{"id":1456,"date":"2026-09-21T14:39:48","date_gmt":"2026-09-21T06:39:48","guid":{"rendered":"https:\/\/www.paiyipower.com\/voltage-drop-calculator\/"},"modified":"2026-09-21T14:42:52","modified_gmt":"2026-09-21T06:42:52","slug":"voltage-drop-calculator","status":"publish","type":"page","link":"https:\/\/www.paiyipower.com\/pt\/voltage-drop-calculator\/","title":{"rendered":"Voltage Drop and Wire Gauge Calculator"},"content":{"rendered":"<p><strong>Free tool, no sign-up.<\/strong> Enter the voltage, current, conductor gauge and run length, and see how much voltage actually reaches the device \u2014 plus the maximum run length for a 5% drop and the minimum gauge for the target you set. It works for 12V and 24V CCTV runs, gate operators, access control and LED feeds, in AWG or mm\u00b2.<\/p>\n<div id=\"pxd-vd\">\n<style>\n#pxd-vd{font-family:-apple-system,\"Segoe UI\",Roboto,\"Helvetica Neue\",Arial,sans-serif;color:#17202a;max-width:940px;margin:0 auto;line-height:1.6;}\n#pxd-vd *{box-sizing:border-box;}\n#pxd-vd h2{font-size:24px;margin:0 0 6px;border:none;padding:0;}\n#pxd-vd .lead{color:#59636e;font-size:15px;margin:0 0 20px;}\n#pxd-vd .grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px;}\n#pxd-vd .card{background:#fff;border:1px solid #d9dee3;border-radius:8px;padding:16px 18px;}\n#pxd-vd h3{font-size:15px;margin:0 0 12px;color:#2f6b4f;}\n#pxd-vd label{display:block;font-size:13px;color:#59636e;margin:0 0 4px;}\n#pxd-vd input,#pxd-vd select{width:100%;padding:9px 10px;border:1px solid #d9dee3;border-radius:5px;font-size:15px;font-family:inherit;color:#17202a;background:#fff;}\n#pxd-vd input:focus,#pxd-vd select:focus{outline:2px solid #1264a3;outline-offset:-1px;}\n#pxd-vd .f{margin-bottom:12px;}\n#pxd-vd .hint{font-size:12px;color:#59636e;margin-top:3px;}\n#pxd-vd .out{margin-top:22px;background:#17202a;color:#fff;border-radius:8px;padding:20px 22px;}\n#pxd-vd .big{display:flex;flex-wrap:wrap;gap:26px;}\n#pxd-vd .big>div{flex:1 1 150px;}\n#pxd-vd .big .lbl{font-size:12px;color:#a9b4bd;text-transform:uppercase;letter-spacing:.5px;}\n#pxd-vd .big .val{font-size:28px;font-weight:700;}\n#pxd-vd #pxd-vd-verdict{margin-top:16px;font-size:15px;font-weight:600;padding:10px 14px;border-radius:6px;color:#fff;}\n#pxd-vd .v-ok{background:#2f6b4f;}\n#pxd-vd .v-mid{background:#b8860b;}\n#pxd-vd .v-bad{background:#c0392b;}\n#pxd-vd table{width:100%;border-collapse:collapse;margin-top:20px;font-size:14px;background:#fff;}\n#pxd-vd th,#pxd-vd td{border:1px solid #d9dee3;padding:9px 11px;text-align:left;}\n#pxd-vd th{background:#f5f7f8;font-weight:600;}\n#pxd-vd td.n{text-align:right;font-variant-numeric:tabular-nums;}\n#pxd-vd .two{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:14px;margin-top:20px;}\n#pxd-vd .box{background:#fff;border:1px solid #d9dee3;border-left:4px solid #1264a3;border-radius:6px;padding:14px 16px;}\n#pxd-vd .box .k{font-size:12px;color:#59636e;text-transform:uppercase;letter-spacing:.4px;}\n#pxd-vd .box .v{font-size:22px;font-weight:700;color:#1264a3;}\n#pxd-vd .box .s{font-size:13px;color:#59636e;margin-top:4px;}\n#pxd-vd .note{font-size:13px;color:#59636e;background:#fff;border-left:4px solid #1264a3;border-radius:5px;padding:12px 16px;margin-top:18px;}\n#pxd-vd .lang{text-align:right;margin-bottom:10px;}\n#pxd-vd .lang button{font-size:12px;padding:4px 10px;border:1px solid #d9dee3;background:#fff;border-radius:4px;cursor:pointer;color:#59636e;}\n#pxd-vd .lang button.on{background:#1264a3;color:#fff;border-color:#1264a3;}\n<\/style>\n<div class=\"lang\"><button id=\"pxd-vd-pt\" onclick=\"PXD.setLang('pt')\">PT<\/button> <button id=\"pxd-vd-en\" onclick=\"PXD.setLang('en')\">EN<\/button><\/div>\n<h2 id=\"pxd-vd-title\"><\/h2>\n<p class=\"lead\" id=\"pxd-vd-lead\">\n<div class=\"grid\">\n<div class=\"card\">\n<h3 id=\"pxd-vd-h-load\"><\/h3>\n<div class=\"f\"><label id=\"pxd-vd-l-v\"><\/label><input type=\"number\" id=\"pxd-vd-v\" value=\"12\" min=\"0.1\" step=\"0.1\"><\/div>\n<div class=\"f\"><label id=\"pxd-vd-l-i\"><\/label><input type=\"number\" id=\"pxd-vd-i\" value=\"2\" min=\"0.01\" step=\"0.1\"><\/div>\n<div class=\"f\"><label id=\"pxd-vd-l-len\"><\/label><input type=\"number\" id=\"pxd-vd-len\" value=\"20\" min=\"0.1\" step=\"1\"><\/p>\n<div class=\"hint\" id=\"pxd-vd-h-len\"><\/div>\n<\/div><\/div>\n<div class=\"card\">\n<h3 id=\"pxd-vd-h-cable\"><\/h3>\n<div class=\"f\"><label id=\"pxd-vd-l-g\"><\/label><select id=\"pxd-vd-g\" onchange=\"PXD.calc()\"><\/select><\/div>\n<div class=\"f\"><label id=\"pxd-vd-l-mat\"><\/label><select id=\"pxd-vd-mat\" onchange=\"PXD.calc()\"><option value=\"cu\">\u2014<\/option><option value=\"al\">\u2014<\/option><\/select><\/div>\n<div class=\"f\"><label id=\"pxd-vd-l-t\"><\/label><input type=\"number\" id=\"pxd-vd-t\" value=\"20\" min=\"-10\" max=\"120\" step=\"5\"><\/p>\n<div class=\"hint\" id=\"pxd-vd-h-t\"><\/div>\n<\/div>\n<div class=\"f\"><label id=\"pxd-vd-l-target\"><\/label><input type=\"number\" id=\"pxd-vd-target\" value=\"5\" min=\"0.5\" max=\"30\" step=\"0.5\"><\/div>\n<\/p><\/div>\n<\/div>\n<div class=\"out\">\n<div class=\"big\">\n<div>\n<div class=\"lbl\" id=\"pxd-vd-o1l\"><\/div>\n<div class=\"val\" id=\"pxd-vd-o1\">\u2014<\/div>\n<\/div>\n<div>\n<div class=\"lbl\" id=\"pxd-vd-o2l\"><\/div>\n<div class=\"val\" id=\"pxd-vd-o2\">\u2014<\/div>\n<\/div>\n<div>\n<div class=\"lbl\" id=\"pxd-vd-o3l\"><\/div>\n<div class=\"val\" id=\"pxd-vd-o3\">\u2014<\/div>\n<\/div><\/div>\n<div id=\"pxd-vd-verdict\"><\/div>\n<\/div>\n<div class=\"two\">\n<div class=\"box\">\n<div class=\"k\" id=\"pxd-vd-b1k\"><\/div>\n<div class=\"v\" id=\"pxd-vd-b1v\">\u2014<\/div>\n<div class=\"s\" id=\"pxd-vd-b1s\"><\/div>\n<\/div>\n<div class=\"box\">\n<div class=\"k\" id=\"pxd-vd-b2k\"><\/div>\n<div class=\"v\" id=\"pxd-vd-b2v\">\u2014<\/div>\n<div class=\"s\" id=\"pxd-vd-b2s\"><\/div>\n<\/div>\n<\/div>\n<table>\n<thead>\n<tr>\n<th