The side plate 18.2cm wide.

The saucer is 13.9cm wide.

The large cup is 6.9cm wide and 6.9cm high.

The smaller cup is 6.4cm high and 6cm wide, please note it is a lighter colour pink.

The smaller cup can sit on the saucer as well but moves around a little because it is not as wide at the bottom as the larger cup.

(ref.1)