How To Draft A Pattern

Pattern Drafting Basics

You don't need special software to draft a pattern. Most people I train start with graph paper, a meter stick, and a curve ruler. The whole process takes about three hours for a basic bodice block if you know what you're doing. Two hours if you've done it before. Four hours if you're measuring your own body for the first time and second-guessing every number. Start with your measurements. Bust, waist, hip, shoulder width, back length. Write them down. Double-check them. I once drafted a full garment using a measurement set where someone had recorded circumference instead of individual panel widths, and the front and back pieces didn't match by nearly three inches at the side seam. You learn to verify everything twice. Lay out your paper. Draw a center front line and a center back line as your anchors. These are vertical reference lines that everything else builds from. Your first horizontal line should be the bust level — measured straight across from the side seam. From there, you work down to the waist and hip using your own measurements divided by four for each quarter-panel section.

The shoulder slope is where beginners go wrong. Most people draw it flat or guess at the angle. It's not flat. A standard adult shoulder slopes about one inch from the neckline down to the armhole over the span of the shoulder width. If you're drafting for someone with a broader or narrower frame, adjust proportionally. I use a small set square to lock in that angle rather than trying to eyeball it freehand. Armhole depth is measured from the shoulder point straight down. For a basic block, that's approximately one quarter of the bust measurement plus two inches. That extra two inches accounts for ease and mobility. Without it, the armhole sits too high and the garment restricts movement. I've seen this repeatedly in sample rooms where a pattern was drafted from finished garment measurements instead of body measurements, and the resulting armholes were functional but barely passable for anything beyond a tight fashion piece. Now draw the curve. This is where a French curve or flexible curve ruler earns its keep. The armhole curve connects the shoulder point to the side seam. It needs to be smooth, continuous, and slightly deeper in the front than the back. The back armhole sits higher because the shoulder blade creates more curvature in the upper back. Start from the shoulder point, sweep through a gentle arc, and meet the side seam line at the marked depth. Check the curve against the back piece to make sure they mirror each other properly when the pattern is folded.

Dart placement is the next decision point. A standard bodice block uses a bust dart and a waist dart. The bust dart points toward the apex — the fullest part of the bust — and typically angles downward at about fifteen degrees from horizontal. The waist dart is centered on the natural waistline and tapers to nothing at both ends. Dart width depends on how much shaping you need. A standard dart might take up one and a half to two inches of fabric. More curvature in the torso means a wider dart or additional darts like a side seam dart or a second waist dart. I had a client once who had a very pronounced sway back, and a standard single-dart pattern gapped at the upper back no matter what we tried. We ended up adding a complementary curved dart to the back piece and adjusting the shoulder slope by an additional quarter inch. The gap closed completely after that. Standard blocks don't account for every body variation, so be ready to adapt. Once all the lines and darts are drawn, cut them out. Use a sharp pair of fabric shears or an X-Acto knife on a cutting mat. The edges need to be clean. Jagged cuts throw off your seam allowances when you transfer to fabric. After cutting, trace each piece onto a new sheet of paper or cardstock for durability. Label every piece — front, back, left, right, grainline arrow, cut two. Grainline goes parallel to the fold or selvage of the fabric. Getting this wrong means the garment will twist on the body after wear and washing.

Test the pattern with muslin or calico before cutting into your final fabric. Pin the seams together and try it on. Check for pulling, gaping, excess fabric, and proper drape. Adjust as needed. The test garment doesn't have to look pretty. It has to tell you whether the draft works. The whole process from first measurement to test garment usually takes a day for a beginner. An experienced drafter can do it in a few hours. The shortcut most people miss is building a reliable personal measurement system. Once you have a consistent method for recording and translating body measurements into pattern dimensions, drafting becomes faster and more accurate every time. That's the part that doesn't show up in tutorials — the repetition and refinement that happens outside the actual drafting steps.