id=\"pxd-vd-th1\"><\/th>\n<th id=\"pxd-vd-th2\" style=\"text-align:right;\"><\/th>\n<\/tr>\n<\/thead>\n<tbody id=\"pxd-vd-body\"><\/tbody>\n<\/table>\n<div class=\"note\" id=\"pxd-vd-note\"><\/div>\n<p><script>\n(function(){\n  var GAUGES = [\n    {g:'24 AWG', a:0.205},{g:'22 AWG', a:0.326},{g:'20 AWG', a:0.518},{g:'18 AWG', a:0.823},\n    {g:'16 AWG', a:1.31},{g:'14 AWG', a:2.08},{g:'12 AWG', a:3.31},{g:'10 AWG', a:5.26},\n    {g:'8 AWG', a:8.37},{g:'6 AWG', a:13.3},{g:'4 AWG', a:21.2},{g:'2 AWG', a:33.6},\n    {g:'0.5 mm\u00b2', a:0.5},{g:'0.75 mm\u00b2', a:0.75},{g:'1.0 mm\u00b2', a:1.0},{g:'1.5 mm\u00b2', a:1.5},\n    {g:'2.5 mm\u00b2', a:2.5},{g:'4 mm\u00b2', a:4.0},{g:'6 mm\u00b2', a:6.0},{g:'10 mm\u00b2', a:10.0},{g:'16 mm\u00b2', a:16.0}\n  ];<\/p>\n<p>  var T = {\n    pt: {\n      title:\"Calculadora de Queda de Tens\u00e3o e Bitola\",\n      lead:\"Descubra quanta tens\u00e3o a c\u00e2mera, o motor do port\u00e3o ou o ponto de LED realmente recebe \u2014 e qual bitola voc\u00ea precisa para ficar dentro de 5%.\",\n      hLoad:\"Carga e dist\u00e2ncia\", hCable:\"Cabo e condi\u00e7\u00f5es\",\n      lv:\"Tens\u00e3o de sa\u00edda (V)\", li:\"Corrente (A)\",\n      llen:\"Comprimento do trecho, um sentido (m)\",\n      hlen:\"Informe a dist\u00e2ncia f\u00edsica. A calculadora j\u00e1 considera o caminho de ida e volta.\",\n      lg:\"Bitola do condutor\", lmat:\"Material do condutor\", lt:\"Temperatura do condutor (\u00b0C)\",\n      ht:\"A resist\u00eancia do cobre sobe com a temperatura. Em pain\u00e9is e eletrodutos fechados, 40\u201360 \u00b0C \u00e9 realista.\",\n      ltarget:\"Queda m\u00e1xima aceit\u00e1vel (%)\",\n      o1l:\"Queda de tens\u00e3o\", o2l:\"Queda percentual\", o3l:\"Tens\u00e3o na carga\",\n      ok:\"Dentro do recomendado (abaixo de 3%).\",\n      ok2:\"Aceit\u00e1vel (3% a 5%). \u00c9 o limite usual de projeto.\",\n      bad:\"Acima de 5%: acima do recomendado. Aumente a bitola, reduza o trecho ou mude para 24V.\",\n      bad2:\"Acima de 10%: a tens\u00e3o que chega \u00e9 insuficiente. A arquitetura est\u00e1 errada para esta tens\u00e3o.\",\n      b1k:\"Comprimento m\u00e1ximo para 5%\",\n      b1s:\"Com esta bitola, nesta corrente, a partir daqui a queda passa de 5%.\",\n      b2k:\"Bitola m\u00ednima para o seu alvo\",\n      b2s:\"Menor bitola da lista que atende \u00e0 queda m\u00e1xima que voc\u00ea definiu.\",\n      b2none:\"Nenhuma bitola da lista atende. Reduza o trecho, a corrente, ou aumente a tens\u00e3o.\",\n      th1:\"Resultado\", th2:\"Valor\",\n      r1:\"Resist\u00eancia do condutor (ida e volta)\", r2:\"Resist\u00eancia por metro (a esta temperatura)\",\n      r3:\"Queda de tens\u00e3o\", r4:\"Queda percentual\", r5:\"Tens\u00e3o efetiva na carga\",\n      r6:\"\u00c1rea do condutor selecionado\", r7:\"Percentual que a carga efetivamente recebe\",\n      matCu:\"Cobre\", matAl:\"Alum\u00ednio\",\n      note:\"O c\u00e1lculo usa a resistividade do cobre e do alum\u00ednio corrigida pela temperatura. Ele estima a queda em regime; picos de partida de motor produzem quedas momentaneamente maiores. Confira a ficha do cabo para os valores exatos do fabricante. Veja o contexto em <a href='\/pt\/cctv-power-supply-brazil\/'>fonte para CFTV no Brasil<\/a>.