Sourdough Starter Calculator: 3 Easy Steps To Bulk Up Your Starter

Sourdough starter calculator—a total lifesaver when your recipe calls for more starter than you’ve actually got.

Now listen, I like math… but not when I’m preheating the oven, dealing with kids, and running low on coffee. You’ve got your bubbly starter sitting on the counter (or maybe quietly chilling in the fridge), and just when you’re ready to bake—bam! You realize you’re short.

Yep, been there—more than once.

Whether you’re prepping for a big bake day or just didn’t plan ahead like me, running low on starter can throw off your groove. But don’t stress—I’ve got just the thing to help: my Sourdough Starter Calculator.

What Is a Sourdough Starter Calculator, Anyway?

It’s your new best friend when it comes to starter math. The sourdough starter calculator is a simple, handy tool that helps you scale up or adjust your starter amounts based on your recipe needs. No more scrap paper, scribbles, or guessing if you’re feeding at the right ratio. Just plug in your numbers, pick a ratio, and boom—you’re golden.

Why You Might Need to Bulk Up Your Starter

Let’s be real, life gets busy. Here are a few common reasons you might find yourself needing a sourdough starter calculator:

You forgot to prep your starter ahead of time like me.
Your starter jar is running low, but your recipe calls for 200g, and you’ve only got 50g.
You want to avoid doing math when you haven’t even had coffee yet.
You’re testing new recipes and trying out different feeding ratios.

No matter the reason, having this tool in your sourdough toolkit is a total game-changer.

Understanding Feeding Ratios

Feeding ratios are one of those things that sound complicated until you break it down. A 1:1:1 ratio means equal parts starter, water, and flour. A 1:2:2 ratio means for every gram of starter, you feed it twice as much water and flour. And then there are big builds, like 1:10:10—great for prepping a large amount of active starter or for slowing things down a bit

Each ratio affects your starter differently. More food means slower fermentation, less tang, and more flexibility in timing. Less food means faster fermentation, more tangy flavor, and a starter that needs attention sooner.

The sourdough starter calculator helps you adjust easily, so you don’t have to worry if your math is off or if your dough will be underfed (or overfed).

So… What’s the Deal With Hydration?

Let’s talk hydration for a sec. This is the ratio of water to flour in your starter—and it matters.

High hydration (like 100%) = loose, bubbly starter = airy, open-crumb bread.
Low hydration (like 60%) means a thicker starter, which means a tighter crumb and easier handling. This is especially true for stiff starter formulas.

The sourdough starter calculator doesn’t just tell you how much flour and water to use—it also gives you the hydration percentage, so you know exactly what kind of dough you’re working with. Because baking is science… delicious, crusty science.

How to Use the Sourdough Starter Calculator

Here’s the quick-and-easy process:

• Enter how much starter you currently have.
• Input how much starter your recipe requires.
• Choose your desired feeding ratio—whether it’s 1:1:1, 1:2:2, 1:5:5, or even a stiff starter build.
• Hit calculate.
• Get your exact flour and water measurements, plus the hydration breakdown.
• No guesswork. No math spirals. Just confidence in your sourdough game.

Quick Example Time!

Let’s say you’ve got 50g of starter, and your recipe calls for 200g. If you select a 1:2:2 ratio, the sourdough starter calculator will do the math for you and tell you exactly how much flour and water to add—so you can hit that 200g target without overbuilding or wasting ingredients.

Ready to Level Up Your Baking Game?

If you’re loving tips like this, don’t forget to bookmark this page and share it with your fellow sourdough nerds. Better yet, sign up for my mailing list and get exclusive recipes, starter care tips, and baking freebies delivered straight to your inbox.

The sourdough starter calculator is just one of many tools I’ve created to help home bakers feel more confident and less stressed in the kitchen. So go ahead—feed that starter, preheat that oven, and get ready to bake something amazing.

Happy feeding, happy baking, and may your crust always crackle in the best way.

And hey — if you love tips, calculators, and easy-to-follow baking hacks like this, don’t forget to join my mailing list! You’ll get exclusive recipes, sourdough tricks, and subscriber-only goodies straight to your inbox.