Fishing Reel Backing Calculator and Line Capacity Tool

Calculate how much backing and main line fits on your fishing reel, or use Capacity Mode to estimate how much of one line your spool will hold.

• Calculate mono backing for braid, fluorocarbon, or other main line

• Estimate total reel capacity when you do not want to use backing

• Use actual line diameter for more accurate spool-fill results

• Save money by using only the amount of premium line you need

ReelCalc helps anglers build better fishing line setups by combining reel capacity, line diameter, backing, and working line length. The calculator is prefilled with an example setup so you can see how the results work, then you can replace the numbers with your own reel capacity and line choices.

Not sure what your fishing line diameter is? Search the ReelCalc Line Database to find your exact line size.

Don’t have your reel nearby? Check out the example values in the calculator above

Using Japanese PE line ratings? Try the PE Line Capacity Calculator to estimate PE braid capacity, backing, and total reel fill using PE sizes, meters, yards, and backing diameter.

Enter reel specs

Capacity & LB test of line

Enter line diameters

Good line and backing diameter

Save money

No guesswork