#supo-tinh-tien-dien{–navy:#1a4d8f;–blue:#2f7fd6;–green:#4caf3f;–orange:#f7941d;–line:#dfe6ef;–soft:#f5f8fc;font-family:inherit;color:#1f2a37;max-width:860px;margin:0 auto;line-height:1.55;box-sizing:border-box} #supo-tinh-tien-dien *{box-sizing:border-box} #supo-tinh-tien-dien .stc-card{background:#fff;border:1px solid var(–line);border-radius:14px;margin:0 0 24px;overflow:hidden;box-shadow:0 2px 10px rgba(26,77,143,.06)} #supo-tinh-tien-dien .stc-head{background:linear-gradient(90deg,var(–navy),var(–blue));color:#fff;padding:14px 18px;font-size:19px;font-weight:700;margin:0} #supo-tinh-tien-dien .stc-body{padding:18px} #supo-tinh-tien-dien .stc-label{display:block;font-weight:700;font-size:18px;color:var(–navy);margin:0 0 10px} #supo-tinh-tien-dien .stc-inputwrap{display:flex;align-items:center;width:100%;max-width:520px;border:3px solid var(–orange);border-radius:14px;background:#fff6ec;overflow:hidden;box-shadow:0 0 0 5px rgba(247,148,29,.15);transition:box-shadow .2s} #supo-tinh-tien-dien .stc-inputwrap:focus-within{box-shadow:0 0 0 7px rgba(247,148,29,.3)} #supo-tinh-tien-dien .stc-input{flex:1;min-width:0;border:0;background:transparent;padding:16px 18px;font-size:34px;font-weight:800;color:#1f2a37;outline:none;line-height:1.2;height:auto;box-shadow:none;margin:0} #supo-tinh-tien-dien .stc-unit{padding:0 18px;font-size:20px;font-weight:700;color:#fff;background:var(–orange);align-self:stretch;display:flex;align-items:center} #supo-tinh-tien-dien .stc-hint{font-size:14px;color:#6b7785;margin:8px 0 0} #supo-tinh-tien-dien .stc-stats{display:flex;flex-wrap:wrap;gap:12px;margin:18px 0} #supo-tinh-tien-dien .stc-stat{flex:1 1 200px;background:var(–soft);border-left:4px solid var(–green);border-radius:8px;padding:10px 14px} #supo-tinh-tien-dien .stc-stat span{display:block;font-size:13px;color:#5b6775} #supo-tinh-tien-dien .stc-stat b{font-size:22px;color:var(–navy)} #supo-tinh-tien-dien .stc-tablewrap{overflow-x:auto;-webkit-overflow-scrolling:touch} #supo-tinh-tien-dien table{width:100%;border-collapse:collapse;font-size:13px;margin:0} #supo-tinh-tien-dien th{background:#eef3fa;color:var(–navy);text-align:left;padding:8px 6px;border-bottom:2px solid var(–line);font-size:12px;line-height:1.3;width:1%} #supo-tinh-tien-dien td{padding:8px 6px;border-bottom:1px solid var(–line);white-space:nowrap;color:#5b6775;width:1%} #supo-tinh-tien-dien td.num,#supo-tinh-tien-dien th.num{text-align:right} #supo-tinh-tien-dien th.money{width:auto;background:var(–navy);color:#fff;font-size:14px;text-align:right;padding-right:14px} #supo-tinh-tien-dien td.money{width:auto;font-size:18px;font-weight:800;color:var(–navy);background:#f5f8fc;text-align:right;padding-right:14px} #supo-tinh-tien-dien tr.stc-off td{color:#a9b3bf} #supo-tinh-tien-dien tr.stc-total td{font-weight:700;background:#fff6ec;color:#1f2a37;border-top:2px solid var(–orange);font-size:14px} #supo-tinh-tien-dien tr.stc-total td.money{font-size:22px;color:#fff;background:var(–orange)} #supo-tinh-tien-dien tr.stc-off td.money{color:#a9b3bf;font-weight:600;font-size:15px} #supo-tinh-tien-dien .stc-bar{display:inline-block;height:8px;border-radius:4px;background:var(–orange);vertical-align:middle;margin-right:6px} #supo-tinh-tien-dien .stc-insight{margin:16px 0 0;padding:12px 14px;border-radius:10px;background:#eef8ec;border:1px solid #cfe8c9;color:#24502a;font-size:15px} #supo-tinh-tien-dien .stc-note{font-size:13px;color:#6b7785;margin:0 0 24px} #supo-tinh-tien-dien .stc-cta{background:linear-gradient(90deg,var(–navy),var(–blue));color:#fff;border-radius:14px;padding:18px;text-align:center} #supo-tinh-tien-dien .stc-cta p{margin:0 0 12px;font-size:16px} #supo-tinh-tien-dien .stc-btn{display:inline-block;background:var(–orange);color:#fff !important;text-decoration:none;font-weight:700;padding:11px 20px;border-radius:30px;margin:4px} #supo-tinh-tien-dien .stc-btn.alt{background:#fff;color:var(–navy) !important} @media (max-width:600px){#supo-tinh-tien-dien .stc-head{font-size:17px}#supo-tinh-tien-dien .stc-body{padding:14px}#supo-tinh-tien-dien .stc-input{font-size:28px;padding:14px}#supo-tinh-tien-dien .stc-unit{font-size:16px;padding:0 12px}#supo-tinh-tien-dien th{font-size:11px;padding:7px 4px}#supo-tinh-tien-dien td{font-size:12px;padding:7px 4px}#supo-tinh-tien-dien td.money{font-size:15px;padding-right:8px}#supo-tinh-tien-dien tr.stc-total td.money{font-size:17px}}

📌 Kết quả mang tính ước tính tham khảo, tính theo biểu giá điện sinh hoạt bậc thang hiện hành của EVN (6 bậc, thuế VAT 8%), số ngày trong tháng tính là 30. Hoá đơn thực tế có thể chênh lệch nhẹ do kỳ ghi chỉ số, số ngày trong kỳ và cách làm tròn của điện lực.

