How to Choose the Right Sewing Pattern Size

One of the loveliest things about sewing your own clothes is that you aren’t limited to whatever happens to fit you on a store rack. You get to choose the fabric, the details, the length, the fit, and ultimately create something that feels like you.

But before you can begin sewing, you have to answer a surprisingly tricky question:

What size should I make?

If the number on a sewing pattern looks different from the size you normally buy in a store, don’t worry. Sewing pattern sizes and ready-to-wear clothing sizes are completely different systems, and the number itself doesn’t mean anything about your body.

Your measurements are simply information. They help you choose the best starting point for creating a garment that feels good when you wear it.

In this guide, you’ll learn how to choose a sewing pattern size using your body measurements, the pattern’s size chart, the intended wearing ease, and your preferred fit.

Sewing Pattern Sizes Are Different from Store-Bought Sizes

The first, and perhaps most important, rule of choosing a sewing pattern size is to forget the size you usually buy at the store.

Ready-to-wear sizing varies enormously between brands. You might wear one size at one store and an entirely different size somewhere else. Sewing pattern companies also develop their own size charts using their own blocks, proportions, and fit standards.

That means your usual clothing size may have very little connection to your sewing pattern size.

Always choose your pattern size using your current body measurements and the size chart included with that specific pattern.

If the size number is higher or lower than you expected, it doesn’t mean your body has changed or that anything is wrong. It simply means you are using a different sizing system.

Begin with Accurate Body Measurements

Before choosing a size, learn how to take accurate body measurements for sewing.

Even if you measured yourself recently, it’s worth checking again. Bodies naturally change over time, and even small differences can affect which size will provide the best starting point.

Depending on the garment, you may need measurements such as:

• Upper bust
• Full bust
• Natural waist
• Full hip
• Height
• Trunk length

Wear close-fitting clothing or undergarments, keep the measuring tape level, and avoid pulling it too tightly.

Find the Pattern’s Body Measurement Chart

Most sewing patterns include two different sets of measurements:

1. Body measurements
2. Design ease

Begin with the body measurement chart.

Body measurements represent the measurements the pattern was designed to fit. Compare your measurements with the chart and note the size that corresponds most closely with each part of your body.

For example, your measurements might place your bust in one size, your waist in another, and your hips in a third.

This is completely normal.

Very few people match every measurement in a single size. One of the advantages of sewing is that you can adjust the pattern to fit your unique combination of proportions instead of expecting your body to fit neatly into one column on a chart.

How to Choose a Sewing Pattern Size Using Your Measurements?

The most important measurement depends on the type of garment you are making.

For Tops, Dresses, and Bodices

For a fitted top or dress, begin with the measurement that determines how the garment fits through the shoulders and upper body. This is typically the upper bust measurement.

If the pattern includes different cup sizes, use the pattern’s instructions to select your base size and cup option. This commonly involves comparing your upper-bust and full-bust measurements.

Choosing from the upper bust can often produce a better fit through the shoulders, neckline, and upper chest than choosing a larger size based only on the full bust. You can then select the appropriate cup size or make a bust adjustment if necessary.

Always follow the instructions provided with the pattern, since cup-sizing methods can vary between pattern companies.

For Skirts and Pants

For skirts, pants, and shorts, begin with the hip measurement unless the pattern instructions say otherwise.

The garment must have enough room to fit over the fullest part of your lower body. The waist is generally easier to adjust afterward.

For a very full or gathered skirt, the waist may be the most important measurement because the design already includes generous room through the hips.

For Children’s Patterns

For children’s tops and dresses, the chest measurement is usually the best place to begin. For pants, shorts, and fitted skirts, we generally use the hip measurement.

You should also compare the child’s height with the height listed in the size chart. Children often need the width of one size and the length of another.

Choose the size that fits the child’s current measurements rather than sizing up automatically for growth. If you would like the garment to last longer, look for adjustments that add growing room without making the entire garment oversized such as extra hem allowance, adjustable straps, elastic waists, or adjustable cuffs.

What If You Fall Between Sizes?

If one of your measurements falls between two sizes, don’t immediately assume you should choose the larger one.

First, consider:

• The style of the garment
• The amount of stretch in your fabric
• How much ease is included
• How you prefer your clothing to fit
• Which part of the garment is most fitted

If you prefer a little more room or are using a fabric with less stretch than recommended, the larger size may feel more comfortable.

If the garment is intentionally loose, the fabric is very stretchy, or you prefer a closer fit, the smaller size may be appropriate.

The intended design ease can help you make this decision.

Understanding Design Ease

In Boo & Lu patterns, you’ll find the intended design ease listed in the pattern tutorial. This tells you how much larger or smaller the garment is designed to be compared with the corresponding body measurement.

Ease affects both the comfort and the overall silhouette of a garment.

Positive ease means the finished garment is larger than the body. This provides room for movement and may also create a relaxed, loose, or drapey silhouette.

Negative ease means the finished garment is smaller than the body. This is commonly used in knit garments, where the fabric stretches to fit the body and creates a closer silhouette.

For example, if a pattern includes 2 inches of positive ease at the bust, the garment is designed to measure approximately 2 inches larger than the corresponding body measurement. If it includes 2 inches of negative ease, it is designed to measure approximately 2 inches smaller.

