How Much Fire Glass Do I Need?

Wondering how many jars of fire glass you need for your outdoor fire pit or fireplace? Buy too many, and you’ll have spent money unnecessarily. But if you fall short, you won’t have enough fire glass coverage to deliver that rich, shimmery shine.

We don’t want to leave you guessing, so here’s the scoop:

You’ll want enough fire glass in your fire pit to cover up the burner, which shouldn’t be visible. Aim for a depth of about 1/2″ of fire glass on top of the burner.

We’ve created the Celestial Fire Glass Calculator to eliminate guesswork and help you figure out exactly how much fire glass you need for your fire feature. The beauty of this simple online tool is that you can use it no matter the style of your fire feature: round, square, rectangular, or bowl-shaped. We’ve even provided a calculator for a fireplace.

Round Fire Pit

Round Fire Pit Calculator

Diameter (A) Inches:
Glass Depth (B) Inches:
Square/Rectangular Fire Pit

Square/Rectangular Fire Pit Calculator

Width (A) Inches:
Length (B) Inches:
Glass Depth (C) Inches:
Round Fire Bowl

Fire Bowl Calculator

Diameter (A) Inches:
Glass Depth (B) Inches:

Fireplace Calculator

Front Width (A) Inches:
Back Width (B) Inches:
Fireplace Depth (C) Inches:
Glass Depth (D) Inches:


Some rules of thumb to follow

Here are some handy tips to keep in mind when you’re doing your calculations and deciding how much fire pit glass to order:

  • Always stay on the conservative side with your initial order. Celestial Fire Glass ships its glass FAST via USPS Priority Mail — and best of all, it’s FREE! You can always add more fire glass later if you need to, and get it at your doorstep within 2 to 3 days. Believe us, that is easier and cheaper than shipping back heavy jars of fire glass if you’ve overbought!
  • Want to save money? Try filling the space beneath your fire pit burner with (unused) lava rocks. This is a cost-effective hack that’s especially useful if you have a large, custom-built fire pit with a sizeable open space under the burner.

If you have a standard-size fire pit, chances are the space under your burner isn’t very big and you probably won’t need a filler (since it wouldn’t save you much money anyway). You can check out the space below your burner and decide for yourself if this is something you should do. You can use our fire glass calculator to determine the amount of savings by using a filler. In cases where the savings is minimal we recommend going with the fire glass to the full depth.

What About Mixing Colors?

If you’re coming up short when filling your fire pit — and you have a couple of stored jars of Celestial Fire Glass in another color — don’t be afraid to mix it up! You can blend the pieces completely or lay the colors side by side. Use your creativity and have fun.

Keep It Clean

Fire glass, by its nature, is very low maintenance. But now and then, giving it a good cleaning can help it maintain its gorgeous luster. Cleaning your fire pit glass is a snap! Here are step-by-step instructions.

Ready to make the leap to a more dazzling fire pit display? From crushed fire glass to fire glass diamonds, we’ve got what you need to light up the night. Look for your perfect fire pit glass style and color now.