Grains per gallon to ppm CaCO₃
Type a value in gpg to get it in ppm instantly.
2,567.7ppm
That's 8.6× as hard as very hard water — nothing on our list beats it. That is very hard water: descaling becomes a regular chore.
Convert the other way: ppm to gpg
What it means
How hard is that water?
All scales measure the same thing, calcium carbonate content, just with different sized degrees.
The math
How to convert gpg to ppm
To convert grains per gallon to ppm CaCO₃, multiply by 17.118.
Example: 150 gpg × 17.118 = 2,567.7 ppm.
In the other direction, 1 ppm = 0.058418 gpg.
Every unit
Your hardness in every unit
Tables
gpg to ppm conversion table
| gpg | ppm |
|---|---|
| 20 gpg | 342.36 ppm |
| 40 gpg | 684.72 ppm |
| 60 gpg | 1,027.08 ppm |
| 80 gpg | 1,369.44 ppm |
| 100 gpg | 1,711.8 ppm |
| 120 gpg | 2,054.16 ppm |
| 150 gpg | 2,567.7 ppm |
| 180 gpg | 3,081.24 ppm |
| 200 gpg | 3,423.6 ppm |
| 250 gpg | 4,279.5 ppm |
| 300 gpg | 5,135.4 ppm |
| 400 gpg | 6,847.2 ppm |
ppm to gpg conversion table
| ppm | gpg |
|---|---|
| 20 ppm | 1.16836 gpg |
| 40 ppm | 2.33672 gpg |
| 60 ppm | 3.50508 gpg |
| 80 ppm | 4.67344 gpg |
| 100 ppm | 5.8418 gpg |
| 120 ppm | 7.01016 gpg |
| 150 ppm | 8.76271 gpg |
| 180 ppm | 10.5152 gpg |
| 200 ppm | 11.6836 gpg |
| 250 ppm | 14.6045 gpg |
| 300 ppm | 17.5254 gpg |
| 400 ppm | 23.3672 gpg |
Quick answers
Quick answers
- How many ppm is 1 gpg?
- 1 gpg is 17.118 ppm.
- How many ppm is 10 gpg?
- 10 gpg is 171.18 ppm.
- How many ppm is 150 gpg?
- 150 gpg is 2,567.7 ppm.
The units
About these units
Grains per gallon (gpg)
Grains of calcium carbonate per US gallon, the unit American water softeners are set in.
Ppm CaCO₃ (ppm)
Milligrams of calcium carbonate per liter, the unit on most water company reports.
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