What You'll Find on a Sewing Pattern Envelope

A sewing pattern envelope holds three things: the front cover with a photo of the finished garment, the back with sizing and fabric requirements, and the tissue-paper pattern pieces inside. The front shows you what you are making and which sizes are included in that one envelope—usually sizes 6 through 18, or XS through XL. The back lists how much fabric you need for each size, what notions (buttons, zippers, thread) to buy, and finished garment measurements so you can pick the right size for your body.

Inside the envelope are several sheets of thin tissue paper printed with pattern pieces, a guide sheet with step-by-step sewing instructions, and sometimes a pattern layout diagram. The tissue pieces are the actual templates you will cut from your fabric. Each piece is labeled with a number or letter, a name (like "Front Bodice" or "Sleeve"), and grain line markings that tell you which direction to lay the piece on your fabric.

Key Takeaways

  • The back of the envelope tells you how much fabric to buy and what size to cut based on your measurements, not your clothing size.
  • Each tissue pattern piece shows a grain line (usually a long arrow), seam allowance markings, and notches that match pieces together during sewing.
  • The guide sheet inside lists every step in order, from cutting to sewing to finishing, with diagrams showing how pieces fit together.
  • Laying out pattern pieces correctly on your fabric—following the grain line and layout diagram—prevents your finished garment from twisting or pulling.
  • Marking notches, dots, and other symbols on your fabric before removing the pattern pieces keeps you from losing track of where seams meet.

Choosing Your Size from Measurements, Not Labels

Sewing pattern sizes do not match store clothing sizes. A pattern size 12 is not the same as a dress size 12 from a department store. Instead, you measure yourself and compare those measurements to the finished garment measurements printed on the back of the envelope.

Measure your bust, waist, and hip at the fullest points while wearing a bra but no bulky layers. Write down the numbers. Then look at the back of the envelope where it says "Finished Bust," "Finished Waist," and "Finished Hip" for each size. Choose the size whose finished measurements match where you want the garment to fit. If you are between sizes, pick the one closer to your bust measurement—you can adjust waist and hip seams more easily than bust seams.

The envelope also shows the finished length of the garment. If you are much taller or shorter than average, note this now so you can plan to lengthen or shorten the pattern pieces before cutting.

Understanding Pattern Piece Markings and Symbols

Each tissue pattern piece is covered with printed lines and symbols. The grain line is a long arrow or line with arrows at both ends—this shows which direction the piece must lie on your fabric. Grain lines run parallel to the selvage (the finished edge of the fabric bolt) and prevent your finished garment from twisting or sagging. Always lay the grain line exactly as shown, or your garment will not hang straight.

Notches are small triangles or diamonds cut into the seam allowance (the blank space around the edge of the pattern piece). Notches match one piece to another—a notch on the armhole of the front bodice lines up with a notch on the sleeve cap so you know exactly where to sew them together. Dots and circles mark pivot points where you change sewing direction, or where darts (stitched folds that shape the fabric) begin and end.

The seam allowance is the blank space between the cutting line (the outer edge) and the stitching line (usually marked with a dashed line inside). Most patterns include a 5/8-inch seam allowance. You cut on the outer line and sew on the inner line. Some pattern pieces say "Cut on fold"—this means you fold your fabric and lay that edge of the pattern on the fold so the piece comes out twice as wide when you unfold it.

Reading the Pattern Layout Diagram

The guide sheet inside the envelope shows a layout diagram—a bird's-eye view of how to arrange all the pattern pieces on your fabric before cutting. The diagram looks like a rectangle (your fabric) with small shapes (the pattern pieces) arranged on it. Different layouts are shown for different fabric widths (usually 45 inches or 60 inches) and for different sizes.

Find the layout for your size and your fabric width. The diagram shows which direction each piece faces and whether pieces overlap or touch. Some pieces are laid with the grain line running lengthwise down the fabric; others run across. Follow the layout exactly—it is designed to use the least fabric and to position pieces so grain lines are correct and pattern repeats (if your fabric has stripes or a print) line up properly.

If your fabric has a nap (a pile or sheen that looks different depending on which direction you brush it, like corduroy or velvet), use the "with nap" layout if one is provided. This layout arranges all pieces in the same direction so the nap runs the same way on every piece of your finished garment.

