Constructing Graded Spec Sheets
Constructing Graded Specification Sheets
A graded spec sheet is a numeric chart, not a sketch-only doc. Minimum viable structure:
Style #: ______ Style Name: ______ Date: ______ Base Size: M
Front/Back sketch with lettered/numbered callout points (A, B, C...)
| POM Code | Measurement Point | Tolerance | XS | S | M(base) | L | XL |
|----------|--------------------------|-----------|------|------|---------|------|------|
| A | Chest (1" below armhole) | ±0.25" | 18 | 19 | 20 | 21.5 | 23 |
| B | Waist | ±0.25" | 16 | 17 | 18 | 19.5 | 21 |
| C | Hip | ±0.25" | 19 | 20 | 21 | 22.5 | 24 |
| D | Sleeve Length | ±0.125" | 23.5 | 24 | 24.5 | 25 | 25.5 |
| ... | ... | ... | ... | ... | ... | ... | ... |
Construction notes: [seam types, stitching details]
Revision log: [date, change, reason]
Every row = one POM. Every column = one size. Base size populated first, other sizes derived via the grade rule for that POM.
Progress:
- Step 1: Confirm base size and full size range with target market data
- Step 2: Gather/finalize garment sketch with front + back views
- Step 3: List every POM (point of measure) needed for pattern-making
- Step 4: Populate base size measurements (from fit sample or reference garment)
- Step 5: Establish grade rule (increment) per POM, per size break
- Step 6: Calculate graded measurements for all sizes up and down from base
- Step 7: Add tolerances per measurement point
- Step 8: Add construction guidelines and stitching/seam details
- Step 9: Add notes/comments field for edge cases
- Step 10: Review against fabric properties; adjust ease as needed
- Step 11: Send to manufacturer for pattern/sample; log any revisions
Step 1 — Base size first: Always grade outward from the middle size (e.g., M in XS–XL). Never grade sequentially from XS upward — errors compound.
Step 5 — Grade rules: A grade rule is the fixed increment added/subtracted per size break for each POM (e.g., chest +1" per size, sleeve length +0.5" per size). Grade rules can differ above and below the base size, and often differ between adult vs. plus/extended sizing — verify company grading standards or industry standard grade rules (e.g., ASTM) before assuming linear scaling.
Step 6 — Calculation pattern:
Size measurement = Base measurement + (grade rule × number of size breaks from base)
Example: Base M chest = 20". Grade rule = +1"/size. S = 20 - 1 = 19". XS = 20 - 2 = 18". L = 20 + 1 = 21". XL = 20 + 2 = 22". (Grade rules can be non-uniform — e.g., torso length may grade at half the rate of chest.)
Step 7 — Tolerances: Tighter tolerance for structured/fitted points (necklines, cuffs: ±0.125"), looser for flowy/relaxed points (hem sweep, body length: ±0.5"). Never leave tolerance blank — it's the manufacturer's acceptable pass/fail range.
Example 1: Input: T-shirt, base size M, chest = 20", grade rule +1"/size, range XS-XL, standard tolerance ±0.25" Output:
| POM | Chest | XS | S | M | L | XL |
|---|---|---|---|---|---|---|
| A | Chest (±0.25") | 18 | 19 | 20 | 21 | 22 |
Example 2: Input: Fitted dress, base size 8, waist = 28", grade rule +1" for sizes 8-14, then +1.25" for sizes 16-20 (extended grade), tolerance ±0.125" at waist Output:
| Size | 4 | 6 | 8 (base) | 10 | 12 | 14 | 16 | 18 | 20 |
|---|---|---|---|---|---|---|---|---|---|
| Waist | 26 | 27 | 28 | 29 | 30 | 31 | 32.25 | 33.5 | 34.75 |
| Note: flag the grade rule shift in the notes field so manufacturer doesn't apply single flat rate. |
- Grade from base size outward, never end-to-end sequentially.
- Use consistent measurement points (POM codes) across all tech pack pages (spec sheet, POM sheet) so manufacturers cross-reference without confusion.
- Reference an actual fit sample or well-fitting existing garment for base measurements — don't estimate from a size chart.
- Adjust grade rules for fabric behavior: wovens/structured fabrics typically need full grade increments; stretch knits may need reduced increments since fabric absorbs some size difference.
- Keep a visible revision log on the sheet itself (date, POM changed, old value, new value, reason) — critical for repeat production runs.
- Round graded values to the fraction system your factory uses (1/8", 1/4", or mm) — mixed units cause manufacturing errors.
- Confusing this with a consumer size chart — spec sheets are for manufacturers/pattern-makers, with construction-specific measurement points (e.g., "1" below armhole"), not generic body measurements.
- Applying one flat grade rule across the entire size range when extended/plus sizes often require larger increments.
- Omitting tolerances — without them, manufacturers have no defined acceptable variance and QC becomes arbitrary.
- Forgetting to update the graded spec sheet after fit sample revisions, causing future production runs to use outdated numbers.
- Grading only the sketch's obvious dimensions while missing secondary POMs (e.g., pocket placement, collar height) that also need to scale with size.