How to draft a bodice block from your measurements
Updated · Fernhart Labs
Short answer
A close-fitting bodice block is drafted on a frame half your bust measurement plus 5 cm wide (10 cm of ease around the body) and as long as your back waist length. You mark the armhole line at your armhole depth below the nape, draw the back and front necklines and shoulders, set the bust point 2.5 cm below the armhole line, add a shoulder bust dart and waist darts, then true the darts and check that every pair of seams is the same length.
You need eight measurements (bust, waist, neck, shoulder length, back width, chest width, back waist length and armhole depth), plus the high bust and bust span if you want the dart sized to you.
The measurements to take
Measure over the underwear you will wear with the garment, with a tape held snug but not tight. Tie a string around your natural waist first: several measurements start from it.
| Measurement | How to take it |
|---|---|
| Bust | Around the fullest part of the bust, tape level across the back. Wear the bra you will wear the garment with. |
| High bust | Around the chest under the arms and above the bust, tape level. Used to size the bust dart. |
| Waist | Around the natural waist: the narrowest part, where you bend sideways. Tie a string there; it marks the waist for the length measurements. |
| Neck | Around the base of the neck, over the bump at the back of the neck and just above the collarbones. |
| Shoulder length | From the side of the neck (where a necklace sits) to the shoulder bone at the tip of the shoulder. |
| Back width | Across the back, from armpit crease to armpit crease, about 10–12 cm (4–5 in) below the neck bone. Arms relaxed. |
| Chest width | Across the front, from armpit crease to armpit crease, halfway between the neck and the bust. |
| Back waist length | Down the centre back, from the neck bone to the waist string. |
| Armhole depth | Optional. From the neck bone straight down to the level of the armpits (a ruler held under the arm marks it). |
| Bust point span | Optional. Straight across from one bust point to the other. |
Armhole depth, high bust and bust span are optional: if you leave them out, they can be estimated from the others, but measured values fit better.
How much ease to add
A block is not your body: it needs room to breathe and move. The close-fitting block below adds 10 cm (about 4 in) at the bust, the ease built into a frame of half bust + 5 cm. Looser blocks, for jackets or relaxed tops, add more. Ease at the waist is smaller and comes from how much the waist darts take in.
Draft the block, step by step
These are the main construction lines of the close-fitting block in the style of Winifred Aldrich's Metric Pattern Cutting for Women's Wear. Draft half the body (centre back to centre front) on pattern paper, in centimetres.
- Draw the frame. Draw a rectangle half your bust + 5 cm wide. Mark the nape at the top left corner (centre back) and square down. The back neck point sits 1.5 cm above the nape.
- Mark the armhole and waist lines. Square across at your armhole depth + 0.5 cm below the nape for the armhole line, and at your back waist length below the nape for the waist line.
- Back neck and shoulder. Make the back neck width your neck measurement ÷ 5 − 0.2 cm and curve the back neckline from it to the nape. Draw the shoulder line at a slope (18° below horizontal is a common starting point) at your shoulder length plus 1 cm for a small back shoulder dart.
- Back width. From centre back, mark half your back width + 0.5 cm across the back, to guide the back armhole curve.
- Front chest and bust point. From centre front, mark half your chest width plus half the bust dart's width across the chest. Place the bust point 2.5 cm below the armhole line, at half your bust span from centre front.
- Front neck, shoulder and bust dart. Draw the front neckline and the front shoulder (a 22° slope is a common starting point), with a shoulder bust dart pointing to the bust point. Its width comes from the size chart or the difference between your bust and high bust.
- Armholes, side seam and waist darts. Curve the back and front armholes through the back and chest width marks to the armhole line, draw the side seam, and divide the difference between the block's waist and your waist + ease into waist darts at the back and front.
- True the darts and check the seams. Fold each dart closed in the direction it will be pressed, redraw the seam line straight across it, and open it out again. Then check that the back and front shoulders are the same length (with the back dart closed) and that the side seams match.
Questions
What is a bodice block or sloper?
A basic close-fitting pattern of the upper body, without style details, seam allowances or design ease. You trace it and change it to make the patterns for actual garments. "Block" is the usual British term, "sloper" the American one.
How much ease should a bodice block have?
A close-fitting block adds about 10 cm (4 in) around the bust: the frame is half the bust plus 5 cm. Looser blocks add more.
What measurements do I need for a bodice block?
Bust, waist, neck, shoulder length, back width, chest width and back waist length, plus armhole depth. The high bust and bust span let the bust dart be sized to you.
Do I need a high bust measurement?
It is optional. It measures the chest above the bust, and the difference between it and the full bust is a good guide to how big the bust dart should be.
Should I add seam allowance to a block?
No. A block is drafted without seam allowances, which makes it easier to alter. Add them when you trace off a garment pattern.
How do I check that my block fits?
Sew a test bodice (a toile or muslin) in plain fabric and try it on before you use the block for real garments: pull lines and gaps show where it needs adjusting.
Sloper Studio: Sewing Patterns
Made-to-measure sewing patterns drafted from your measurements.
Sloper Studio drafts this block (after Winifred Aldrich's close-fitting block) with a set-in sleeve, plus skirts, trousers and a knit T-shirt, from your measurements. It tells you which measurement looks wrong and why, then checks every draft before you print: seams that sew together are the same length, darts are true and the pieces go around the body plus the ease. It prints a tiled PDF for Letter or A4, an A0 PDF for a copy shop or a projector view, and works offline in English, Spanish, French, Italian and German.
Sources
- W. Aldrich, Metric Pattern Cutting for Women's Wear, 5th ed., Wiley-Blackwell (2008): the close-fitting bodice block, as summarised in secondary sources
- Sloper Studio's drafting engine: the construction lines and conventions above, with shoulder slopes and dart placement marked as adjustable conventions Sloper Studio