The pot has a diameter of 30 cm at the top, it is narrower at the bottom and the height of the pot is 26 cm. I also bought the Ecopots Amsterdam 30 cm saucer.

30 cm measured from the outside is correct

Hello
The outer diameter at the top edge of the pot is 30 cm. The inside diameter is 28 cm.
I have Eco-Pots in various sizes in my flat and don't use coasters at all (only castors). The pots have a closed base or a rubber spigot that seals them. However, if you do want to buy coasters, the matching ones are usually shown with the product

Hello,

I measured and it's more like 27 cm in diameter from the inside edge to the other inside edge.
Take a saucer with a good surface because in my case, the water has trouble draining and stagnates under the pot.