Following the Step-by-Step Sewing Instructions

The guide sheet lists every sewing step in order, numbered and illustrated with small diagrams. Read through the entire list before you start sewing so you know what comes next. The instructions tell you which pieces to sew together first, which seams to press open or to one side, and when to attach notions like zippers or buttons.

Each step includes a small drawing showing how two pieces fit together and which edges to sew. The drawing shows seam allowances as a thin line and the stitching line as a dashed line. If the instruction says "Sew front to back at shoulder seams," the diagram shows you exactly which edges meet and in which direction to feed the fabric under the presser foot.

Some instructions use abbreviations: "RS" means right side (the pretty side of the fabric), "WS" means wrong side (the back), and "RST" means right sides together (the pretty sides facing each other, which is how you usually sew seams). If you see "Press seam open," use an iron to flatten the seam allowances on both sides of the stitching line. If it says "Press seam to one side," fold both seam allowances toward one piece and press them flat.

Marking Your Fabric Before Cutting

Before you remove the pattern pieces from your fabric, mark all the notches, dots, and other symbols onto the fabric itself. Use a fabric pencil, chalk, or tailor's tacks (small hand stitches in contrasting thread). Notches can be cut into the seam allowance with scissors, but dots and darts must be marked with pencil or thread so you can see them after the pattern is removed.

Mark both layers of fabric if you are cutting through two layers at once. This takes a few extra minutes but prevents you from sewing seams in the wrong place later. If you forget to mark a dot or notch, you can always look back at the pattern piece to see where it was, but it is faster to mark everything while the pattern is still in place.

For darts, mark both the point (where the dart ends) and the two legs (the lines you will sew). You can do this by poking a pin through the pattern and fabric, then marking where the pin came through on the wrong side of the fabric. Or fold the pattern piece and mark with pencil on the fabric underneath.

Common Mistakes to Avoid When Reading Patterns

The most common mistake is choosing the wrong size by comparing pattern sizes to store clothing sizes instead of measuring and comparing finished garment measurements. This leads to a garment that is too big or too small. Measure yourself once and refer to the back of the envelope every time.

Another frequent error is ignoring the grain line. If you lay a pattern piece at an angle instead of parallel to the selvage, the finished garment will twist and pull. The grain line is printed on every piece for a reason—follow it exactly.

Many beginners also forget to mark notches and dots before removing the pattern, then realize mid-sewing that they do not know where seams should meet. Spend two minutes marking everything while the pattern is in place. It saves confusion later.

Finally, do not assume the pattern is wrong if something looks odd. Patterns are tested by sewers of different sizes and skill levels. If an instruction seems strange, read it again carefully and look at the diagram. Usually the instruction is correct and makes sense once you understand what it is asking you to do.

Frequently Asked Questions

What does "cut on fold" mean?

It means you fold your fabric in half and lay that edge of the pattern piece exactly on the fold. When you cut around the pattern and unfold the fabric, that piece comes out twice as wide. This is used for pieces like the back of a shirt that need to be one continuous piece rather than two pieces sewn together.

Can I use a pattern in a different size than what I measured?

Yes, if you understand what will change. If you pick a size larger than your measurements, the garment will be looser. If you pick a size smaller, it will be tighter. You will need to buy the amount of fabric listed for the size you chose, not your measured size, so check the back of the envelope before you shop.

What if my fabric is a different width than the pattern layout shows?

Most patterns show layouts for 45-inch and 60-inch fabric widths. If your fabric is a different width, you may need more or less yardage. Lay out your pattern pieces on your actual fabric before cutting to see if they fit. If they do not, you may need to buy extra fabric or find a different layout online for your width.

Do I have to follow the pattern exactly, or can I change things?

You can change things once you understand how the pattern works. Beginners should follow the pattern as written the first time so they learn how pieces fit together. After you have made a garment, you will understand where you can add length, change necklines, or adjust fit for future projects.

What if I lose a pattern piece?

You can trace the missing piece from another copy of the pattern if you have one, or contact the pattern company to see if they sell replacement pieces. Some companies offer digital downloads of patterns so you can print a new copy. Check the envelope or the company website for their policy.