12 WPI — approximate Bulky category is the example result. Read it using the units and relationship stated below.
Yarn Weight uses wraps per inch.
Turning measured dimensions into a material plan
For yarn weight, the relationship is Map wraps per inch to the displayed approximate weight band. Wrap tension and yarn construction affect this screening estimate; use the supplier label for the final category. The amount depends on the supplied wraps per inch, rather than a live market price or a value imported from another record. Material quantities begin with the actual surface, volume or part dimensions. A footprint and a sloped surface are different measurements. Pack sizes, offcuts and layout can increase the order above the geometric requirement.
What the model includes
Map wraps per inch to the displayed approximate weight band. Wrap tension and yarn construction affect this screening estimate; use the supplier label for the final category. Check the dimension convention and include openings only where the model has a corresponding input. A percentage allowance is a planning adjustment, not a layout simulation. Retain the source drawing or measurement sheet next to the result. Confirm the supplier unit before ordering. Area, volume, board feet and mass cannot be substituted without the thickness or density relationship. Structural suitability and fixing details are outside a quantity estimate.
Example with the supplied inputs
Wraps per inch: 12. Result: 12 WPI — approximate Bulky category. The values are illustrative.
Compare one changed input
Wraps per inch changes from 12 to 13.2. The result becomes 13.2 WPI — approximate Worsted / Aran range category. All other inputs remain fixed.
Calculation rule
Map wraps per inch to the displayed approximate weight band. Wrap tension and yarn construction affect this screening estimate; use the supplier label for the final category.
Inputs and output
| Input | Example value | Entry convention |
|---|---|---|
| Wraps per inch | 12 | Use the source quantity represented by wraps per inch. Keep the counted population fixed and avoid mixing a unit value with a period total. |
Output: 12 WPI — approximate Bulky category is the example result. Read it using the units and relationship stated below. Use the formula to distinguish a cash amount, count, percentage or ratio.
How to use the page
Collect the inputs
Gather Wraps per inch. Use one period and the units shown in the form.
Run the calculation
Enter the values and select the action. The calculation rule above explains how the inputs produce the result.
Compare a scenario
Change Wraps per inch on its own, keeping the other inputs fixed. Read both results before changing another assumption.
Worked example
With the example inputs listed above, the result is 12 WPI — approximate Bulky category.
Change Wraps per inch from 12 to 13.2 while keeping every other value fixed. The result becomes 13.2 WPI — approximate Worsted / Aran range category. This comparison isolates that input; it does not forecast how other variables will respond.
Check the stated formula, units and limits before using the result in a decision.
Keep the displayed formula, input units and model scope with the result. Corrections or questions can be sent through the request section on this page.
Content updated: October 11, 2026