## Bakers Percentage for Starter

I've been trying to get better at converting my recipes to baker's percentages. I am struggling with how to determine the calculation for how much starter to use to end up with the correct amount of levain for the final dough.

In my recent recipe I took my standard starter and used 3.7 ounces for the seed and added 3 oz. Durum, 2 oz. white rye, 4 oz. bread flour, and 2 oz. Spelt flour. I added 7 oz. water. The overall hydration of the starter is now 64%.

I ended up using 15.5 oz. of levain from the above starter in the final dough. By calculating the following method I determined that this contains 6.01 oz. water, and 9.49% flour.

IW (ingredient weight, water) = IP (Ingredient %) x (TW (total weight) / TP (Total %)

64% x (15.5 /164) = 6 oz.

I then subtracted this from 15.5 to get the flour weight of 9.49 oz.

My question is how do you determine how much seed starter to use to create the 15.5 oz. of levain?

I made almost double the amount I needed since I didn't bother to figure this out originally, but since I would like to give people who want to try my recipe the option of just making enough levain I need to figure this out.

Any help would be appreciated.

Thanks

Ian