AFFTA Official Fly Line Specifications & Weights

The American Fly Fishing Trade Association (AFFTA) provides standardized weights for fly lines, which you can find below. While most anglers simply use the general line weight measure when matching a line to a rod, occasionally more detailed information is useful. The table below provides the official measurements in both grains and grams. This may also be useful when trying to determine what line weight an unmarked line is, as you can simply place it on a precision scale.

Standard Single-Handed Fly Lines

(Weight is for the first 30' of line minus level tip)

 Line Weight

Weight in Grains

Low

Weight in Grains

Target

Weight in Grains

High

Line Weight

Weight in Grams

Low

Weight in Grams

Target

Weight in Grams

High

1 54 60 66 1 3.5 3.9

4.3

2 74 80 86 2 4.8 5.2 5.6
3 94 100 106 3 6.1 6.5 6.9
4 114 120 126 4 7.4
7.8
8.2
5 134
140
146
5 8.7
9.1
9.5
6 152
160
168
6 9.9
10.4
10.9
7 177
185
193
7 11.5
12
12.5
8 202
210
218
8 13.1
13.6
14.1
9 230
240
250
9 14.9
15.55
16.2
10 270
280
290
10 17.5
18.15
18.8
11 318
330
342
11 20.6
21.4
22.2
12 368
380
392
12 23.8
24.6
25.4
13 435
450
465
13 28.2
29.2
30.2
14 485
500
515
14 31.1
32.4
33.7
15 535
550
565
15 34.3
35.6
36.9

Standard Spey Fly Lines

  Shooting Heads Short Belly Medium Belly Long Belly
Line Style H S M L
Head Length 30'-50' 50'-60' 60'-70' 70' plus
Weight Point 40'
55'
65' 80'
Line Weight Increment grains / grams
grains / grams
grains / grams
grains / grams
6 250 / 16.2 420 / 27.3 460 / 29.9 600 / 39
50
7 300 / 19.5 470 / 30.5 510 / 33.1 650 / 42.2
60
8 360 / 23.4 530 / 34.4 570 / 37 710 / 46.1
70
9 430 / 27.9 600 / 39 640 / 41.6 780 / 50.6
80
10 510 / 33.1 680 / 44.2 720 / 46.8  860 / 55.8
90
11 600 / 39 770 / 50 810 / 52.6 950 / 61.7
100
12 700 / 45.5 870 / 56.5 910 / 59.1 1050 / 68.2

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