EC To TDS Calculator: Convert EC To TDS (+3 Conversion Charts)

Before we got a TDS EC meter, we had to convert EC measurement to TDS manually. Well, we figured it would be easier to create an automatic EC to TDS calculator and 3 conversion charts, so that’s what we did, and that’s what we will share with you all.

Now, here is how this usually works:

We measure EC (Electrical Conductivity) in terms of µS/cm (these are microsiemens per centimeter, the basic unit all EC meters use. From this, we want to calculate TDS (Total Dissolved Solids) in terms of PPMs (Parts Per Million). By the way, the new TDS EC meter does the conversion automatically.

How can you convert EC to TDS?

If we really want to help everybody, we need to point out that we have 3 different PPM scales (US uses a 500 PPM scale, Europeans and international countries use a 640 PPM scale, and Australians have their own thing going with a 700 PPM scale). That’s why we get different TDS results.

We have accounted for these PPM scale differences in our EC to TDS calculator. Below the calculator, we explain how to do the math as well, and, most importantly, we include 3 EC to TDS conversion charts for all 3 PPM scales.

Basically, we took 1-1000 EC measurements, converted them to TDS (PPMs), and summarized the results in these 3 charts (quite useful, we also added a bit of color so that they look nice).

Here is the calculator you can freely use, followed by these charts:

 

Alright, let’s solve one example to see how this calculator works:

How many TDS is 100 EC? We use the US PPM scale in our lab. To figure that out, just slider the EC slider in the calculator to ‘100’, pick ‘United States Of America’, and you get this result right away (screenshot):

converting 100 ec to tds with an online calculator

You can see that, if we use the US 500 PPM scale, 100 TDS is equal to 50 TDS. In terms of units, that means that 100 µS/cm is equal to 50 PPM.

By the way, if you need to do the reverse calculation, you can use this EC to TDS calculator.

Before we check out the 3 charts, let’s have a quick look at the math behind this conversion:

How To Convert EC To TDS? (Math Formulas)

This conversion is fairly easy, we just need to be aware of those 3 different PPM scales. Here are the EC to TDS relationships for all different PPM scales:

US 500 PPM Scale: 1 EC = 0.5 TDS

European, International 640 PPM Scale: 1 EC = 0.64 TDS

Australian 700 PPM Scale: 1 EC = 0.7 TDS

We can rewrite these relationships to get EC to TDS formulas like this:

US Formula: TDS = EC × 0.5

Europe/International Formula: TDS = EC × 0.64

Australian Formula: TDS = EC × 0.7

Basically, to get TDS (in terms of PPMs), we need to multiply EC (µS/cm) by 0.5 if we are using the US scale, by 0.64 if we are using European/international scale, and Aussies just multiply the EC by 0.7 factor to get TDS.

Let’s solve another example just for fun:

How many TDS is 50 EC?

Let’s just insert ’50 EC’ into the equations like this (with results):

US: TDS (50 EC) = 50 EC × 0.5 = 25 TDS (PPM)

Europe/International: TDS (50 EC) = 50 EC × 0.64 = 32 TDS (PPM)

Australian: TDS (50 EC) = 50 EC × 0.7 = 35 TDS (PPM)

We can clearly see that 50 EC is equal to 25 TDS, 32 TDS, and 35 TDS for the US, European/international, and Australian PPM scales, respectively.

Now, the easiest way to convert EC to TDS – without the math or even the calculator – is just to read it off a conversion chart.

Here are all 3 conversion charts, starting with the 1st US chart, and followed by the European/international chart and Aussie chart:

1. EC To TDS Chart (US 500 PPM Scale)

In the US, we use a 500 PPM scale. Here are the conversions:

