THE NUMBERS, EXPLAINED
How to use this calculator.
Matches stated yarn length and rounds purchases to complete skeins. Equal length does not guarantee matching gauge, fibre behaviour or finished fabric.
Start with your inputs
Enter original yarn length (m), original yarn weight (g), original total weight (g), replacement skein length (m), replacement skein weight (g). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Original yarn length (m) | 200 |
| Original yarn weight (g) | 100 |
| Original total weight (g) | 400 |
| Replacement skein length (m) | 150 |
| Replacement skein weight (g) | 50 |
A worked example
With the example inputs above, required yarn (m) is 800. Change the inputs to explore your own scenario.
Putting the example numbers into the formula
Required yarn (m)
(200) × (400) ÷ (100) = 800
| Result | Example answer |
|---|---|
| Required yarn (m) | 800 |
| Replacement skeins | 6 |
| Purchased weight (g) | 300 |
How this is calculated
Required yarn (m)
a × c ÷ b
Replacement skeins
roundUp(a × c ÷ b ÷ d)
Purchased weight (g)
roundUp(a × c ÷ b ÷ d) × e
Symbols and units
- a
- Original yarn length (m)
- b
- Original yarn weight (g)
- c
- Original total weight (g)
- d
- Replacement skein length (m)
- e
- Replacement skein weight (g)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Calculation steps and notation
roundUp(x) rounds up to the next whole number. Values within two floating-point rounding units of an integer are treated as that integer.
Assumptions and limits
Matches stated yarn length and rounds purchases to complete skeins. Equal length does not guarantee matching gauge, fibre behaviour or finished fabric.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Required yarn (m); Replacement skeins; Purchased weight (g). The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Matches stated yarn length and rounds purchases to complete skeins. Equal length does not guarantee matching gauge, fibre behaviour or finished fabric.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax: algebra and proportional reasoning ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
Read the quality report →