A couple days ago I found myself facing this problematic: I have a round dinning table of 140cm of diameter, and I was wondering which would be the right size for my new carpet, and whether it should be circular or square.
When choosing a carpet for your dining room, there are two main things you need to ask yourself:
Do you dine every day at the table?
or do you use it as a "showpiece"?
If you have a big room and have the space to throw a big big carpet, then fantastic! However, if your space is more limited it is important to consider comfort but also proportions.
If you opted for number 1, then you need to think about getting a big enough carpet that does not interfere whenever you need to pull the chairs out. For example, if your table size is 100x200cm, then I would recommend you add 75-100cm to each side of the table.
If your answer is number 2, then what really matters is that the size of the carpet is proportional to the size of the table + chairs. Adding 40-50cm per each side of the table would create a good ensemble.
Another tip when choosing the carpet for a dining area frequently used is to look for easy-to-clean materials and textiles. For example, materials such as rattan or bamboo are very trendy and also easy to maintain.