{"id":66776,"date":"2026-10-13T08:59:31","date_gmt":"2026-10-13T05:59:31","guid":{"rendered":"https:\/\/wpcalc.com\/en\/?p=66776"},"modified":"2026-10-13T08:59:31","modified_gmt":"2026-10-13T05:59:31","slug":"ec-to-tds-converter","status":"publish","type":"post","link":"https:\/\/wpcalc.com\/en\/converters\/ec-to-tds-converter\/","title":{"rendered":"EC to TDS Converter"},"content":{"rendered":"<section class=\"not-prose calculator-box\" aria-labelledby=\"calculator-title\"><div class=\"flex items-baseline sm:items-center justify-between gap-2 sm:gap-3\"><div class=\"flex flex-col sm:flex-row sm:items-center gap-2\"><span class=\"icon icon-calculator text-primary-700! text-base! dark:text-primary-300!\" aria-hidden=\"true\"><\/span><h2 id=\"calculator-title\" class=\"text-lg font-display font-bold\">Convert Conductivity to Total Dissolved Solids<\/h2><\/div><div class=\"calcdash-favorite group\">\n  <button type=\"button\" class=\"favorite\" id=\"favorite\" data-favorite-id=\"66776\" data-favorite-title=\"EC to TDS\" data-favorite-url=\"https:\/\/wpcalc.com\/en\/converters\/ec-to-tds-converter\/\" data-favorite-excerpt=\"Convert an electrical conductivity (EC) reading in \u00b5S\/cm, mS\/cm or S\/m into an estimated TDS value in ppm. Choose the conversion factor your meter uses (0.5, 0.64 or 0.7) and get an instant result.\" aria-label=\"Add to Favorites\" data-favorite-icon=\"icon icon-chemistry\">\n    <span class=\"icon icon-shape-star-empty\" aria-hidden=\"true\"><\/span>\n  <\/button>\n  <div class=\"calcdash-favorite__tip\" aria-hidden=\"true\">\n   <span class=\"favorite-tooltip\" id=\"favorite-tooltip\"><\/span>\n  <\/div>\n  <span class=\"sr-only\" role=\"status\" id=\"favorite-status\"><\/span>\n<\/div><\/div><form action=\"https:\/\/wpcalc.com\/en\/converters\/ec-to-tds-converter\/\" method=\"POST\" class=\"calculator\" id=\"calculator-66776\" data-post=\"66776\"><fieldset class=\"fieldset-input is-1\"><legend class=\"sr-only\">Input Fields<\/legend><div class=\"field\" id=\"input-1\"><label for=\"field-1\">Electrical conductivity (EC)<\/label><div class=\"field-group\"><input type=\"text\" name=\"electrical_conductivity_ec\" id=\"field-1\" aria-describedby=\"calc-info-1\" data-number inputmode=\"decimal\" autocomplete=\"off\" spellcheck=\"false\" min=\"0\" value=\"500\"\/><div class=\"grid grid-cols-1\"><select id=\"field-2\" name=\"unit\" aria-label=\"Unit\"><option value=\"us\" selected>\u00b5S\/cm<\/option><option value=\"ms\">mS\/cm<\/option><option value=\"sm\">S\/m<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><small id=\"calc-info-1\">Reading from your conductivity meter<\/small><\/div><div class=\"field\" id=\"input-2\"><label for=\"field-3\">TDS conversion factor<\/label><div class=\"grid grid-cols-1\"><select id=\"field-3\" name=\"tds_conversion_factor\"><option value=\"f500\" selected>0.5 \u2014 NaCl scale (500 ppm per mS\/cm)<\/option><option value=\"f640\">0.64 \u2014 KCl scale (640 ppm per mS\/cm)<\/option><option value=\"f700\">0.7 \u2014 natural water scale (700 ppm per mS\/cm)<\/option><\/select><svg class=\"pointer-events-none col-start-1 row-start-1 mr-2 size-5 self-center justify-self-end text-gray-500 sm:size-4\" viewBox=\"0 0 16 16\" fill=\"currentColor\" aria-hidden=\"true\" data-slot=\"icon\">\n              <path fill-rule=\"evenodd\" d=\"M4.22 6.22a.75.75 0 0 1 1.06 0L8 8.94l2.72-2.72a.75.75 0 1 1 1.06 1.06l-3.25 3.25a.75.75 0 0 1-1.06 0L4.22 7.28a.75.75 0 0 1 0-1.06Z\" clip-rule=\"evenodd\" \/>\n            <\/svg><\/div><\/div><\/fieldset><div class=\"buttons\"><button type=\"submit\" data-text=\"Re-Calculate\" id=\"calculate-button\" data-post=\"66776\">Calculate<\/button><button type=\"reset\">Reset<\/button><\/div><div class=\"field is-checkbox hidden!