Advanced fishing reel line capacity estimator

This calculator allows you to work out how much line you will get on a reel if you are using sections of line of two different thicknesses.

For calculations with only one thickness of line use our standard Fishing reel line capacity estimator.

You need the reel capacity from the manufacturer’s literature, you then enter the length and diameter of the first section of line you wish to use. You then enter the diameter of the second line you wish to use. The calculator will give an estimate of how much line of that second thickness you will get on the reel.

Example 1, the published capacity of your reel is 300m of 0.60 mm line. You want to use 150m of 0.76 mm monofilament as your main line and want to know how much backing you will get on if you use 0.31 mm braid. Enter the figures into the estimator, you will see the result, 222m of backing with a total line length of 372m.

Example 2, the manufacturer states your reel holds 200m of 0.38mm line. You want to use a 150m top shot of 0.23mm braid. How much 0.35mm monofilament backing will you need to put on the reel first? Enter the figures into the estimator, you will see the result, 171m of backing with a total line length of 321m.

Below are the line diameters for Berkley Big Game, a good quality mono-filament line on widespread sale in Thai fishing tackle shops. Berkley Big Game is quite a thick (large diameter) line for it’s breaking strain, most lines of similar breaking strain are thinner.

Berkley Big Game line diameter
lb in mm
8 0.011 0.27
10 0.012 0.30
12 0.014 0.35
15 0.015 0.38
20 0.018 0.45
25 0.019 0.48
30 0.022 0.55
40 0.024 0.60
50 0.028 0.71
60 0.030 0.76
80 0.035 0.88
100 0.039 0.99
130 0.044 1.11

The capacity estimator below works in yards and inches.

Please note the calculated line capacity is approximate, line stretch, how tight the line is wound on the spool and other factors will affect line capacity.