How to measure yourself for maternity clothes
Almost every disappointing parcel comes down to the same thing: a size guessed from a label instead of read from a tape measure. Four measurements, taken once, will do more for what arrives at your door than any amount of scrolling. Here’s how to take them, and how to read them.
Why the label can’t help you
There is no shared sizing standard in clothing. Every brand drafts to its own block and publishes its own chart, which is why the same body is genuinely a 12 at one label and a 16 at another. Your dress size isn’t a property of your body — it’s a property of whichever shop you happened to buy from last.
Your measurements, on the other hand, are yours. Take them once, keep them on your phone, and compare them against each brand’s own published chart. It’s a two-minute habit that ends the returns cycle, and it’s the same method any good fitter would use.
The four that actually matter
You’ll see charts asking for eight or ten measurements. For maternity, four of them carry almost all the weight.
- Hip and seat — the fullest part, usually around 20cm below your natural waist. This is the important one. In a true-to-size maternity garment, the panel handles the bump, so your hip is what decides whether the rest of the piece fits. If you only take one measurement, take this.
- Underbust — directly beneath the bust, snug but not tight. This is the number that decides every empire line, every band, every bra, and it’s the one most likely to have changed without your noticing.
- Natural waist — the narrowest point of your torso, which while pregnant sits higher than you expect. Useful for wrap and tie styles, which fasten there.
- Height and inside leg — for trouser and dress length, the two things nobody measures and everybody complains about.
Taking them properly
The technique is simple and the mistakes are consistent, so it’s worth reading this bit even if you’ve done it before.
- Wear thin clothes or none. A jumper adds several centimetres and ruins the whole exercise.
- Keep the tape level. Check the back in a mirror — a tape that slopes downwards behind you is the most common single error, and it always reads too large.
- Snug, not tight. The tape should sit against you without compressing. If it leaves a mark, it’s too tight.
- Breathe out, then stop. Don’t hold your stomach in, and don’t hold your breath.
- Write them down immediately, in centimetres, with the date. You will not remember them.
Don’t bother measuring your bump
This surprises people, but bump measurement is the least useful number you can take. It changes week to week, and maternity garments are specifically drafted to expand over it — that’s the entire purpose of a panel, ruching or an empire seam. Measure the parts that stay comparatively stable and let the garment do its job over the part that doesn’t.
Reading a size chart without being misled
Find the brand’s own chart — not a generic conversion table, not a third-party one. Then match your largest relevant measurement to the chart, not your average. A garment fits at its tightest point, so averaging two measurements reliably produces something that pulls somewhere.
If you fall between sizes, the garment’s construction decides. Anything fitted through the ribcage: take the larger. Over-bump trousers and jeans: the smaller usually gives a cleaner seat, since the panel does the expanding. Anything wrap, tie or A-line: either, because you’ll set the fit yourself. Our guide to whether to size up goes through this properly.
Re-measure, but not obsessively
Once a trimester is enough. Your hip, seat and underbust shift slowly and predictably; the bump changes fast and matters least. Then measure again a few months after birth, because several numbers will have settled somewhere new — a ribcage that widened often stays a little wider, and feet frequently go up a half size and stay there.
And treat all of it as a suggestion
A size chart has never met your body. It describes an average that a brand drafted to, and it can’t know how you’re carrying, how a fabric behaves on you, or what you find comfortable. Measurements will get you far closer than guessing — but they’re a well-informed recommendation, never a guarantee, which is why buying from somewhere with a returns policy you can actually use still matters.
Common questions
Which measurement matters most for maternity clothes?
The fullest part of your hip and seat. In a true-to-size maternity garment the panel handles the bump, so the hip measurement is what decides whether the rest of the piece fits. It is a far more reliable number than your dress size.
Should I measure over my bump?
For most garments, no. Bump measurement changes week to week and maternity pieces are drafted to expand over it anyway. Measure the parts that stay comparatively stable — underbust, waist at its narrowest, hip and seat, and your height for length.
How often should I re-measure while pregnant?
Once a trimester is plenty. Your hip, seat and underbust shift slowly; the bump changes fast but matters least. Re-measure again a few months after birth, when several measurements will have settled somewhere new.
Why do my measurements give a different size at every brand?
Because there is no shared standard. Every brand drafts to its own block and publishes its own chart, so the same body can be three different sizes across three labels. That is exactly why the measurements beat the size label — use the numbers against each brand’s own chart rather than assuming your size travels.
What if I fall between two sizes?
Go by the garment’s tightest point. For anything fitted through the ribcage, take the larger size. For over-bump trousers and jeans, the smaller size usually gives a cleaner seat, because the panel does the expanding. For anything wrap, tie or A-line, either will work.