Sourdough Starter Feeding Ratio Calculators

By Rebekah Parr | Published on September 17, 2024 | Updated on March 2, 2025

I’m horrible at math, so I created two sourdough starter calculators. I figured I would make them available here on my blog in case you need them, too!

Sourdough Starter Ratio Calculators

The first calculator allows you to enter how much starter you need, and you can choose your own feeding ratio.

The second calculator is for those who don’t really know what feeding ratio to use. Just choose when you want your starter to be ready to bake with, and the calculator will suggest the amount of starter, flour, and water to use.

If you want to learn ALL the details about feeding ratios – what they are, what the numbers mean, how you can use them to your advantage – check out this guide: The Ultimate Guide to Sourdough Starter Feeding Ratios

P.S.: I have another calculator to help with baker’s percentages and hydration level if you need it. Find it here: Sourdough Baker’s Percentage & Hydration Level Calculator

Sourdough Starter Feeding Ratio Calculator

Here’s a calculator to help you figure out how much starter, flour, and water to use with your desired feeding ratio:

Results:

How to use this calculator:

  1. In the first box, type how many grams of starter you want to make. This can be any number, based on your recipe.
  2. In the second through fourth boxes, input the ratio you want to use, like 1 to 1 to 1 (equal parts starter, flour, and water) or another ratio like 1 to 5 to 5 (1 part starter, 5 parts flour, 5 parts water). Experiment with different ratios for different peak windows. A 1:5:5 is my favorite ratio – I do this morning and night!
  3. Click ‘Calculate’. The calculator will show you exactly how much starter, flour, and water you need in grams to make the total starter amount you entered.

Useful material: Is My Sourdough Starter Ready to Bake With? How I Can Tell

Sourdough Starter Feeding Ratio Calculator (Select Your Timeframe)

If you have no clue what feeding ratio you want, this calculator lets you choose how far in the future you want your start to peak.

If you want your starter to be ready in 7 hours, as an example, select the 6-8 hour option. The calculator automatically picks the right feeding ratio for you and lets you know how much starter, flour, and water to use.

Results:


Fine print: this calculator makes assumptions based on averages for a 75°F/24°C home. You may need to adjust up or down based on your lived experience or if your home is warmer or cooler than mine. The strength of your starter will also greatly impact these averages.
The calculations used are as follows: 1:1:1 – 4 to 6 hours, 1:2:2 – 6 to 8 hours, 1:3:3 – 8 to 10 hours, 1:4:4 – 10 to 12 hours, 1:5:5 – 12 to 14 hours, and 1:10:10 – 16 to 24 hours.

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102 Comments

  1. I can’t thank you enough for this article and the calculators!!!! I am pretty new to Sourdough I only started in March and so far I’m obsessed but following you has made this journey even more excitable and less fearful so thank you very much!

  2. Thank You , this is so helpful. My starter became weak after sitting in the frig for weeks so in panic mode i found a new starter and using your info will have enough starter when its baking time again. Hoping to salvage the old starter but going to read and devour what and how first. Thanks Again, very much appreciated

  3. This calculator has been a real life saver for me. I have done many of your recipes and ALL have been successful. My sourdough baking, however, has been hit and miss lately. Sooooo disappointing. So I’m going to be trying Extra-Tangy Sourdough Bread which makes 2 loaves. What I really like is to make one loaf and have it turn out great. There are so many recipes for 2 loaves and not many for one. Wish me luck and I’ll let you know how it goes.

    Many thanks,

  4. Okay I am totally lost, I have 40 grams of starter in my refrigerator. I want to feed it and have more starter to work from so I can make a bulk batch of dough to keep in my refrigerator to pull out as needed. The starter I have came from my cousin and has been fed with a on 1 – 5-5 feeding. Do I take all 40 g and try to do it at once or do I take a smaller percentage say 10 g and add 50 g of water and 50 g of flour?

    1. Just take 10g from the 40 you have in the fridge and feed it 50g flour, 50g water. Once per day. It should perk back up and start doubling and hopefully tripling when it’s back at full strength.

  5. I just started my weekend baking and selling to my neighbors. I’ve been searching all over the Internet for this information. This calculator is amazing! Can it really be this easy? Thank you thank you!

      1. I had a difficult time trusting for my first time using the calculator method. I needed 600 grams of starter (6 loaves) so I overshot and put 700 grams of starter. I also used the 2nd calculator. After 12 hours, my starter had more than doubled. It was ready. Yet, I had only a smidge over 600 grams of starter. I’m wondering if I let the starter rise a little while longer, I would have gotten the 700 grams. I left it in my microwave overnight and my house was probably at a temp of lower to mid-70s. Any suggestions?

  6. Do you use stiff starter? If so what ratio of SS use to make liquid starter? Also what do you do to the SS discard?

    1. I maintain a liquid starter and make stiff sweet starters on occasion for a specific recipe. I therefore do not discard stiff starter since I’m making a specific amount for a specific recipe (this is called a levain).

  7. Hi there new to sour dough I like to follow a 1-4-4 ration and would like to have 200 gr of starter and 25 gr left over but I don’t see where to put in the details

  8. Thank you so much for this…. You should make this an app. I would absolutely buy it to have it on my phone at hand all the time.

  9. Hi Rebekah,
    I would first like to say, thank you so much for all your videos and especially the free recipes you share. I have really learned so much from you! I love the starter ratio calculator you created but am a little confused. I entered the amount needed (250 grams starter) and then I selected the feeding ratio’s (1:1:1) and the calculation came to 83 grams for each. I then used the time calculator and entered the amount of starter needed (250 grams) and selected 10-12 hours and the calculation came to 28 grams starter:111 grams water:111 grams flour. My confusion is that the recipe I plan to use is your Same-Day Sourdough Bread and your directions say to make the starter using 100 grams starter and 100 grams each of water and flour. Shouldn’t the calculators have given the same amount that the recipe does or am I entering something incorrectly?
    I hope you can help me figure this out.
    Thanks, Julia

    1. The ratio is different in the second calculator because you chose 10-12 hours for the timing, which requires a higher feeding ratio. We do a 1:1:1 feeding ratio in the same-day recipe so the starter rises really fast!

      1. Thank you, that makes sense! I appreciate you taking the time to explain it to me. I’m still learning about the ratios and how that, plus time, effects the starter. So interesting!

        1. Any time. I didn’t know what this was until about 6 months into making sourdough so don’t worry too much about it. The knowledge comes with time – in the meantime, we just flail around and try to make decent bread and learn from each failure! 🙂

  10. I used the second calculator last night to prepare for mixing today. I did build in extra to have leftover, but for comfort reasons, I’ll add in a little more next time. I’m still new to sourdough (4th week) and it was a little too close for comfort. lol

    Question. I’m still confused/struggling with leftover starter for the refrigerator. I only bake bread once a week, so leaving it on the counter and feeding it daily isn’t something that interests me. Do I feed the leftover when it goes back in the fridge? If yes, what ratio? And then, when I want to wake it up, I do the measurements to feed again, right? I’m just trying to get the sequence right in my head.

    Thanks so much! Your calculators were a stoke of genius!!

  11. My starter sits in my fridge, is this time frame calculator accurate if I’m starting to feed it again? Like say I want to do dough tonight, do I just follow the second calculator? Or do I still need to do a 1:1:1 for the first day and then feed it again the next day for dough? Idk if this makes sense 😂

    1. Haha, you want to wake up your starter if it has been in the fridge. Do a 1:5:5 feeding the day before you plan to feed it for a recipe. That extra feed should perk it back up and the time suggestions will be more spot on. It can take a little longer to rise if it has been in the fridge for a week or more.