\"\n    },\n    en: {\n      title:\"Voltage Drop and Wire Gauge Calculator\",\n      lead:\"Find out what voltage the camera, gate motor or LED run actually receives \u2014 and which gauge keeps you inside 5%.\",\n      hLoad:\"Load and distance\", hCable:\"Cable and conditions\",\n      lv:\"Output voltage (V)\", li:\"Current (A)\",\n      llen:\"Run length, one way (m)\",\n      hlen:\"Enter the physical distance. The calculator already accounts for the return path.\",\n      lg:\"Conductor gauge\", lmat:\"Conductor material\", lt:\"Conductor temperature (\u00b0C)\",\n      ht:\"Copper resistance rises with temperature. Inside panels and closed conduit, 40\u201360 \u00b0C is realistic.\",\n      ltarget:\"Maximum acceptable drop (%)\",\n      o1l:\"Voltage drop\", o2l:\"Drop percentage\", o3l:\"Voltage at the load\",\n      ok:\"Inside the recommended range (below 3%).\",\n      ok2:\"Acceptable (3% to 5%). This is the usual design limit.\",\n      bad:\"Above 5%: over the limit. Increase the gauge, shorten the run, or move to 24V.\",\n      bad2:\"Above 10%: the voltage arriving is insufficient. The architecture is wrong for this voltage.\",\n      b1k:\"Maximum length for 5%\",\n      b1s:\"At this gauge and current, drop passes 5% beyond this distance.\",\n      b2k:\"Minimum gauge for your target\",\n      b2s:\"Smallest gauge in the list that meets the drop limit you set.\",\n      b2none:\"No gauge in the list meets it. Shorten the run, reduce the current, or raise the voltage.\",\n      th1:\"Result\", th2:\"Value\",\n      r1:\"Conductor resistance (there and back)\", r2:\"Resistance per metre (at this temperature)\",\n      r3:\"Voltage drop\", r4:\"Drop percentage\", r5:\"Effective voltage at the load\",\n      r6:\"Selected conductor area\", r7:\"Percentage the load actually receives\",\n      matCu:\"Copper\", matAl:\"Aluminium\",\n      note:\"The calculation uses temperature-corrected resistivity for copper and aluminium. It estimates steady-state drop; motor start-up peaks produce larger momentary drops. Check the cable datasheet for the manufacturer's exact figures. Context: <a href='\/cctv-camera-power-supply-oem\/'>CCTV camera power supply<\/a>.\"\n    }\n  };<\/p>\n<p>  var LANG = (document.documentElement.lang || 'en').toLowerCase().indexOf('pt') === 0 ? 'pt' : 'en';\n  var $ = function(id){ return document.getElementById(id); };<\/p>\n<p>  function fmt(v, dec){\n    if(!isFinite(v)) v = 0;\n    var loc = LANG === 'pt' ? 