EC Or Electrical Conductivity (µS/cm): TDS In Terms Of PPM (US 500 PPM Scale):
1 EC (µS/cm) 0.5 TDS (PPM)
2 EC (µS/cm) 1 TDS (PPM)
3 EC (µS/cm) 1.5 TDS (PPM)
4 EC (µS/cm) 2 TDS (PPM)
5 EC (µS/cm) 2.5 TDS (PPM)
6 EC (µS/cm) 3 TDS (PPM)
7 EC (µS/cm) 3.5 TDS (PPM)
8 EC (µS/cm) 4 TDS (PPM)
9 EC (µS/cm) 4.5 TDS (PPM)
10 EC (µS/cm) 5 TDS (PPM)
15 EC (µS/cm) 7.5 TDS (PPM)
20 EC (µS/cm) 10 TDS (PPM)
25 EC (µS/cm) 12.5 TDS (PPM)
30 EC (µS/cm) 15 TDS (PPM)
35 EC (µS/cm) 17.5 TDS (PPM)
40 EC (µS/cm) 20 TDS (PPM)
45 EC (µS/cm) 22.5 TDS (PPM)
50 EC (µS/cm) 25 TDS (PPM)
55 EC (µS/cm) 27.5 TDS (PPM)
60 EC (µS/cm) 30 TDS (PPM)
65 EC (µS/cm) 32.5 TDS (PPM)
70 EC (µS/cm) 35 TDS (PPM)
75 EC (µS/cm) 37.5 TDS (PPM)
80 EC (µS/cm) 40 TDS (PPM)
85 EC (µS/cm) 42.5 TDS (PPM)
90 EC (µS/cm) 45 TDS (PPM)
95 EC (µS/cm) 47.5 TDS (PPM)
100 EC (µS/cm) 50 TDS (PPM)
110 EC (µS/cm) 55 TDS (PPM)
120 EC (µS/cm) 60 TDS (PPM)
130 EC (µS/cm) 65 TDS (PPM)
140 EC (µS/cm) 70 TDS (PPM)
150 EC (µS/cm) 75 TDS (PPM)
160 EC (µS/cm) 80 TDS (PPM)
170 EC (µS/cm) 85 TDS (PPM)
180 EC (µS/cm) 90 TDS (PPM)
190 EC (µS/cm) 95 TDS (PPM)
200 EC (µS/cm) 100 TDS (PPM)
210 EC (µS/cm) 105 TDS (PPM)
220 EC (µS/cm) 110 TDS (PPM)
230 EC (µS/cm) 115 TDS (PPM)
240 EC (µS/cm) 120 TDS (PPM)
250 EC (µS/cm) 125 TDS (PPM)
260 EC (µS/cm) 130 TDS (PPM)
270 EC (µS/cm) 135 TDS (PPM)
280 EC (µS/cm) 140 TDS (PPM)
290 EC (µS/cm) 145 TDS (PPM)
300 EC (µS/cm) 150 TDS (PPM)
310 EC (µS/cm) 155 TDS (PPM)
320 EC (µS/cm) 160 TDS (PPM)
330 EC (µS/cm) 165 TDS (PPM)
340 EC (µS/cm) 170 TDS (PPM)
350 EC (µS/cm) 175 TDS (PPM)
360 EC (µS/cm) 180 TDS (PPM)
370 EC (µS/cm) 185 TDS (PPM)
380 EC (µS/cm) 190 TDS (PPM)
390 EC (µS/cm) 195 TDS (PPM)
400 EC (µS/cm) 200 TDS (PPM)
410 EC (µS/cm) 205 TDS (PPM)
420 EC (µS/cm) 210 TDS (PPM)
430 EC (µS/cm) 215 TDS (PPM)
440EC (µS/cm) 220 TDS (PPM)
450 EC (µS/cm) 225 TDS (PPM)
460 EC (µS/cm) 230 TDS (PPM)
470 EC (µS/cm) 235 TDS (PPM)
480 EC (µS/cm) 240 TDS (PPM)
490 EC (µS/cm) 245 TDS (PPM)
500 EC (µS/cm) 250 TDS (PPM)
550 EC (µS/cm) 275 TDS (PPM)
600 EC (µS/cm) 300 TDS (PPM)
650 EC (µS/cm) 325 TDS (PPM)
700 EC (µS/cm) 350 TDS (PPM)
750 EC (µS/cm) 375 TDS (PPM)
800 EC (µS/cm) 400 TDS (PPM)
850 EC (µS/cm) 425 TDS (PPM)
900 EC (µS/cm) 450 TDS (PPM)
950 EC (µS/cm) 475 TDS (PPM)
1000 EC (µS/cm) 500 TDS (PPM)

2. EC To TDS Chart (European, International 640 PPM Scale)

In Europe and most of the world (internationally), we use a 640 PPM scale. Here is the full conversion chart:

