We have many different units for water hardness. If you have water hardness expressed in **GPG** *( Grains Per Gallon)*, and you like to express it in terms of

**dH**(

*; same as*

**d**egrees of**H**ardness**dGH**or

*), you have to convert GPG to dH.*

**d**egrees of**G**eneral**H**ardnessTo make this conversion easier for everybody, we at Waternity Lab created an easy-to use calculator that ** converts GPG to dH** (same as GPG to dGH conversion) immediately.

Below the calculator, we also use 15 GPG to dH example to demonstrate how to use this calculator (we also do math-based 5 GPG to dH example).

On top of that, we explain the math behind the conversion, as well as feature a **conversion chart where we have converted 0.1 – 50 GPG to dH**, and summarized the result in a color-coded chart (color = water hardness categorization, more about this later on).

Here is the online GPG to dH calculator you can freely use:

Now, let’s look at that example: **How many dH is 15 GPG?**

You just slide the GPG slider to **‘15.0’**, and you get the result immediately in this form:

You can see right away that 15 GPG is equal to **14.39 dH** (or dGH, since this is the same unit).

Additionally, you can also see that water with a 15 GPG or 14.39 dH hardness is categorized as **“Very Hard”** water.

Let’s look at the math behind this conversion:

### How To Convert GPG To dH (dGH)?

Namely, we only need to know this 1 conversion relationship:

**1 dH = 0.9591 GPG**

This means that 1 dH is equal to 0.9591 GPG. Thus, we can write the GPG to dH conversion formula like this:

**dH = GPG Ã— 0.9591**

To calculate how many dH any number of grains per gallon (GPG) is, we have to multiply GPG by 0.9591.

Let’s solve this example with a bit of math: How many dH is 5 GPG? We just insert 5 GPG into the equation and calculate the resulting dH like this:

**dH (5 GPG) **= *5 GPG* Ã— 0.9591 = *4.80 dH*

We can see that 5 GPG is equal to 4.80 dH (or dGH, also known as “German” degrees). You can use the calculator above to confirm this; just slide the GPG slider to ‘5.0’.

Here is the conversion chart. This chart is color-coded, based on the water hardness categorization: **soft** water *(0 – 3.5 GPG)* is denoted with ** this green color**,

**moderately hard**water

*(3.56 – 7.01 GPG)*with this

**,**

*light blue color***hard**water

*(7.06 – 10.51 GPG)*with

**, and**

*this blue color***very hard**water

*(10.57+ GPG)*with

**Â as per water hardness scale seen here:**

*this dark blue color*### GPG To dH (dGH) Conversion Chart

GPG (Grains Per Gallon): |
dH or dGH (degrees of General Hardness): |

0.1 GPG | 0.10 dH |

0.2 GPG | 0.19 dH |

0.3 GPG | 0.29 dH |

0.4 GPG | 0.38 dH |

0.5 GPG | 0.48 dH |

0.6 GPG | 0.58 dH |

0.7 GPG | 0.67 dH |

0.8 GPG | 0.77 dH |

0.9 GPG | 0.86 dH |

1 GPG | 0.96 dH |

1.5 GPG | 1.44 dH |

2 GPG | 1.92 dH |

2.5 GPG | 2.40 dH |

3 GPG | 2.88 dH |

3.5 GPG | 3.36 dH |

4 GPG | 3.84 dH |

4.5 GPG | 4.32 dH |

5 GPG | 4.80 dH |

5.5 GPG | 5.28 dH |

6 GPG | 5.75 dH |

6.5 GPG | 6.23 dH |

7 GPG | 6.71 dH |

7.5 GPG | 7.19 dH |

8 GPG | 7.67 dH |

8.5 GPG | 8.15 dH |

9 GPG | 8.63 dH |

9.5 GPG | 9.11 dH |

10 GPG | 9.59 dH |

11 GPG | 10.55 dH |

12 GPG | 11.51 dH |

13 GPG | 12.47 dH |

14 GPG | 13.43 dH |

15 GPG | 14.39 dH |

16 GPG | 15.35 dH |

17 GPG | 16.30 dH |

18 GPG | 17.26 dH |

19 GPG | 18.22 dH |

20 GPG | 19.18 dH |

21 GPG | 20.14 dH |

22 GPG | 21.10 dH |

23 GPG | 22.06 dH |

24 GPG | 23.02 dH |

25 GPG | 23.98 dH |

26 GPG | 24.94 dH |

27 GPG | 25.90 dH |

28 GPG | 26.85 dH |

29 GPG | 27.81 dH |

30 GPG | 28.77 dH |

35 GPG | 33.57 dH |

40 GPG | 38.36 dH |

45 GPG | 43.16 dH |

50 GPG | 47.96 dH |

Based on this conversion chart, we can quickly see that (in accordance with the water hardness scale here):

**“Soft”**water has**0 – 3.5 GPG**orwater hardness.*0 – 3.36 dH***“Moderately Hard”**water has**3.6 – 7 GPG**orwater hardness.*3.37 – 6.71 dH***“Hard”**water has**7.5 – 10 GPG**orwater hardness.*6.72 – 9.59 dH***“Very Hard”**water has more than**10Â GPG**or more than**9.59**water hardness.*Â dH*

Hopefully, now you understand everything about the water hardness GPG to dH conversion. You can use the calculator, this chart, or even do the math yourself. If you need any help from us, you can use the comment section below, give us a few numbers, and we can do a bit of math for you.

Here are some similar calculators that might be helpful:

- GPG To mg/L CaCO3 Calculator.
- GPG To PPM Calculator.
- mg/L To dGH Calculator.
- PPM To dGH Calculator.
- PPM To GPG Calculator.

Thank you.