement, multiply by your scaling factor three times. In this case, the weight moves from 20000 lbs to 21110 lbs. (Another way to say this is that you are multiplying by the cube of your scaling factor.)

Finally, some observations, caveats, and jargon:

  • Jargon: A very terse way to describe this is to say, "We are determining a linear scaling factor. We are applying it directly to linear measurements, applying its square to the area measurements, and applying its cube to the volume measurements."

  • Caveat: When determining that scaling factor in step one, you must use values from the same column, and the column must be a length measurement column. If you start by comparing weight to weight or area to area, this process would have to be modified. For the sake of simplicity, I would just always use overall length to overall length.

  • Observation: Volume/weight measurements will change a lot, more than you might expect. Same with area measurements, to a lesser degree. Length measurement least of all.

  • Observation: The difference between 55 ft and 56 feet is pretty small, honestly. Using this process seems like overkill to me. But that's a judgment call. It's more useful at, say, 75 ft overall length (which is right between two rows) or 150 feet (which is off the chart entirely.)

  • \$\begingroup\$ Thank you! I appreciate it. It's always good to have a second explanation for things like this for me. It makes understanding it a lot easier lol. \$\endgroup\$ Commented Jul 3, 2023 at 22:25

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