EC Or Electrical Conductivity (µS/cm): TDS In Terms Of PPM (European, International 640 PPM Scale):
1 EC (µS/cm) 0.64 TDS (PPM)
2 EC (µS/cm) 1.28 TDS (PPM)
3 EC (µS/cm) 1.92 TDS (PPM)
4 EC (µS/cm) 2.56 TDS (PPM)
5 EC (µS/cm) 3.20 TDS (PPM)
6 EC (µS/cm) 3.84 TDS (PPM)
7 EC (µS/cm) 4.48 TDS (PPM)
8 EC (µS/cm) 5.12 TDS (PPM)
9 EC (µS/cm) 5.76 TDS (PPM)
10 EC (µS/cm) 6.40 TDS (PPM)
15 EC (µS/cm) 9.60 TDS (PPM)
20 EC (µS/cm) 12.80 TDS (PPM)
25 EC (µS/cm) 16.00 TDS (PPM)
30 EC (µS/cm) 19.20 TDS (PPM)
35 EC (µS/cm) 22.40 TDS (PPM)
40 EC (µS/cm) 25.60 TDS (PPM)
45 EC (µS/cm) 28.80 TDS (PPM)
50 EC (µS/cm) 32.00 TDS (PPM)
55 EC (µS/cm) 35.20 TDS (PPM)
60 EC (µS/cm) 38.40 TDS (PPM)
65 EC (µS/cm) 41.60 TDS (PPM)
70 EC (µS/cm) 44.80 TDS (PPM)
75 EC (µS/cm) 48.00 TDS (PPM)
80 EC (µS/cm) 51.20 TDS (PPM)
85 EC (µS/cm) 54.40 TDS (PPM)
90 EC (µS/cm) 57.60 TDS (PPM)
95 EC (µS/cm) 60.80 TDS (PPM)
100 EC (µS/cm) 67.20 TDS (PPM)
110 EC (µS/cm) 70.40 TDS (PPM)
120 EC (µS/cm) 76.80 TDS (PPM)
130 EC (µS/cm) 83.20 TDS (PPM)
140 EC (µS/cm) 89.60 TDS (PPM)
150 EC (µS/cm) 96.00 TDS (PPM)
160 EC (µS/cm) 102.40 TDS (PPM)
170 EC (µS/cm) 108.80 TDS (PPM)
180 EC (µS/cm) 115.20 TDS (PPM)
190 EC (µS/cm) 121.60 TDS (PPM)
200 EC (µS/cm) 128.00 TDS (PPM)
210 EC (µS/cm) 134.40 TDS (PPM)
220 EC (µS/cm) 140.80 TDS (PPM)
230 EC (µS/cm) 147.20 TDS (PPM)
240 EC (µS/cm) 153.60 TDS (PPM)
250 EC (µS/cm) 160.00 TDS (PPM)
260 EC (µS/cm) 166.40 TDS (PPM)
270 EC (µS/cm) 172.80 TDS (PPM)
280 EC (µS/cm) 179.20 TDS (PPM)
290 EC (µS/cm) 185.60 TDS (PPM)
300 EC (µS/cm) 192.00 TDS (PPM)
310 EC (µS/cm) 198.40 TDS (PPM)
320 EC (µS/cm) 204.80 TDS (PPM)
330 EC (µS/cm) 211.20 TDS (PPM)
340 EC (µS/cm) 217.60 TDS (PPM)
350 EC (µS/cm) 224.00 TDS (PPM)
360 EC (µS/cm) 230.40 TDS (PPM)
370 EC (µS/cm) 236.80 TDS (PPM)
380 EC (µS/cm) 243.20 TDS (PPM)
390 EC (µS/cm) 249.60 TDS (PPM)
400 EC (µS/cm) 256.00 TDS (PPM)
410 EC (µS/cm) 262.40 TDS (PPM)
420 EC (µS/cm) 268.80 TDS (PPM)
430 EC (µS/cm) 275.20 TDS (PPM)
440 EC (µS/cm) 281.60 TDS (PPM)
450 EC (µS/cm) 288.00 TDS (PPM)
460 EC (µS/cm) 294.40 TDS (PPM)
470 EC (µS/cm) 300.80 TDS (PPM)
480 EC (µS/cm) 307.20 TDS (PPM)
490 EC (µS/cm) 313.60 TDS (PPM)
500 EC (µS/cm) 320.00 TDS (PPM)
550 EC (µS/cm) 352.00 TDS (PPM)
600 EC (µS/cm) 384.00 TDS (PPM)
650 EC (µS/cm) 416.00 TDS (PPM)
700 EC (µS/cm) 448.00 TDS (PPM)
750 EC (µS/cm) 480.00 TDS (PPM)
800 EC (µS/cm) 512.00 TDS (PPM)
850 EC (µS/cm) 544.00 TDS (PPM)
900 EC (µS/cm) 576.00 TDS (PPM)
950 EC (µS/cm) 608.00 TDS (PPM)
1000 EC (µS/cm) 640.00 TDS (PPM)

3. EC To TDS Chart (Australian 700 PPM Scale)

In Australia, we use a 700 PPM scale. Here is the resulting EC to TDS conversion chart:

