How to Copy a Garment to Create a Block Pattern in 30 Minutes

A favorite T-shirt or dress shirt can teach you more about fit than a stack of measurements. If it already sits well on the shoulders, feels right through the body, and has the length you reach for again and again, it can become the starting point for future garments.

This technique lets you copy a garment without taking it apart. You lay the garment flat on a corkboard, pin through the seams and key edges, then use those pin marks to draft a pattern. In about 20 to 30 minutes, you can create a simple block pattern that captures the shape of a garment you already love.

A well-fitting T-shirt makes a practical starting point for a block pattern.

Why copying a garment works so well

A block pattern is a base pattern. It is not meant to be fancy. It is the foundation you adjust, style, and reuse.

When you copy a garment you already wear, you begin with something proven. You know how it fits in real life. You know whether the sleeve feels comfortable, whether the neckline is too high or just right, and whether the body length works with your wardrobe.

This is especially useful for simple garments such as:

• T-shirts

• Dress shirt

• Jean

• Pants

• Jacket & Coats

  
  

A T-shirt or dress shirt are two of the easiest places to start because it has clear shapes and relatively few pieces. Most basic shirt patterns include a front, back, sleeve, and neckband or collar. Once copied, those pieces can become the basis for many other designs.

The goal is not to make a perfect production pattern on the first try. The goal is to capture the main shape quickly, then test and refine it.

What you need before you start

This method works best with simple tools. You do not need a drafting table or special equipment.

Gather these supplies:

• A corkboard large enough for the garment section you are copying

• Pattern paper or tracing paper

• Straight pins

• A pencil

• A clear ruler

• A French curve or curved ruler

• Tape

• Paper scissors

• Measuring tape

• The garment you want to copy

  
  

Choose a garment that is clean, pressed, and not stretched out. If the fabric twists badly or the seams no longer sit straight, pick a different piece. A worn-out shirt can give you a worn-out block.

For the first try, choose a T-shirt with a simple shape. Avoid dropped shoulders, twisted seams, heavy gathers, or complicated design lines until you understand the process.

Pins act like tiny landmarks that transfer the garment shape to paper.

How to pin the garment and capture the shape

Start by placing a sheet of paper on the corkboard. Pin the corners lightly so it does not shift. Lay the shirt flat on top of the paper.

Smooth the shirt gently with your hands. Do not stretch it. The fabric should lie naturally, the way it wants to sit. Find the center front, fold the shirt in half along the center front and copy the right side only.

Pin around the important areas:

• Center Front

• Shoulder seam

• Neckline

• Armhole

• Side seam

• Hem

  
  

Push each pin straight down through the garment, through the paper, and into the corkboard. You are not pinning to hold the shirt in place only. You are using the pins to leave a map.

Place pins closer together around curves. The neckline and armhole need more detail than a straight side seam. On straight sections, pins can be spaced farther apart.

Once the main points are pinned, carefully remove the garment while leaving the paper in place. If your pins stay in the corkboard, you will see the shape clearly. If you remove the pins as you go, mark each hole with a pencil first.

Connect the pin marks with smooth lines. Use a ruler for straight seams and a curved ruler for the neck and armhole. This is the moment when a dotted outline becomes a usable pattern.

Tip: Mark more than the outline. Add labels such as front, back, sleeve, fold line, grainline, and original hem. Future you will be grateful.

Turn the tracing into a usable block pattern

After you connect the pin marks, clean up the draft. Check that the lines look smooth and intentional. A copied garment often gives you a slightly wobbly outline because fabric shifts. That is normal.

Now add the details that make the shape usable as a real pattern.

Add seam allowance if your tracing follows the seam line. A common sewing allowance is 3/8 inch or 1/2 inch, but use what makes sense for how you sew. For knit T-shirts, many people prefer a smaller seam allowance 3/8 inch because it is easier to handle on a serger or stretch stitch.

Add hem allowance at the bottom edge and sleeve hem. If the original shirt has a 1-inch hem, you can copy that. If you want more room to adjust later, add extra length and trim after fitting.

Mark the grainline. On a shirt, the grainline usually runs parallel to the center front or center back. For the sleeve, align it with the center of the sleeve from cap to hem.

Add notches at key matching points:

• Shoulder point

• Front armhole

• Back armhole

• Sleeve cap center

• Side seam hem

  
  

These marks help when sewing the test version.

The pin marks turns the copied shape into a draft pattern.

Check the pattern before you cut fabric

A 30-minute block is fast, but it still needs a quick check. Before cutting into good fabric, Walk your pattern pieces.

Start with the shoulder seams. The front and back shoulder should be similar in length unless the original garment has a design reason for a difference.

Check the side seams. The front and back side seams should match from underarm to hem. If one is slightly longer because the shirt shifted, true the lines so they sew together cleanly.

Then check the armhole and sleeve. Walk the sleeve cap around the armhole with a measuring tape. The seam lines should be close enough to sew smoothly, especially for a knit T-shirt.

Make a quick test garment from fabric with similar stretch and weight. This matters. A block copied from a soft jersey T-shirt will not behave the same way in a stiff woven cotton. Fabric changes fit. I would suggest adjusting the pattern if you plan to use the same block for woven fabric that do not stretch.

Try on the test garment and look for simple clues:

• Shoulder seam sits where you like it

• Neckline lies flat

• Sleeve moves comfortably

• Side seams hang straight

• Hem length feels right

  
  

Make notes directly on the test garment or pattern. A block improves each time you use it.

Use the block to design new garments

Once the pattern fits, you have a personal base to work from. This is where the method becomes powerful.

You can change one feature at a time. Raise or lower the neckline. Widen the body. Add length. Shorten the sleeve. Shape the waist. Split the front to create a button placket. Each change starts from a block you already understand.

Keep the original copy intact. Trace off new versions instead of cutting into your master block. Label each variation with the date, fabric type, and adjustment. That habit saves confusion later.

Copying a garment is one of the quickest ways to understand pattern shapes. A loved T-shirt or dress shirt gives you fit information that measurements alone cannot capture. With a corkboard, paper, pins, and about half an hour, you can create a useful block pattern and start building new garments from a shape you already trust.

The Reyburn School of Apparel Patternmaking