What size round is best for an engagement ring?

1 carat (about 6.5 mm) is the most searched size. 1.5 and 2 carat rounds are the next steps up if you want more presence.

Guides

Round diamond size chart

Round brilliants are the shape these millimeter charts are built for.

Approximate diameters by carat

Approximate diameters: 0.50 ct ≈ 5.1 mm, 1.00 ct ≈ 6.4 mm, 1.50 ct ≈ 7.4 mm, 2.00 ct ≈ 8.1 mm, 2.50 ct ≈ 8.7 mm, 3.00 ct ≈ 9.3 mm.

Round diamond size chart with carat weights and diameters — Round diamond size chart — diameter in mm is the fair compare.

1 carat round diamond next to a coin for scale — 1.00 ct round benchmark: about 6.4 mm across.

Cut changes face-up size

An Excellent cut round uses that weight to make diameter. A thick, deep round hides carats in depth and looks smaller than the chart. Read the measurements line on the certificate before you compare prices.

Carat Mate lists certified loose diamonds for shoppers in the United States, Canada, the UAE, London, and Australia. Prices are in USD everywhere. We ship to the United States, Canada, the UAE, London, and Australia.

Round diamond cut proportions affecting sparkle and apparent size — A poorly cut round can look smaller and darker at the same carat.

Questions

What size round is best for an engagement ring?: 1 carat (about 6.5 mm) is the most searched size. 1.5 and 2 carat rounds are the next steps up if you want more presence.