Sizing in womenswear is less consistent than in any other clothing category — across makers, across countries and across decades. Measurements are the only reliable information, and even they need one qualifier.
Why the stated size is not enough
Makers differ, countries differ, and the same label has meant different bodies in different years. An altered garment does not match its own label at all.
The measurements that decide fit
Taken flat, garment laid out, not pulled:
Tops, kurtas and dresses — bust armpit to armpit (doubled), waist flat, hip flat, shoulder to shoulder, full length from the shoulder, sleeve length. Skirts and trousers — waist flat, hip flat, length, inseam, leg opening. Blouses for ethnic sets — bust, shoulder, sleeve, length.
The qualifier that matters most
"Is there stretch, and is that the relaxed measurement?"
A garment measured while being pulled is a garment that will not fit the way the numbers suggest. Ask for the relaxed figure. Questions to ask.
Seam allowance is a sizing fact
For occasion and ethnic wear especially, how much margin is left in the seams decides whether a piece can be made to fit you. Ask, because an alteration is often cheaper than the right size is rare.
Compare against your own
Measure something you own and like, flat, and keep the numbers. It is faster than any chart and it is actually about you.
What protection covers
Measurements materially wrong, a different garment, an alteration not mentioned: seven days from delivery. A fit you hoped for, against accurate numbers, is not.
Questions people ask
Is a modelled photograph useful?
It tells you about the model. Ask for flat measurements as well.
Can most pieces be altered?
Taken in, usually. Let out, only with allowance.
What about sarees?
Length, width and blouse piece — the saree guide.