\" id=\"field-auto-calc\"><input type=\"checkbox\" id=\"auto-calc\"><label for=\"auto-calc\">Calculate automatically<\/label><small>If enabled, the result will update automatically when you change any value.<\/small><\/div><div class=\"fieldset-result is-hidden\" aria-labelledby=\"result-title\" aria-live=\"polite\" role=\"region\"> <h3 class=\"result-title bg-gradient-to-r from-primary-50 to-gray-50 dark:from-primary-900 dark:to-gray-800\" id=\"result-title\"><span class=\"icon icon-s-pulse\" aria-hidden=\"true\"><\/span> Estimated TDS<\/h3><div class=\"result-box\"><div class=\"field-result is-column\" id=\"output-1\"><span class=\"field-title\"><span>Total dissolved solids (TDS)<\/span><\/span><span class=\"field-value\" id=\"result-1\" data-unit=\"ppm (mg\/L)\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copy Result\" aria-label=\"Copy Result\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><div class=\"field-result is-column\" id=\"output-2\"><span class=\"field-title\"><span>Note<\/span><\/span><span class=\"field-value\" id=\"result-2\"><\/span><button type=\"button\" class=\"copy-result\" data-tooltip=\"Copy Result\" aria-label=\"Copy Result\"><span class=\"copy-icon icon icon-document-copy\" aria-hidden=\"true\"><\/span><\/button><\/div><\/div><div class=\"result-actions\"><button type=\"button\" class=\"copy-link\"><svg viewBox=\"0 0 20 20\" fill=\"currentColor\" aria-hidden=\"true\"><path d=\"M12.232 4.232a2.5 2.5 0 0 1 3.536 3.536l-1.225 1.224a.75.75 0 0 0 1.061 1.06l1.224-1.224a4 4 0 0 0-5.656-5.656l-3 3a4 4 0 0 0 .225 5.865.75.75 0 0 0 .977-1.138 2.5 2.5 0 0 1-.142-3.667l3-3Z\"\/><path d=\"M11.603 7.963a.75.75 0 0 0-.977 1.138 2.5 2.5 0 0 1 .142 3.667l-3 3a2.5 2.5 0 0 1-3.536-3.536l1.225-1.224a.75.75 0 0 0-1.061-1.06l-1.224 1.224a4 4 0 1 0 5.656 5.656l3-3a4 4 0 0 0-.225-5.865Z\"\/><\/svg><span class=\"copy-link__text\">Copy link to this calculation<\/span><\/button><span class=\"sr-only\" role=\"status\" id=\"copy-link-status\"><\/span><\/div><\/div><a href=\"#respond\" class=\"hidden transition-opacity duration-300 opacity-0 w-50 text-sm justify-center items-center gap-2 px-4 py-2 rounded bg-gray-200 text-gray-700 hover:bg-gray-300\" id=\"leave-comment\"><span class=\"icon icon-comments\" aria-hidden=\"true\"><\/span>Leave a Comment<\/a><\/form><\/section><section id=\"calc-reactions\" class=\"not-prose hidden my-12 bg-gradient-to-r from-primary-50 to-gray-50 border border-indigo-100 rounded-xl px-6 py-4 shadow-sm\" data-post=\"66776\" aria-live=\"polite\" aria-labelledby=\"calc-reactions-title\"><p id=\"calc-reactions-title\" class=\"text-sm text-gray-500 text-center mb-2\">How did this result make you feel?