Consider the listed design ease alongside your preferred fit. Two patterns drafted for the same body measurements may fit very differently: one might be designed to skim the body, while another may have a loose, flowing shape.

Your Boo & Lu tutorial also includes a finished measurement chart showing the garment’s final lengths in both inches and centimeters. Use these measurements to evaluate details such as bodice, skirt, inseam, or overall garment length and determine whether you would like to lengthen or shorten the pattern.

Together, the size chart, listed design ease, and finished lengths give you a clearer picture of how the completed garment is intended to fit and feel.

Think About How You Want the Garment to Feel

A size chart can give you a starting point, but it cannot tell you how you personally like to wear your clothes.

Before choosing your size, think about garments you already love.

Do you prefer your tops to skim your body or fit closely? Do you like a defined waist, or do you feel more comfortable with extra room? Do you prefer fitted sleeves or a more relaxed shape?

There isn’t one universally “correct” amount of ease. The goal is to preserve the designer’s intended silhouette while creating a garment you will genuinely enjoy wearing.

This is where sewing becomes more than following a chart. You are making thoughtful choices about what feels most like you.

You Don’t Have to Choose Only One Size

If your bust, waist, and hip measurements fall into different sizes, you can blend between sizes.

Blending, or grading, between sizes means drawing a smooth line from one size to another. For example, you might use one size through the bust, transition to another at the waist, and use a third through the hips.

When blending sizes:

• Make gradual transitions rather than sharp angles.
• Blend both the front and back pattern pieces where needed.
• Make the same adjustment to adjoining pieces.
• Check that seams that will be sewn together remain the same length.
• Preserve important landmarks such as notches, waistlines, and lengthen-or-shorten lines.

Choosing different sizes for different parts of the pattern is not a sign that you selected the wrong size. It is one of the ways you personalize the pattern to your proportions.

Don’t Use the Largest Measurement for Everything

It can be tempting to find your largest measurement on the size chart and make that size for the entire garment. However, this can create new fit problems.

For example, choosing a bodice size based only on the full bust may make the shoulders and neckline too wide. Choosing pants entirely from the waist measurement could result in too much room through the hips and legs.

Instead, choose the base size using the measurement that controls the garment’s most difficult-to-adjust area. Then blend sizes or make a targeted adjustment where you need additional or reduced room.

Consider Your Fabric Before Making a Final Decision

Fabric choice can noticeably change how a garment fits.

Pay attention to the fabric type and stretch percentage recommended in the pattern. A pattern designed for knit fabric will not fit as intended if it is made from a non-stretch woven fabric.

Even fabrics within the same category can behave differently.

A stable cotton jersey may feel more fitted than a soft rayon spandex. A crisp cotton lawn may create more structure than a drapey rayon woven. A heavy fabric may also feel more restrictive than a lightweight version of the same garment.

If your fabric has less stretch or drape than the recommended fabric, you may need additional ease. If it is especially stretchy or fluid, you may prefer less.

Make a Test Garment When Fit Matters

When making a fitted garment or using a pattern company for the first time, consider sewing a test version before cutting into special fabric.

A test garment allows you to check:

• Shoulder width
• Bust fit
• Waist placement
• Hip room
• Bodice and sleeve length
• Rise and crotch fit
• Overall ease
• Your comfort while moving, sitting, and reaching

Your test version doesn’t have to be perfect or beautiful. It simply gives you useful information before you invest more time and fabric in the final garment.

For knit patterns, use a test fabric with a similar stretch and recovery to your final fabric. For woven patterns, choose something with a similar weight and drape.

Common Sewing Pattern Sizing Mistakes

Before cutting your pattern, watch for these common mistakes:

Choosing Your Ready-to-Wear Size

Store-bought sizes are not the same as sewing pattern sizes. Always begin with the pattern’s measurement chart.

Using Outdated Measurements

Use your current measurements rather than the measurements you remember or hope are still accurate.

Pulling the Measuring Tape Too Tightly

The tape should rest against your body without compressing it.

Ignoring Design Ease Measurements

Body measurements help you choose a starting size. Finished design ease help you understand how that size is intended to fit.

Automatically Sizing Up

A larger size does not always create a more comfortable garment. It may also change the shoulder width, neckline, armhole, rise, or overall proportions.

Ignoring Fabric Requirements

The right size cannot compensate for fabric that does not have the stretch, recovery, weight, or drape required by the pattern.

Expecting One Size to Match Every Measurement

Most bodies span more than one size. Blending between sizes is a normal part of fitting a sewing pattern.

Your Pattern Size Is Only a Starting Point

Choosing a sewing pattern size isn’t about finding a number that perfectly defines your body. It’s about finding the best place to begin.

Start with accurate measurements. Use the pattern’s own size chart. Look at the finished garment measurements, consider the fabric, and think about how you want the finished garment to feel.

Then give yourself permission to blend sizes, adjust proportions, and make the pattern your own.

Because the real magic of sewing isn’t making your body fit a standard size.

It’s creating something that fits your body, your life, and your sense of style so you can sew something that feels like you.