(function(){ var VAT=0.08,DAYS=30; var TIERS=[{name:’Bậc 1′,range:’0 – 50 kWh’,price:1984,cap:50},{name:’Bậc 2′,range:’51 – 100 kWh’,price:2050,cap:50},{name:’Bậc 3′,range:’101 – 200 kWh’,price:2380,cap:100},{name:’Bậc 4′,range:’201 – 300 kWh’,price:2998,cap:100},{name:’Bậc 5′,range:’301 – 400 kWh’,price:3350,cap:100},{name:’Bậc 6′,range:’Từ 401 kWh’,price:3460,cap:Infinity}]; var $=function(id){return document.getElementById(id);}; function parseNum(s){var d=String(s).replace(/[^0-9]/g,”);return d?parseInt(d,10):0;} function fmt(n,dec){dec=dec||0;return Number(n).toLocaleString(‘vi-VN’,{minimumFractionDigits:dec,maximumFractionDigits:dec});} function priceVAT(t){return t.price*(1+VAT);} function calcForward(kwh){var left=kwh,total=0,rows=[];for(var i=0;i<TIERS.length;i++){var t=TIERS[i],q=Math.min(left,t.cap),m=q*priceVAT(t);left-=q;total+=m;rows.push({t:t,q:q,m:m});}return{rows:rows,total:total};} function calcReverse(bill){var left=bill,kwh=0,rows=[];for(var i=0;i<TIERS.length;i++){var t=TIERS[i],pv=priceVAT(t),m=Math.min(left,t.cap*pv),q=m/pv;left-=m;kwh+=q;rows.push({t:t,q:q,m:m});}return{rows:rows,kwh:kwh};} function renderForward(){var kwh=parseNum($('stc-kwh').value),r=calcForward(kwh),h=''; r.rows.forEach(function(x){h+='0?”:’ class=”stc-off”‘)+’>‘+x.t.name.replace(‘Bậc ‘,’B’)+’‘+fmt(x.t.price)+’‘+fmt(priceVAT(x.t))+’‘+fmt(x.q)+’‘+fmt(x.m)+’‘;}); h+=’TỔNG CỘNG‘+fmt(kwh)+’‘+fmt(r.total)+’‘; $(‘stc-f-rows’).innerHTML=h;$(‘stc-f-total’).textContent=fmt(r.total)+’ đ’;$(‘stc-f-avg’).textContent=(kwh>0?fmt(r.total/kwh):0)+’ đ’;} function renderReverse(){var bill=parseNum($(‘stc-bill’).value),r=calcReverse(bill),h=”,top=null; r.rows.forEach(function(x){var pct=bill>0?x.m/bill*100:0;if(x.q>0)top={x:x,pct:pct};h+=’0?”:’ class=”stc-off”‘)+’>‘+x.t.name.replace(‘Bậc ‘,’B’)+’‘+fmt(priceVAT(x.t))+’‘+fmt(x.q,1)+’‘+fmt(x.m)+’‘+fmt(pct)+’%‘;}); h+=’Tổng‘+fmt(r.kwh,1)+’‘+fmt(bill)+’100%‘; $(‘stc-r-rows’).innerHTML=h;$(‘stc-r-kwh’).textContent=fmt(r.kwh,1)+’ kWh’;$(‘stc-r-day’).textContent=fmt(r.kwh/DAYS,1)+’ kWh/ngày’; var ins=$(‘stc-r-insight’);if(top&&bill>0){ins.style.display=’block’;ins.innerHTML=’💡 Phần điện ở ‘+top.x.t.name+’ (giá cao nhất anh em đang chịu, ‘+fmt(priceVAT(top.x.t))+’ đ/kWh) chiếm ‘+fmt(top.pct)+’% hoá đơn. Điện mặt trời tự dùng sẽ cắt vào phần điện bậc cao này trước, nên hoá đơn càng nằm nhiều ở bậc cao thì hiệu quả tiết kiệm càng rõ.’;}else{ins.style.display=’none’;}} function bind(id,fn){var el=$(id);el.addEventListener(‘input’,function(){var n=parseNum(el.value);el.value=n?fmt(n):”;fn();});fn();} bind(‘stc-kwh’,renderForward);bind(‘stc-bill’,renderReverse); })();