Alkalinity PPM To dKH Calculator: Convert PPM CaCO3 To dKH

dKH is a less common water hardness unit. dKH stands for degrees of Karbonathärte (or degrees of German Carbonate Hardness). In some cases, you will need to convert PPM to dKH. We will show you exactly how to convert PPM (Parts Per Million of CaCO3) to dKH. Here are 3 useful tools you will get:

  1. PPM to dKH Calculator. You insert PPM CaCO3 in the calculator, and get dKH equivalent right away. On top of that, the calculator also tells you if this inserted PPM / dKH water is considered “Soft”, “Moderately Hard”, “Hard”, or “Very Hard” water.
  2. PPM to dKH Formula. We look at the equation that converts between PPM and dkH (the math).
  3. PPM to dKH Conversion Chart. We converted 1-1000 PPM into dKH, and summarized all the results in a neat chart. The chart is also color-coded, based on the water hardness categorization: soft water (0 – 60 PPM) is denoted with this green color, moderately hard water (61 – 120 PPM) with this light blue color, hard water (121 – 180 PPM) with this blue color, and very hard water (181+ PPM) with this dark blue color.

Quick Example: In the photo above, you can see we measured 165 PPM water hardness with a TDS meter. Using the PPM to dKH calculator below, we quickly calculate that 165 PPM is equal to 9.24 dKH.

Let’s start with the calculator, and then we will look at the formula and the conversion chart:


Let’s solve one example here just to illustrate how this online PPM to dKH calculator works:

How many dKH is 150 PPM? Just slide the PPM slider to ‘150’, and you get this result (screenshot):

using calculator to convert ppm to dkh degrees of carbonate hardness

You can quickly see that 150 PPM is equal to 8.40 dKH. On top of that, you can also see that this is considered “Hard” water, in accordance with the water hardness scale here.

If you need to make this conversion in reverse – converting dKH to PPM – you should check a similar dKH to PPM calculator here.

Let’s look at the math behind this conversion:

PPM To dKH Formula

Here is the PPM to dKH formula:

dKH = PPM / 17.848

Namely, if we want to convert PPM to dKH, we need to divide PPMs by 17.848 to get dKH or degrees of Carbonate Hardness.

Here is this formula in action:

How many dKH is 200 PPM?

We simply insert 200 PPM in the equation above like this (with the result):

dKH (200 PPM) = 200 PPM / 17.848 = 11.21 dKH

We see that 200 PPM is equal to 11.21 dKH (this is categorized as “Very Hard” water, by the way).

This is just 1 example. We converted 1-1000 PPM to dKH, and summarized all the results in the following color-coded conversion chart:

PPM To dKH Chart

PPM (Parts Per Million): dKH (degrees of Carbonate Hardness):
1 PPM 0.06 dKH
5 PPM 0.28 dKH
10 PPM 0.56 dKH
15 PPM 0.84 dKH
20 PPM 1.12 dKH
25 PPM 1.40 dKH
30 PPM 1.68 dKH
35 PPM 1.96 dKH
40 PPM 2.24 dKH
45 PPM 2.52 dKH
50 PPM 2.80 dKH
60 PPM 3.36 dKH
70 PPM 3.92 dKH
80 PPM 4.48 dKH
90 PPM 5.04 dKH
100 PPM 5.60 dKH
110 PPM 6.16 dKH
120 PPM 6.72 dKH
130 PPM 7.28 dKH
140 PPM 7.84 dKH
150 PPM 8.40 dKH
160 PPM 8.96 dKH
170 PPM 9.52 dKH
180 PPM 10.09 dKH
190 PPM 10.65 dKH
200 PPM 11.21 dKH
250 PPM 14.01 dKH
300 PPM 16.81 dKH
350 PPM 19.61 dKH
400 PPM 22.41 dKH
450 PPM 25.21 dKH
500 PPM 28.01 dKH
550 PPM 30.82 dKH
600 PPM 33.62 dKH
650 PPM 36.42 dKH
700 PPM 39.22 dKH
750 PPM 42.02 dKH
800 PPM 44.82 dKH
850 PPM 47.62 dKH
900 PPM 50.43 dKH
950 PPM 53.23 dKH
1000 PPM 56.03 dKH

If you need to convert parts per million to degrees of carbonate hardness, you can just look at this chart. Based on the colors, we see that:

  • “Soft” water has 0 dKH to 3.36 dKH (equivalent to 0-60 PPM).
  • “Moderately Hard” water has 3.37 dKH to 6.72 dKH (equivalent to 61-120 PPM).
  • “Hard” water has 6.73 dKH to 10.09 dKH (equivalent to 121-180 PPM).
  • “Very Hard” water has more than 10.10 dKH (equivalent to more than 180 PPM).

Using the calculator and this chart, you are now fully equipped to convert PPM to dKH. If you need any help with this conversion, you can use the comment section below, give us a few numbers, and we can do some math for you. Thank you.

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