'pt-BR' : 'en-US';\n    return new Intl.NumberFormat(loc, {minimumFractionDigits: dec, maximumFractionDigits: dec}).format(v);\n  }<\/p>\n<p>  function buildGauges(){\n    var s = $('pxd-vd-g'), html = '';\n    for(var i = 0; i < GAUGES.length; i++){\n      html += '<option value=\"' + GAUGES[i].a + '\"' + (GAUGES[i].g === '18 AWG' ? ' selected' : '') + '>' + GAUGES[i].g + '<\/option>';\n    }\n    s.innerHTML = html;\n  }<\/p>\n<p>  function gaugeLabel(a){\n    for(var i = 0; i < GAUGES.length; i++){ if(Math.abs(GAUGES[i].a - a) < 1e-9) return GAUGES[i].g; }\n    return fmt(a, 3) + ' mm\u00b2';\n  }\n\n  function setLang(l){\n    LANG = l;\n    var t = T[l];\n    $('pxd-vd-pt').className = (l === 'pt') ? 'on' : '';\n    $('pxd-vd-en').className = (l === 'en') ? 'on' : '';\n    $('pxd-vd-title').textContent = t.title;\n    $('pxd-vd-lead').textContent = t.lead;\n    $('pxd-vd-h-load').textContent = t.hLoad; $('pxd-vd-h-cable').textContent = t.hCable;\n    $('pxd-vd-l-v').textContent = t.lv; $('pxd-vd-l-i').textContent = t.li;\n    $('pxd-vd-l-len').textContent = t.llen; $('pxd-vd-h-len').textContent = t.hlen;\n    $('pxd-vd-l-g').textContent = t.lg; $('pxd-vd-l-mat').textContent = t.lmat;\n    $('pxd-vd-l-t').textContent = t.lt; $('pxd-vd-h-t').textContent = t.ht;\n    $('pxd-vd-l-target').textContent = t.ltarget;\n    $('pxd-vd-o1l').textContent = t.o1l; $('pxd-vd-o2l').textContent = t.o2l; $('pxd-vd-o3l').textContent = t.o3l;\n    $('pxd-vd-b1k').textContent = t.b1k; $('pxd-vd-b1s').textContent = t.b1s;\n    $('pxd-vd-b2k').textContent = t.b2k; $('pxd-vd-b2s').textContent = t.b2s;\n    $('pxd-vd-th1').textContent = t.th1; $('pxd-vd-th2').textContent = t.th2;\n    var mat = $('pxd-vd-mat');\n    mat.options[0].text = t.matCu; mat.options[1].text = t.matAl;\n    $('pxd-vd-note').innerHTML = t.note;\n    calc();\n  }\n\n  function num(id){ return parseFloat($(id).value) || 0; }\n\n  function calc(){\n    var t = T[LANG];\n    var V = num('pxd-vd-v'), I = num('pxd-vd-i'), L = num('pxd-vd-len');\n    var area = parseFloat($('pxd-vd-g').value) || 0.823;\n    var mat = $('pxd-vd-mat').value;\n    var Tdeg = num('pxd-vd-t');\n    var target = num('pxd-vd-target') || 5;\n\n    var rho20 = (mat === 'cu') ? 0.017241 : 0.028264;\n    var alpha = (mat === 'cu') ? 0.00393 : 0.00403;\n    var rho = rho20 * (1 + alpha * (Tdeg - 20));\n\n    var RperM = rho \/ area;\n    var R = rho * (2 * L) \/ area;\n    var drop = I * R;\n    var pct = V > 0 ? (drop \/ V) * 100 : 0;\n    var vl = V - drop;\n    var recv = V > 0 ? (vl \/ V) * 100 : 0;<\/p>\n<p>    $('pxd-vd-o1').textContent = fmt(drop, 2) + ' V';\n    $('pxd-vd-o2').textContent = fmt(pct, 2) + '%';\n    $('pxd-vd-o3').textContent = fmt(vl, 2) + ' V';<\/p>\n<p>    var vEl = $('pxd-vd-verdict'), msg, cls;\n    if(pct < 3){ msg = t.ok; cls = 'v-ok'; }\n    else if(pct <= 5){ msg = t.ok2; cls = 'v-mid'; }\n    else if(pct <= 10){ msg = t.bad; cls = 'v-bad'; }\n    else { msg = t.bad2; cls = 'v-bad'; }\n    vEl.className = cls; vEl.textContent = msg;\n\n    var lmax = (I > 0) ? ((V * 0.05 \/ I) * area \/ (rho * 2)) : 0;\n    $('pxd-vd-b1v').textContent = fmt(lmax, 1) + ' m';<\/p>\n<p>    var needA = (V > 0 && I > 0 && L > 0) ? (rho * 2 * L * I) \/ (V * target \/ 100) : 0;\n    var pick = null;\n    for(var i = 0; i < GAUGES.length; i++){\n      if(GAUGES[i].a >= needA && (pick === null || GAUGES[i].a < pick.a)){ pick = GAUGES[i]; }\n    }\n    if(needA <= 0){ $('pxd-vd-b2v').textContent = '\u2014'; }\n    else if(pick){ $('pxd-vd-b2v').textContent = pick.g; }\n    else { $('pxd-vd-b2v').textContent = '\u2014'; $('pxd-vd-b2s').textContent = t.b2none; }\n\n    var rows = [\n      [t.r1, fmt(R, 4) + ' \u03a9'],\n      [t.r2, fmt(RperM, 5) + ' \u03a9\/m'],\n      [t.r3, fmt(drop, 3) + ' V'],\n      [t.r4, fmt(pct, 2) + '%'],\n      [t.r5, fmt(vl, 3) + ' V'],\n      [t.r6, fmt(area, 3) + ' mm\u00b2'],\n      [t.r7, fmt(recv, 2) + '%']\n    ];\n    var html = '';\n    for(var j = 0; j < rows.length; j++){\n      html += '\n\n<tr>\n<td>' + rows[j][0] + '<\/td>\n<td class=\"n\">' + rows[j][1] + '<\/td>\n<\/tr>\n<p>';\n    }\n    $('pxd-vd-body').innerHTML = html;\n  }<\/p>\n<p>  window.PXD = { setLang: setLang, calc: calc };\n  buildGauges();\n  setLang(LANG);\n})();\n<\/script>\n<\/div>\n<p><em>Related reading: <a href='https:\/\/www.paiyipower.com\/cctv-camera-power-supply-oem\/'>CCTV camera power supply OEM<\/a>, <a href='https:\/\/www.paiyipower.com\/cctv-power-supply-brazil\/'>CCTV power supply Brazil<\/a>, <a href='https:\/\/www.paiyipower.com\/electric-gate-power-supply-brazil\/'>electric gate power supply Brazil<\/a>, <a href='https:\/\/www.paiyipower.com\/led-power-supply-oem\/'>LED power supply OEM<\/a>.<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Free tool, no sign-up. Enter the voltage, current, conductor gauge and run length, and see how much voltage actually reaches the device \u2014 plus the maximum run length for a 5% drop and the minimum gauge for the target you set. It works for 12V and 24V CCTV runs, gate operators, access control and LED [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-1456","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.paiyipower.com\/pt\/wp-json\/wp\/v2\/pages\/1456","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.paiyipower.com\/pt\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.paiyipower.com\/pt\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.paiyipower.com\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.paiyipower.com\/pt\/wp-json\/wp\/v2\/comments?post=1456"}],"version-history":[{"count":2,"href":"https:\/\/www.paiyipower.com\/pt\/wp-json\/wp\/v2\/pages\/1456\/revisions"}],"predecessor-version":[{"id":1462,"href":"https:\/\/www.paiyipower.com\/pt\/wp-json\/wp\/v2\/pages\/1456\/revisions\/1462"}],"wp:attachment":[{"href":"https:\/\/www.paiyipower.com\/pt\/wp-json\/wp\/v2\/media?parent=1456"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}