Measure yourself first, then compare to the pattern's size chart

Sizing up a sewing pattern means choosing a larger size than you normally wear in ready-made clothes. You do this by measuring your actual body, finding those measurements on the pattern's size chart, and selecting the pattern size that matches — not your usual store size. A pattern marked "Size 12" is not the same as a dress you buy off a rack marked size 12. Pattern companies use different measurement standards than clothing manufacturers, so you have to check the numbers themselves.

The pattern envelope includes a printed size chart on the back. This chart lists bust, waist, hip, and sometimes shoulder width and length for each available size. You measure your own body in the same places, then find the row on the chart where your measurements fit best. If your bust is 38 inches, you look for the pattern size whose bust measurement is closest to 38 inches — even if that size number seems too large.

Most sewers size up because they want wearing ease — the extra room that lets you move, sit, and breathe comfortably in a finished garment. A pattern sized exactly to your measurements will fit tight. You typically add 2 to 4 inches of ease for a close fit, 4 to 6 inches for a comfortable everyday fit, and 6 inches or more for a loose, flowing garment. The pattern already includes some ease built in, so you are choosing a size that gives you the total ease you want.

Key Takeaways

  • Measure your bust, waist, and hips in the same way the pattern size chart does — straight across the fullest part, with the tape measure snug but not tight.
  • Find the pattern size whose measurements match yours, not the size number you wear in stores, because pattern companies use different standards.
  • Most patterns include 2 to 4 inches of ease already built in, so choose a size that gives you the total ease you want when worn.
  • If your measurements fall between two sizes, choose based on the measurement that matters most for that garment — bust for fitted tops, hips for skirts and pants.

How to take accurate body measurements

Wear a thin, fitted shirt and pants without a belt. Stand in front of a mirror with your arms at your sides and your posture relaxed — the way you actually stand, not pulled up straight. Have someone else measure you if possible, because measuring yourself accurately is difficult. Use a soft measuring tape, not a ruler or a piece of string you measure later.

Measure your bust by running the tape across the fullest part of your chest, keeping it level and parallel to the ground. The tape should be snug enough that it does not slip, but not so tight that it compresses the fabric or your skin. Write down the number where the tape overlaps. Measure your natural waist — the narrowest part of your torso, usually an inch or two above your belly button — the same way. Measure your hips at the fullest point, usually 7 to 9 inches below your waist. For pants and skirts, also measure your inseam: stand barefoot with your legs slightly apart, and measure from your inner thigh down to your ankle bone.

Take each measurement twice to catch mistakes. If the two numbers differ, measure a third time and use the middle number. Write all measurements down before you forget them.

Reading the pattern size chart and choosing your size

Open the pattern envelope and look at the back. You will see a printed table with size numbers across the top and body measurements down the left side. Each column under a size number shows what that pattern size measures when finished and laid flat — before you put it on. The chart usually includes bust, waist, hip, and sometimes shoulder width, back length, or sleeve length.

Find the row for bust measurement and look across until you find the size whose bust measurement is closest to yours. Then check the waist and hip rows for that same size. If all three of your measurements fall within that size's column, you have found your size. If your measurements span two sizes — for example, your bust matches Size 10 but your hips match Size 12 — choose based on which measurement matters most for the garment. For a fitted blouse, go with bust. For a skirt or pants, go with hips. You can always adjust the side seams by a small amount during sewing.

Some patterns list finished measurements and some list ease included. Read the fine print on the chart. If it says "finished measurements" or "garment measurements," those are the numbers the pattern will produce when you sew it. If it says "ease included," the pattern already has extra room built in. Either way, you are looking for the size whose finished measurement matches the measurement you want to wear, not your bare body measurement.

Grading between sizes when you are in between

If your bust is 36 inches and Size 8 measures 35 inches while Size 10 measures 37 inches, you are between sizes. You can grade the pattern — make it larger or smaller in specific places — to fit you better than choosing one size would.

The simplest method is to blend between sizes. Trace or photocopy the Size 8 pattern pieces. Then trace the Size 10 pieces on the same paper, but offset them slightly so you can see both outlines. Draw a new line that splits the difference between the two — roughly halfway between the Size 8 and Size 10 lines. This works best for the side seams and armholes. For length, you can usually just pick one size; length differences between sizes are usually small enough that you can adjust with a hem.

Another option is to grade up one full size and then take in the seams slightly. If you choose Size 10 when you measure closer to Size 9, you can sew the side seams 1/4 inch deeper than the pattern shows, which removes 1/2 inch from the total width. This is easier than blending if you are only slightly between sizes.

Adjusting length separately from width

Pattern sizes change width and length together, but your body might need a different size in each direction. A common situation is needing a Size 10 in the bust but Size 8 in the length. You can adjust these independently.

For length, measure from your shoulder bone down to where you want the garment to end — the hip for a shirt, the knee for a skirt, the ankle for pants. Compare this to the length measurement on the pattern size chart. If you are 2 inches shorter than the pattern assumes, you will need to shorten the pattern pieces by 2 inches. Most patterns have a marked lengthen/shorten line printed on the pieces — usually a double line with arrows. Cut along this line, remove the amount you need to shorten, or add a strip of pattern paper if you need to lengthen. Do this before you cut your fabric.

Width adjustments are separate. Once you have chosen your size based on bust, waist, and hip, you can still adjust the side seams during sewing. Sewing 1/4 inch deeper on each side seam removes 1/2 inch from the total width. This is easier than adjusting the pattern itself.

Common sizing mistakes and how to avoid them

The biggest mistake is using your ready-made clothing size instead of measuring yourself. A size 12 dress from a department store is not the same as a Size 12 pattern. Pattern companies use different measurement standards, and ready-made clothes vary widely by brand. Always measure your body and check the pattern size chart.

Another common error is forgetting to account for ease. If you choose a pattern size that matches your bare measurements exactly, the finished garment will be uncomfortably tight. You need to choose a size that is 2 to 6 inches larger than your body, depending on the style. A fitted dress needs less ease than a loose shirt.

Some sewers measure themselves while wearing a thick sweater or while pulling the tape measure too tight. Measure in a thin shirt and keep the tape snug but not compressing. Measure the same way twice to catch mistakes. If you are between sizes and unsure which to choose, pick the larger size — it is easier to take in seams than to let them out, and you can always adjust during fitting.

Frequently Asked Questions

What if I am between two pattern sizes?

Choose based on the measurement that matters most for that garment. For a fitted top, go with bust. For pants or a skirt, go with hips. You can blend between the two sizes on the pattern pieces, or choose the larger size and take in the seams slightly during sewing.

Do I need to add extra room to the pattern size I choose?

No. The pattern size chart shows finished measurements that already include ease. When you choose a size based on the chart, the finished garment will have the right amount of room built in. You do not add extra beyond what the pattern includes.

Can I use my ready-made clothing size to pick a pattern size?

No. Ready-made sizes vary by brand and manufacturer, but pattern companies use consistent measurement standards. Always measure your body and match it to the pattern size chart instead of guessing based on store sizes.

What if the pattern does not have a size chart?

Older patterns and some indie patterns do not include a printed chart. Look for finished measurements listed in the pattern instructions or on the envelope. If none are listed, measure a finished garment you own that fits well and compare those measurements to the pattern pieces laid flat.

Should I size up if I want a loose, flowing garment?

Choose the size based on your actual measurements and the ease already in the pattern. If you want extra looseness beyond what the pattern includes, you can grade up one full size, or you can add width to the pattern pieces by drawing new seam lines further out from the original ones.