Fishing reel line capacity calculator
Estimate how much line your spool holds when you change line diameter, using the capacity printed on the spool.
Enter your values, then calculate.
Method and limitations
New length = stated length × (stated diameter ÷ new diameter)². Convert yards to metres by multiplying by 0.9144, or metres to yards by dividing by 0.9144. Both diameters must be in millimetres. The result is rounded to the nearest metre and yard.
Sources
No external reference is documented for this calculation; its method and limitations are described above.