Concrete Calculator – How To Figure Ingredient Quantities

How to Calculate Amount of Portland Cement and
Other Ingredients for Garden Art Projects

I received an email the other day from Tess asking me:

Hi! We are going to try to make a 4 ft diameter millstone garden fountain out of hypertufa. I believe your recipe for the Hypertufa Recipe With Fiber Mesh for Added Strength is the way to go. Any idea how much of the ingredients we will need to get to accomplish this? Will this hold up with constant water and hard winters?

Thanks in advance, Tess

My reply:

Hi Tess:
About the quantity needed – here’s a nifty free concrete calculator on another website that you can use: concrete calculator.

In the “Round Footing” section, I filled in 4-feet 0-inches X 6-inches high and I got 9.4 80-lb bags required. So you fill in the calculator and see what result you get and then buy at least that much Portland cement. Then buy the rest of the ingredient(s) you want to use in proportion to the cement. **Better to have more on hand than needed – you can always return a bag of cement if it is unopened.

However, why are you making it in hypertufa, rather than a “pure” concrete recipe??? The peat moss will decompose over time, especially being that it will be in direct contact with water 24/7. Do you want small pits and crevices in your millstone, or do you want it to be more authentic looking like smooth stone? Don’t use a hypertufa recipe if you want a smoother stone.

Yes – your finished project, whether ‘tufa or ‘crete, *should* hold up to freezes and thaws for many many years, that is IF you concocted the recipe correctly and IF you allowed it to cure properly. I suggest you try your hand at a smaller project with the recipe you decide to use first … give it a month to cure and at least see if it holds together properly, etc. Then tackle the big millstone project. Better safe than sorry and wasting LOTS of product.

Best of luck with this project!


  1. I am definitely bookmarking this page and sharing it with my other friends. This will help alot with my next hypertufa project.

  2. To figure out how much concrete you need to order in case you don’t want do mix it by hand here’s a great link.

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