Fly tying calculator: materials per pattern and hook size
Choose a pattern, a hook size and how many flies you want to tie. See thread, wire, dubbing and feathers per fly and for the batch, and how many flies each packet covers.
Your materials (estimate)
Gold-Ribbed Hare's Ear recipe
- Hook
- #14 standard-length hook (nymph hook), shank about 8.6 mm
- Thread
- 8/0, olive or brown
- Size scale (k)
- 1 compared with a #14 standard hook
- Recipe from
- Orvis: Gold-Ribbed Hare's Ear
Materials per fly and for 12 flies (estimate)
| Material | Per fly | For 12 |
|---|---|---|
| 8/0 thread, olive or brownTying thread (including waste) | 100 cm | 12 m |
| Hare guard hair or pheasant tail fibresTail | 11 fibres | 132 fibres |
| Hare's mask dubbingBody and thorax | 0.033 g | 0.39 g |
| Oval gold tinsel or fine gold wireRib | 7.7 cm | 92 cm |
Flies per packet (estimate)
| Pack | Use per fly | Flies per pack | Packs for 12 |
|---|---|---|---|
| Semperfli 8/0 thread, 110 m spool | 100 cm | 110 | 1 |
| Semperfli 8/0 thread, 220 m spool | 100 cm | 220 | 1 |
| Semperfli wire or tinsel, 30 m | 7.7 cm | 391 | 1 |
| Dubbing pack, 1 gLimiting material | 0.033 g | 30 | 1 |
With these pack sizes, Dubbing pack, 1 g runs out first: about 30 flies per pack.
Dubbing grams and thread length per fly are estimates: no authoritative source publishes them. Quantities scale with hook size, so check your own tying before you buy.
How this calculator works
We work out the shank length from the Mustad R30AP size chart, which gives an overall length of 8.3 mm at size 18 up to 18.5 mm at size 8. The shank is 75% of that, lengthened by 1.3 for 2XL or 1.6 for 3XL hooks. Dividing by the shank of a size 14 standard hook gives a scale factor, k.
Lengths such as floss, chenille and foam scale with k. Dubbing scales with k squared, because the body gets fatter as well as longer. Counts such as hackle feathers, herl strands and marabou stay fixed. Thread starts at 80 cm for a size 14 fly, rises by half for lures, and has 20 cm of waste added. Rib wire is 9 cm at size 12 with a 4 cm minimum. Dubbing is 0.02 g for a size 14 dry fly, 0.045 g for a size 12 nymph and 0.1 g for a size 8 lure.
The thread and dubbing figures are estimates. We found no authoritative source for how much a fly uses, so treat them as a planning guide: your tension and style will change them.
Flies per packet divides a typical pack by the use per fly: Semperfli 8/0 thread in 110 m or 220 m spools, 30 m of Semperfli wire, a 1 g dubbing pack and a Whiting 100 pack of hackles. The material that runs out first limits your batch. Recipes come from pages such as Orvis on the Adams, Wikipedia on the Elk Hair Caddis and Fish4Flies on the Black Pennell, and every tyer varies them.
Fond of another craft? Our yarn tree calculator works out how much yarn a Christmas yarn tree needs.
Frequently asked questions
How much thread does one fly use?
We estimate 80 cm of 8/0 thread for a size 14 fly, scaled by hook size, plus 20 cm for waste and whip finishing. That is 100 cm at size 14, so a 110 m spool ties about 110 flies. Lures and boobies use about half as much again. No authoritative source publishes this figure, so it is an estimate.
What is the limiting material?
It is the material in your recipe whose pack covers the fewest flies. For a size 14 Elk Hair Caddis it is dubbing: a 1 g pack at 0.02 g a fly gives 50 flies, while a 110 m thread spool gives 110. Buy extra of the limiting material first.
Why does hook size change the quantities?
A bigger hook has a longer shank, so thread, wire, floss and chenille run longer, and dubbing grows faster because the body is fatter as well as longer. We calculate shank length from the Mustad R30AP size chart. Source: Mustad R30AP.
Are the recipes the only way to tie these flies?
No. Every tyer varies materials, sizes and colours. For example, Orvis ties the Adams with grey dubbing and grizzly hackle tips, while older recipes use muskrat fur. Use the recipe as a starting point and edit it to suit your box. Source: Orvis: Adams dry fly.
What do 2XL and 3XL hooks mean?
They are hooks with a shank two or three sizes longer than normal. We multiply the shank by 1.3 for 2XL and 1.6 for 3XL, so a long-shank lure hook uses noticeably more thread and wire than a standard hook of the same size.
Why are some patterns missing?
We only list patterns where we could read a recipe on a reputable page. Kate McLaren and Cruncher are not yet included, and the list is capped at ten patterns. Wikipedia describes the Elk Hair Caddis, and Fish4Flies lists the Black Pennell, among others. Source: Wikipedia: Elk hair caddis.