Sourdough Starter Calculators

Baking sourdough is a delightful mix of art and science - and a little bit of math.

If you're anything like me, you've probably found yourself trying to do mental math, or getting your phone screen sticky with your hands full of dough more than once.

So I created these sourdough starter calculators to help make your baking life easier, especially when you're scaling up recipes or timing things just right.

Jump to:

• Sourdough Starter Amount Calculator
• Sourdough Starter Feeding Ratio Calculator
• Sourdough Starter Feeding Timing Calculator

In this post, I'll share three handy calculators that take the mystery out of sourdough starter planning:

1. Sourdough Starter Amount Calculator - figure out exactly how much starter you need for any number of loaves.
2. Sourdough Starter Feeding Timing Calculator - if you already know what feeding ratio you would like to use, this calculator will help you determine the right amounts of starter, water and flour you will need to make that amount of starter without waste.
3. Sourdough Starter Feeding Ratio Calculator - if you know at what time you would like you starter to be ready, this calculator will help you determine what ratio to use and how much to feed your sourdough starter so your starter is peaking right when you're ready to mix the dough.

No complicated formulas or fancy apps required - just bookmark and come back to this page whenever you need to use the calculators.

Sourdough Starter Amount Calculator

How much starter do I need? This is the first question to answer before any big bake. If you're scaling a recipe up or baking multiple loaves at once, it's easy to second-guess yourself.

The sourdough starter amount calculator cuts through the confusion by telling you exactly how much sourdough starter you'll require in total.

Using it is straightforward:

• just enter how much starter your recipe calls for per loaf (in grams)
• and enter how many loaves you plan to bake

That's it! The calculator will do the simple multiplication for you - no ify mental math here.

For example, if you are using my classic sourdough bread recipe that uses 90 grams of starter for one loaf and you want to bake 2 loaves, you'll need 180 grams of starter in total.

Likewise, say you're planning a big bake for a market and you're aiming for 50 loaves, that's 4,500 g of starter you'll need to have on hand. (Yes, 4.5 kilos! Time to break out a really big bucket for that one).

With a precise total, you can feed and build only what you need. That saves flour, time, and a bit of your sanity.

Once you have your magic number - the total grams of starter needed - you can plan how to build it up. That brings us to the next tool: choosing the right feeding ratio to get to that amount efficiently.

Sourdough Starter Feeding Ratio Calculator

Now that you know how much starter you need, the next question is how to build it. This is where feeding ratios come into play.

A feeding ratio describes the proportion of starter, water, and flour you mix together when feeding. Changing the ratio changes two big things: how much starter you end up with, and how quickly it ferments and peaks.

But how do you decide what feeding ratio to use to feed your sourdough starter with?

The sourdough starter feeding ratio calculator lets you experiment with this. You just need to input:

• the total amount of starter you want (from the first calculator)
• and how far ahead of baking you want to feed

The calculator will tell you exactly what feeding ratio to use and how much existing starter to start with and how much flour and water to add for that feeding ratio. Boom!

Sourdough Starter Feeding Timing Calculator

Now, let's say you already know your preferred feeding ratio, but you just want to quickly calculate how much to feed your sourdough starter and when, so that it's at peak when you are ready to mix your dough.

The sourdough starter feeding timing calculator helps you figure this out easily. You just need to enter:

• the total amount of starter you need (from the first calculator)
• and select your preferred feeding ratio

It will tell you how much existing starter to start with and how much flour and water to add for that ratio, as well as an estimate of how many hours it will take to peak at room temperature (~72°F or 22°C).

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One more pro tip: always give your growing starter plenty of room. Use a large jar or container for your growing sourdough starter. A healthy one can easily double or triple in size - the last thing you want is a volcanic overflow on your counter because you crammed 400 grams of starter into a mason jar. (Ask me how I know… 😅)

If you have questions, please leave them below. Or if you want to show my blog a little love, please leave me a comment. You will make my day!