<\/p><div role=\"group\" aria-labelledby=\"calc-reactions-title\" class=\"grid grid-cols-3 sm:flex sm:flex-row sm:justify-around gap-4 sm:items-center sm:flex-wrap\"><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"like\"><span class=\"reaction-count\" data-reaction-count=\"like\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude00 <\/span><span class=\"reaction-description font-medium\">Like <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"helpful\"><span class=\"reaction-count\" data-reaction-count=\"helpful\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\udca1 <\/span><span class=\"reaction-description font-medium\">Helpful <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"confused\"><span class=\"reaction-count\" data-reaction-count=\"confused\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude15 <\/span><span class=\"reaction-description font-medium\">Confused <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"disappointed\"><span class=\"reaction-count\" data-reaction-count=\"disappointed\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\ud83d\ude1e <\/span><span class=\"reaction-description font-medium\">Disappointed <\/span><\/button><button type=\"button\" aria-pressed=\"false\" class=\"reaction-btn flex flex-col items-center gap-1 text-sm text-gray-700 hover:text-primary-600 cursor-pointer transition-transform hover:scale-105\" data-reaction=\"inaccurate\"><span class=\"reaction-count\" data-reaction-count=\"inaccurate\">0<\/span><span class=\"reaction text-3xl\" aria-hidden=\"true\">\u274c <\/span><span class=\"reaction-description font-medium\">Inaccurate <\/span><\/button><\/div><div id=\"reaction-message\" class=\"hidden mt-8 rounded-md border border-primary-100 bg-white\/50 backdrop-blur-sm px-4 py-2 text-sm text-center shadow-sm\"><\/div><\/section><div class=\"calcdash-ad not-prose calcdash-ad--calc_result calcdash-ad--in-article\"><ins class=\"adsbygoogle\" style=\"display:block\" data-ad-client=\"ca-pub-1721569815777345\" data-ad-slot=\"6317458308\" data-ad-layout=\"in-article\" data-ad-format=\"fluid\"><\/ins><script>(adsbygoogle = window.adsbygoogle || []).push({});<\/script><\/div>\n<style id=\"wpcoderpro-inline-1\">.formula-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section class=\"formula-box\" aria-labelledby=\"formula-title\">\r\n\t<div id=\"formula-title\" class=\"not-prose font-display mb-4\"><span class=\"icon icon-formula\" aria-hidden=\"true\"><\/span><h2>EC to TDS Formula<\/h2><\/div>\r\n\t<figure class=\"not-prose formula\">\r\n\t\t<figcaption class=\"formula-title\">Formula<\/figcaption>\r\n\t\t<div class=\"text-base text-gray-800\" id=\"formula\">\n\\[ \\text{TDS}\\,(\\text{ppm}) = \\text{EC}\\,(\\mu\\text{S\/cm}) \\times k \\\\\n\\text{where} \\quad 1\\ \\text{mS\/cm} = 1000\\ \\mu\\text{S\/cm}, \\quad 1\\ \\text{S\/m} = 10{,}000\\ \\mu\\text{S\/cm}\n\\]\n<\/div>\r\n\t<\/figure>\r\n\t<\/p>\n<p><strong>Where:<\/strong><\/p>\n<ul>\n<li>\\(\\text{TDS}\\) \u2014 total dissolved solids, in ppm (mg\/L for dilute water solutions)<\/li>\n<li>\\(\\text{EC}\\) \u2014 electrical conductivity of the water, expressed in \u00b5S\/cm<\/li>\n<li>\\(k\\) \u2014 the TDS conversion factor: 0.5 (NaCl scale), 0.64 (KCl scale) or 0.7 (natural water scale)<\/li>\n<\/ul>\n<p>The formula converts the conductivity reading into \u00b5S\/cm if needed, then multiplies it by the scale factor used by your meter. Because different salts conduct electricity differently, the factor is only an approximation of the true dissolved-solids content.<\/p>\n<p>\r\n<\/section>\n<style id=\"wpcoderpro-inline-459\">.calculation-box {\r\n\tborder-bottom: none !important;\r\n}<\/style><section id=\"calculation\" class=\"calculation-box\" aria-labelledby=\"calculation-title\">\r\n\t<div id=\"calculation-title\" class=\"not-prose font-display\"><span class=\"icon icon-unordered-list\" aria-hidden=\"true\"><\/span><h2>EC to TDS \u2013 Calculation Example<\/h2><\/div>\r\n\r\n<\/p>\n<p><strong>Example:<\/strong> a conductivity meter reads 500 \u00b5S\/cm in a hydroponic nutrient solution, and the meter uses the NaCl scale (factor 0.5).