EC Or Electrical Conductivity (µS/cm): TDS In Terms Of PPM (Australian 700 PPM Scale):
1 EC (µS/cm) 0.7 TDS (PPM)
2 EC (µS/cm) 1.4 TDS (PPM)
3 EC (µS/cm) 2.1 TDS (PPM)
4 EC (µS/cm) 2.8 TDS (PPM)
5 EC (µS/cm) 3.5 TDS (PPM)
6 EC (µS/cm) 4.2 TDS (PPM)
7 EC (µS/cm) 4.9 TDS (PPM)
8 EC (µS/cm) 5.6 TDS (PPM)
9 EC (µS/cm) 6.3 TDS (PPM)
10 EC (µS/cm) 7 TDS (PPM)
15 EC (µS/cm) 10.5 TDS (PPM)
20 EC (µS/cm) 14 TDS (PPM)
25 EC (µS/cm) 17.5 TDS (PPM)
30 EC (µS/cm) 21 TDS (PPM)
35 EC (µS/cm) 24.5 TDS (PPM)
40 EC (µS/cm) 28 TDS (PPM)
45 EC (µS/cm) 31.5 TDS (PPM)
50 EC (µS/cm) 35 TDS (PPM)
55 EC (µS/cm) 38.5 TDS (PPM)
60 EC (µS/cm) 42 TDS (PPM)
65 EC (µS/cm) 45.5 TDS (PPM)
70 EC (µS/cm) 49 TDS (PPM)
75 EC (µS/cm) 52.5 TDS (PPM)
80 EC (µS/cm) 56 TDS (PPM)
85 EC (µS/cm) 59.5 TDS (PPM)
90 EC (µS/cm) 63 TDS (PPM)
95 EC (µS/cm) 66.5 TDS (PPM)
100 EC (µS/cm) 70 TDS (PPM)
110 EC (µS/cm) 77 TDS (PPM)
120 EC (µS/cm) 84 TDS (PPM)
130 EC (µS/cm) 91 TDS (PPM)
140 EC (µS/cm) 98 TDS (PPM)
150 EC (µS/cm) 105 TDS (PPM)
160 EC (µS/cm) 112 TDS (PPM)
170 EC (µS/cm) 119 TDS (PPM)
180 EC (µS/cm) 126 TDS (PPM)
190 EC (µS/cm) 133 TDS (PPM)
200 EC (µS/cm) 140 TDS (PPM)
210 EC (µS/cm) 147 TDS (PPM)
220 EC (µS/cm) 154 TDS (PPM)
230 EC (µS/cm) 161 TDS (PPM)
240 EC (µS/cm) 168 TDS (PPM)
250 EC (µS/cm) 175 TDS (PPM)
260 EC (µS/cm) 182 TDS (PPM)
270 EC (µS/cm) 189 TDS (PPM)
280 EC (µS/cm) 196 TDS (PPM)
290 EC (µS/cm) 203 TDS (PPM)
300 EC (µS/cm) 210 TDS (PPM)
310 EC (µS/cm) 217 TDS (PPM)
320 EC (µS/cm) 224 TDS (PPM)
330 EC (µS/cm) 231 TDS (PPM)
340 EC (µS/cm) 238 TDS (PPM)
350 EC (µS/cm) 245 TDS (PPM)
360 EC (µS/cm) 252 TDS (PPM)
370 EC (µS/cm) 259 TDS (PPM)
380 EC (µS/cm) 266 TDS (PPM)
390 EC (µS/cm) 273 TDS (PPM)
400 EC (µS/cm) 280 TDS (PPM)
410 EC (µS/cm) 287 TDS (PPM)
420 EC (µS/cm) 294 TDS (PPM)
430 EC (µS/cm) 301 TDS (PPM)
440 EC (µS/cm) 308 TDS (PPM)
450 EC (µS/cm) 315 TDS (PPM)
460 EC (µS/cm) 322 TDS (PPM)
470 EC (µS/cm) 329 TDS (PPM)
480 EC (µS/cm) 336 TDS (PPM)
490 EC (µS/cm) 343 TDS (PPM)
500 EC (µS/cm) 350 TDS (PPM)
550 EC (µS/cm) 385 TDS (PPM)
600 EC (µS/cm) 420 TDS (PPM)
650 EC (µS/cm) 455 TDS (PPM)
700 EC (µS/cm) 490 TDS (PPM)
750 EC (µS/cm) 525 TDS (PPM)
800 EC (µS/cm) 560 TDS (PPM)
850 EC (µS/cm) 595 TDS (PPM)
900EC (µS/cm) 630 TDS (PPM)
950 EC (µS/cm) 665 TDS (PPM)
1000 EC (µS/cm) 700 TDS (PPM)

You have to admit; these charts make the EC to TDS conversion super easy. You can also use the Waternity Lab online calculator, or even convert this by hand. If you need a bit of help, we are always here for you; just use the comment section below, send us a few numbers, and we can do some math to help you out.

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