Why this site exists
Every pattern company publishes a size chart, and every one of them stops there. You are left holding three different answers — a 16 at the bust, a 12 at the waist, a 14 at the hip — and no instruction on what to do about it. The advice that fills the gap is either a blog post about somebody else's body or a calculator that only knows one brand's numbers.
We keep the published body-measurement charts for eight brands side by side and read your measurements against all of them. That is the whole idea. A Big 4 size 16 is not a Cashmerette 16 and neither is a Merchant & Mills 16, so the number on the envelope is meaningless until it is tied to the chart it came from.
We do not sell patterns, take commission on them, or have any reason to steer you toward a brand. The charts are reproduced as published, each one linked back to its source, and every assumption behind the arithmetic is written on the page rather than hidden behind it.
Sew a muslin. No calculator replaces a test garment in cheap fabric — this one just means your first muslin starts from a sensible place instead of a guess.