The Fresh Loaf

News & Information for Amateur Bakers and Artisan Bread Enthusiasts

Calculating Final Dough Hydration from Baker's Percentages

mlucas's picture

Calculating Final Dough Hydration from Baker's Percentages

When baking with any type of starter/levain/biga, it seems pretty important to know the final dough hydration of a recipe, as that is a much better way to gauge the feel of the dough than just the base hydration. (especially when a large amount of starter is used)

Of course, if the hydration of the starter matches the hydration of the dough recipe, there's no need to calculate. But usually this is not the case...

I did some math and came up with the following formula that you can use to caluculate the final dough hydration, just based on the Baker's Percentage numbers (i.e. without taking any weights into account).

fdh = final dough hydration
h = hydration (the ratio of water to total flour in the recipe)
sh = starter hydration (the ratio of water to flour in the starter)
sp = starter percentage (the ratio of starter to flour in the recipe)

If you know the amount of starter you want to use, its hydration, and the final dough hydration you want, you can solve for the hydration (ratio of water to flour) you need in the recipe:


I'm surprised that the formulae are so complicated, but I guess that's math for you. I really wish all recipes would list the final dough hydration along with the other numbers, as it's annoying to have to calculate it yourself!

I'd appreciate any comments as to whether this is useful or not, and checking of my math. Thanks!


cgmeyer2's picture

reminds me of calculus classes.

thank you this  helps a lot


DocKinsey's picture

Your work providing these formulae is very useful.  I am forever experimenting with hydration looking for a combination that will allow me to handle the dough and provide the crumb I want.  I'm going to put your formulae in an Excel spreadsheet with my Baker's Percentage calculator so I can better keep up with my trials.


ehanner's picture

Forgive my penmanship. This is a work sheet I used today to put together a bread for tomorrow. The note starts off with my not shown mental calculation that I need about 200 grams of starter for my 800g of flour for it to be 25% prefermented dough. I keep that starter at 100% so it's half water, half flour. Then I add the amount of flour to arrive at 800g and multiply by the hydration percent I want to arrive at for the final dough. In this case 70% or .70 X 800 = 560g of total water less the 100g from the starter. So I need 460g additional water. This is easy and doesn't require any algebra on my part.

2% salt =16g


wally's picture

You can make this rocket science, but as you've captured in a picture, Eric, it doesn't need to be!


subfuscpersona's picture

I saved it to my computer for future reference. I appreciate that you took the time to work it out and share with the rest of us on TFL.


mlucas's picture

@DocKinsey & subfuscpersona
Thanks for the comments -- it was mostly a thought experiment for me so I'm glad to see it might be useful. I was hoping that when I solved for final hydration, it would be an easy enough formula to just do in your head upon looking at a recipe, but obviously it's not! Which is a good reason for recipes to include it as a quick reference thing, to help you understand the character of the bread at first glance.

I agree, once you get down to actually baking and using real weights, it's probably easier to skip the complicated formula. I just felt that there should be a way to calculate final hydration based on Baker Percentages only, without resorting to using any measurements.


davidg618's picture

(I didn't check your math:-)

I whole heartedly agree with you. Given the final dough's hydration, the percentage contribution of each flour and ingredient, and either the percentage of starter/poolish/biga/sponge, and it's hydration, or its flour's percentage contribution to the final dough, and its hydration. we can reproduce the formula for any amount of dough we want.

My pet peeve is bread formula's (many of our favorite books contain them) that leave out one or more of the necessary percentages, causing us to have to calculate them from the ingredient weights. Furthermore, I like formula that list the percentage of pre-fermented flour over formula that list the weight of the pre-ferment, or the phrase "all of the _____from above" (fill in the blank). Listing pre-fermented flour weight and pre-ferment hydration, at a glance you can can calculate the total percentage flour contribution of the pre-fermented flour and any of the same flour added to the final dough.

I've built a spread sheet where in I only need enter pre-ferment weight, and hydration, and my desired final dough weight and hydration. The spreadsheet calculates the pre-fermented flour and water contributions; and the needed flour, water, and salt (assuming 2%) additions. Then I can enter the weights of individual flours, soakers, fats, etc. and liquids until there total weights and hydration match the desired dough weight, and hydration. It also calculates and shows a running percentage of each flour's percentage contribution. Doing so, building a 40% rye, with walnuts and a rye berry soaker, for example, is...I almost said "a piece of cake".

David G

Pop N Fresh's picture
Pop N Fresh



Can you share your spread sheet with us?  Sounds as if it can be very useful.





davidg618's picture

(That's my wife's website,) 

There are three Excel spread sheets: two for creating bread formulae (one in metric, one in oz.).

A third spreadsheet is for a fussy but effective way of building a formula-ready levain from a very small amount of seed starter, at any hydration, in 24 hours or less, using a three-build approach.I know there are easier ways, that take a third to half less time, but this way has never failed to provide a vigorously active levain, and allows me to store small amounts of seed starter. Here is the link to my TFL blog write up

The spreadsheets are protected to prevent inadvertently entering data into a wrong box, and destroying its formula content. However, there is no password invoked so you can change anything you wish to make it yours.

I recently found another minor mistake in the notes: The amount of salt needed is calculated as 2% of the Total Flour Weight , not the Total Dough Weight as stated. I haven't fixed it yet,

I just checked the link; it works, but I haven't visited it in months. Unlike what it says, I have updated the Ounce Formula spreadsheet,

David G


Pop N Fresh's picture
Pop N Fresh

Thank you David.   Very Helpful.

Love the breads at your Wife's site!

mlucas's picture

Thanks for the spreadsheets David, they look extremely useful. I also appreciated the link to the blog thread, as I think sometimes I'm a little lax in making sure the starter/levain is as active as possible before baking. e.g. multiplying my seed starter by four to get the needed amount for the recipe, in one step and directly out of the fridge too.

For my next bakes I think I will concentrate on improving the starter activity first, as much as I can with schedule. It can be difficult when you're away from home, at work or wherever! But with a little planning, taking the starter out of the fridge 12-24 hours earlier, it can certainly be done.

davidg618's picture

combining artisanal baking with work schedules. I'll be the first to admit much of the reason I can do these fussy things is I have the time. Nonetheless, I do think successful sourdoughs especially want a vigorous levain, and I don't think that can always be reached from refrigerator to formula in one massive feeding.

Good baking,

David G