Fullest Bust: Measure around the fullest part of your bust using a soft tape measure without an padded bra.(Band size)
Under Bust: Measure under your breasts (snug, but not tight) and round up to the next even number.
Bust size- Band size = Cup size: Subtract your band size from your bust size to find your cup size.

Hips: Measure around the fullest part of your hips underneath your baby bump.

Sleeve Length: Using a soft tape measure, measure from the center of your armpit down your arm towards your wrist.

The size guide is for reference only. Different measurement methods will have 2-4cm error, which is a reasonable range.