<\/p>\n<p>\\[ \\text{TDS} = 500\\ \\mu\\text{S\/cm} \\times 0.5 = 250\\ \\text{ppm} \\]<\/p>\n<p><strong>Result:<\/strong> the estimated TDS is 250 ppm (\u2248 250 mg\/L).<\/p>\n<p>\n\r\n<\/section>\n<h2>How to use the calculator<\/h2>\n<ol>\n<li>Enter your <strong>Electrical conductivity (EC)<\/strong> reading in the number field.<\/li>\n<li>Select the unit of the reading \u2014 <strong>\u00b5S\/cm<\/strong>, <strong>mS\/cm<\/strong> or <strong>S\/m<\/strong> \u2014 in the dropdown next to the value. Most hobby meters report \u00b5S\/cm; many laboratory instruments use mS\/cm.<\/li>\n<li>Choose the <strong>TDS conversion factor<\/strong> that matches your meter or application: <strong>0.5<\/strong> for the NaCl scale (common in the US and in hydroponics), <strong>0.64<\/strong> for the KCl scale, or <strong>0.7<\/strong> for the natural water scale (common in Europe). If you are unsure, check the meter's manual.<\/li>\n<li>Read the <strong>Total dissolved solids (TDS)<\/strong> result in ppm (mg\/L), together with a note showing the factor that was applied.<\/li>\n<\/ol>\n<h2>What are EC and TDS?<\/h2>\n<p>Electrical conductivity (EC) measures how well a water sample conducts electricity. Pure water is a very poor conductor, but dissolved ions \u2014 mainly calcium, magnesium, sodium, potassium, chloride, sulfate and bicarbonate \u2014 carry charge and raise the conductivity. The more dissolved ions there are, the higher the EC, so conductivity is a quick and reliable proxy for the total amount of dissolved material in water.<\/p>\n<p>Total dissolved solids (TDS) is the actual mass of dissolved substances per unit volume, usually expressed in mg\/L. In dilute aqueous solutions \u2014 drinking water, hydroponic solutions, aquariums \u2014 1 ppm is essentially equal to 1 mg\/L. Measuring TDS directly requires evaporating and weighing a sample, which is slow and impractical for routine checks. Instead, inexpensive meters measure EC and convert it to an estimated TDS using a fixed multiplication factor.<\/p>\n<p>The catch is that no single factor fits all waters. A chloride ion conducts more current than a bicarbonate ion of the same mass, so the TDS\/EC ratio depends on the ionic mix. Meter makers standardise on three common scales: 0.5 (sodium chloride solutions), 0.64 (potassium chloride solutions) and 0.7 (typical natural waters). Using the wrong factor can shift the reading by 40%, which is why comparing EC values directly is often safer than comparing TDS values from different meters.<\/p>\n<h2>Typical EC and TDS values<\/h2>\n<table>\n<thead>\n<tr>\n<th>Water type<\/th>\n<th>EC (\u00b5S\/cm)<\/th>\n<th>TDS at 0.5 (ppm)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Distilled \/ RO water<\/td>\n<td>0\u201350<\/td>\n<td>0\u201325<\/td>\n<\/tr>\n<tr>\n<td>Fresh drinking water<\/td>\n<td>50\u2013500<\/td>\n<td>25\u2013250<\/td>\n<\/tr>\n<tr>\n<td>Average tap water<\/td>\n<td>250\u2013750<\/td>\n<td>125\u2013375<\/td>\n<\/tr>\n<tr>\n<td>Hydroponic nutrient solution<\/td>\n<td>1000\u20132500<\/td>\n<td>500\u20131250<\/td>\n<\/tr>\n<tr>\n<td>Sea water<\/td>\n<td>\u2248 50,000<\/td>\n<td>\u2248 25,000<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Assumptions and limitations<\/h2>\n<ul>\n<li><strong>The result is an estimate.