Lets take the mystery out of leaders.

First principal, the leader butt, the section that attaches to the fly line must be close to the size, diameter of the fly line, this is to aid the transfer of energy down through the fly line to the fly via the leader.

If we used the example of a water pipe and suddenly reduced the joining pipe we would had added pressure, not a smooth flow. Our fly line to leader is the same.

Normally the larger the fly the smaller/shorter the leader. Try using a 15 foot leader on a 2/0 fly and then a 6 foot leader and the result will be very noticeable. However a size # 20 fly on a 15 foot leader, its beautiful to cast with great presentation onto the water, it rolls over well in the sky, all you could ask for. Here we are describing a leader used with a 10 foot or less single handed rod.

Double Handed rods can use a far longer leader system on all sizes of flies.
Or you can simply buy your Tapered leaders like I do.

This is a general rule however there are a number of sizes of lines and hooks that break the rules, so please only use this table as a guide only.

Now lets suggest a few common leaders for different applications. The most common knot to join different sections of your leader material is the blood knot, the loop to join your leader to the fly line, a double surgeon's knot. This will allow the leader to hang squarer of the leader.

I do not believe in nail knots for joining the leader to the fly line for a number of reasons. And we will not go into which is the best knot or why because this could produce a book on the subject which maybe endless. The images below are not to scale.

All Round Saltwater Leader 8 foot 6 inch
Butt end 36"x30lb........... .....30"x20lb.......... 12"x15lb...........24"x12lb ........ . 24"x10lb

Heavy Saltwater 6 foot
Butt end ........6feetx40lb....................... ......2feetx15lb................tippet 1 footx 20 to 80lb

Tapered Nymph 9 foot
Butt end 28"x.019 .....14"x.017 ....12"x.015....10"x.013...6"x.011..6"x.009..6"x.007..20"x.005

Tapered Nymph 14 foot this leader can be extended out to 16feet with a 6lb tippet.
Butt end 24"x.021............48"x.015..................36"x.013...........24"x.011......36"x.009 - 9.5lb

General Purpose 8 foot 6 inch
Butt end 12"x.017.14"x.015....14"x.013....12"x.011....10"x.009...10"x.008..12"x.007...18"x.005

Flats Type 15 foot for windy conditions and spooky fish, a stiff butt section material is required Butt end ....5feetx30lb............3feetx25lb..........2feetx20lb......2feetx12lb.... 3feet of tippet size

Large Salmon/Steelhead 9 foot this leader can be extended out another 8inchs with a longer tippet also
Butt end 30"x.023........20"x.021.........12"x.019.....8"x.017....6"x.015..6"x.012......18"x.01

Distance 11 feet for Dry fly use
Butt end 10"x.017..20"x.015...20".013.......20"x.011.....12"x.009.....18"x.007........30x.006

Dry Fly 10 foot 6 inch
Butt end 10"x.017..20"x.015.....20"x.013......20"x.011......14"x.009....18"x.008......24"x.007

Dry Fly 7 foot 6 inch
Butt end 10"x.017..14"x.015..14"x.013.....10"x.011....10"x.009.....12"x.008.........20"x.007

25 - 50 - 25 this is made up of 25% Butt section, 50% mid section and 25% tippet section with the butt being stiff and the mid and tippet sections soft and using approx 35% step down in diameter.
Butt end 30"................................18"..............12"............. 6"........6".....6"........18"

60 - 20 - 20 This is made up of 60% butt, 20 mid and 20% tippet section. again with a stiff butt section and softer mid and tippet sections.Again use a 35%step down or .002, this later step down is a produces a better roll over.
Butt end 48"....12"..........12".........8".........8"..........8".......12......12.........tippet size

 

Too hard to build/make your own tapered leaders, do what I do, buy the best tapered leaders on the market, Talon Tapered Leaders