Standard US women's dress size chart (bust-waist-hip in inches):
0 = 32-24-35, 2 = 33-25-36, 4 = 34-26-37, 6 = 35-27-38, 8 = 36-28-39.
10 = 37-29-40, 12 = 38.5-30.5-41.5, 14 = 40-32-43, 16 = 41.5-33.5-44.5.
18W = 43-35-46, 20W = 45-37-48, 22W = 47-39-50, 24W = 49-41-52.
These are 'standard' but every brand drifts from them. Always cross-check the brand's specific chart.