<\/strong> The true TDS\/EC ratio of your water may differ from the selected scale factor. For precise work, calibrate against a gravimetric or laboratory TDS measurement.<\/li>\n<li><strong>ppm \u2248 mg\/L holds only for dilute solutions.<\/strong> For brines and very concentrated liquids the density deviates from 1 kg\/L and the equivalence breaks down.<\/li>\n<li><strong>EC says nothing about which solids are present.<\/strong> Two waters with identical TDS can contain completely different minerals \u2014 harmful contaminants like heavy metals can raise EC just like benign salts. If you also work with concentration units, the <a href=\"https:\/\/wpcalc.com\/en\/converters\/ppm-to-percent-mg-l-converter\/\">PPM Converter<\/a> helps translate the result.<\/li>\n<li><strong>Always match the meter's factor.<\/strong> If your TDS meter uses the 0.7 scale and you convert an EC reading with 0.5, the two numbers will disagree even for the same water.<\/li>\n<li><strong>Temperature matters.<\/strong> EC rises by roughly 2% per \u00b0C. Good meters apply automatic temperature compensation (ATC); check whether yours does before comparing readings taken at different temperatures.<\/li>\n<\/ul>\n<h2>Practical tips<\/h2>\n<p>Hydroponic and aquarium growers usually track EC rather than TDS precisely because it avoids the factor ambiguity \u2014 an EC of 1.4 mS\/cm means the same thing everywhere. If you follow feeding charts, note whether they quote EC or TDS and at which scale before converting. For brewing and gardening applications that involve sugar solutions rather than salts, a refractometer-based tool such as the <a href=\"https:\/\/wpcalc.com\/en\/converters\/brix-to-specific-gravity-converter\/\">Brix to Specific Gravity Calculator<\/a> is the more appropriate instrument, since sugars barely affect conductivity.<\/p>\n<p>When monitoring water quality over time, keep the meter, the factor and the temperature conditions consistent so the trend is meaningful. A slowly rising TDS in a boiler, cooling loop or irrigation line is often the first warning of scale formation or contamination long before visible deposits appear.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Convert an electrical conductivity (EC) reading in \u00b5S\/cm, mS\/cm or S\/m into an estimated TDS value in ppm. Choose the conversion factor your meter uses (0.5, 0.64 or 0.7) and get an instant result.<\/p>\n","protected":false},"author":3168,"featured_media":0,"comment_status":"open","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[3],"tags":[17],"class_list":["post-66776","post","type-post","status-publish","format-standard","hentry","category-converters","tag-chemistry-units"],"acf":[],"_links":{"self":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/66776","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/users\/3168"}],"replies":[{"embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/comments?post=66776"}],"version-history":[{"count":1,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/66776\/revisions"}],"predecessor-version":[{"id":66777,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/posts\/66776\/revisions\/66777"}],"wp:attachment":[{"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/media?parent=66776"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/categories?post=66776"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wpcalc.com\/en\/wp-json\/wp\/v2\/tags?post=66776"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}