How large is the planet of the Forgotten Realms?

Question

My answer to this question:

How far can a ship "see" in 5e?

prompted the question whether the Forgotten Realms are on a disc or a planet. It is a planet, as evident from the answer to this question:

Where does the Sun go at night?

However, I’m wondering what size this planet is. This information would be relevant to calculate sight ranges. Barring any contradictory information I would assume, similar to the size of earth, but my question is, if there is any official information to corroborate this or give a different size. Information for 5E is preferable, since the other question was also specifically about 5E, although I suppose that this probably has not changed between editions, so prior editions are valid if there is nothing specifically from 5E.

Answer 1

Toril, the planet of the Forgotten Reals setting, is a size E (earth sized) spherical body (4,000-10,000 miles or 6,400–16,000 km diameter).

Toril is the third planet from the sun inside Realmspace, which is a crystal sphere of size J (3,200,000,000 mi / 5,100,000,000 km diameter).

There are some good maps available from Wizards of the Coast, and an overview of Faerûn here : https://dnd.wizards.com/dungeons-and-dragons/what-is-dd/forgotten-realms but the people at the Forgotten Realms Wiki did a good job of collecting the references. You can check here : https://forgottenrealms.fandom.com/wiki/Toril for the entry on the planet, there are also links to the various continents. Obviously Faerûn is best devoloped, but the rest is not bad.

For Realmspace and the rest you can check here: https://forgottenrealms.fandom.com/wiki/Realmspace

You can also check out the Realms sidebar in the Concordance of Arcane Space and the Lorebook of the Void from the original Adventures in Space box if you know someone who has them. The Spelljammer: Piratesof Realmspace books and games also have some info or you can check out the speljammer wiki.

Alternatively the Forgotten Realms Campaign Setting and Forgotton Realms Player Guide from 4E were pretty good, although nothing beats the "Tour of the Realms " written by Jeff , Ed and Linda the original creators and campaigners in the 1993 2E version - don't have/know the 5E versions

Answer 2

Approximately Earth-sized

Gwyn's answer is correct, and I can't find any figure more precise for the exact size of Toril. All sources merely point to it being approximately Earth-sized.

The 3e Forgotten Realms Campaign Setting, p.231, contains a rare map of all Toril. The map projection being used is not stated, and the map's accuracy is uncertain, since it's specifically called "A Scholar's View of Abeir-Toril", several of the continents of which are simply called "Unknown Lands", and it is noted that "even the scholars of Candlekeep know only a little of what lies beyond the realms of Faerûn".

However, the map suggests that the continent of Faerûn is approximately one-fifth the circumference of the planet at its latitude. Given that we know the approximate width of Faerûn to be 3,500 miles (FRCS p.5), the planet of Toril is very approximately 17,500 miles in circumference at its latitude.

According to this website, the latitude of our Earth at 40 degrees North latitude is 30,600 km, or 19,014 miles. This is very close to our estimate and within a reasonable margin of error. The city of Waterdeep is at 45 degrees North latitude (FRCS p.79), so this latitude is approximately correct for Faerûn.

Unfortunately, the figures and methods used here are too imprecise to give an exact measurement. However, these estimates are consistent with the AD&D 2e Forgotten Realms Campaign Setting: A Grand Tour of the Realms p.4, which describes Abeir-Toril as "an Earth-sized planet", and the Spelljammer product Realmspace, which describes Toril as a Class E, meaning from 4,000 to 10,000 miles across, a category which includes our Earth at 7,917.5 miles diameter.