Here is the issue, in one country, I have my character moving from one side (east) to a city in the southwest. I needed to figure out the distance for so that I know how long it would take them to travel. (Horses part of the way, carriage part of the way to the halfway point) However, when I added a guide for measuring, using an idea that I thought made sense with the earth as a reference, I don't think it went the way I anticipated. So, I did the math; compared to earth my planet seems rather weirdly sized. Obviously, changing a flat plane to a sphere is kinda weird, and I don't know the math for such things.

When it comes to earth size, Google says: equatorial circumference of Earth is about 24,901 miles (40,075 km). However, from pole-to-pole — the meridional circumference — Earth is only 24,860 miles (40,008 km) around.

So, I have 1 inch = 2800 miles. My map is 18x9 Which means its 50,400 miles across, and 25,200 top to bottom.

I haven't a clue how big this would make the planet, and if anyone can help with that I'd be grateful. (yes, I am aware if I take these exact measurements I'd get an oblong planet. Which is why I need the help...)

I have a feeling, that my guide is like WAY off, and I need to find a better number of miles per inch. Though, If that is the case, my continents are going to need resizing.....

I don't know. Maybe there is an easier way to go about things? If there is, please let me know because I've been circling this drain awhile.