toolbox/compound-interest.html at main · 100millionusd/toolbox · GitHub

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<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Free Compound Interest Calculator — Investment Growth</title>
  <meta name="description" content="Calculate compound interest on investments and savings. See growth over time with monthly contributions. Compare interest rates. Free online compound interest calculator.">
  <link rel="canonical" href="https://www.quicktools.mom/compound-interest.html">
  <meta property="og:title" content="">
  <meta property="og:description" content="">
  <meta property="og:type" content="website">
  <meta property="og:url" content="https://www.quicktools.mom/compound-interest.html">
  <meta name="twitter:card" content="summary">
  <link rel="stylesheet" href="style.css">
  <script async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js?client=ca-pub-2658921743607446" crossorigin="anonymous"></script>
<script type="application/ld+json">{"@context":"https://schema.org","@type":"FAQPage","mainEntity":[{"@type":"Question","name":"Is Compound Interest Calculator free to use?","acceptedAnswer":{"@type":"Answer","text":"Yes! Compound Interest Calculator is completely free with no signup required. It runs entirely in your browser — your data never leaves your device."}},{"@type":"Question","name":"How do I use Compound Interest Calculator?","acceptedAnswer":{"@type":"Answer","text":"Simply enter your values in the input fields above and the results update instantly. No button clicks needed — everything calculates in real-time."}},{"@type":"Question","name":"Is my data safe with Compound Interest Calculator?","acceptedAnswer":{"@type":"Answer","text":"Absolutely. Compound Interest Calculator runs 100% client-side in your browser using JavaScript. No data is uploaded, stored, or shared with any server. Your privacy is guaranteed."}}]}</script>
</head>
<body>
  <div class="page-wrapper">
    <header class="site-header"><a href="index.html" class="site-logo"><span class="icon">⚡</span> QuickTools</a><nav class="site-nav"><a href="index.html">All Tools</a></nav></header>
    <div class="ad-zone ad-zone-top">Ad Space — 728×90</div>
    <div class="tool-header"><div class="tool-badge">💰 Finance</div><h1>Compound Interest Calculator</h1><p>Calculate investment growth with compound interest and monthly contributions.</p></div>
    <div class="tool-card">
      <div class="controls-row">
        <div class="control-group"><label>Initial Investment ($)</label><input type="number" id="principal" value="10000" min="0" step="1000" oninput="calc()"></div>
        <div class="control-group"><label>Monthly Contribution ($)</label><input type="number" id="monthly" value="500" min="0" step="50" oninput="calc()"></div>
        <div class="control-group"><label>Annual Rate (%)</label><input type="number" id="rate" value="8" min="0" max="30" step="0.5" oninput="calc()"></div>
        <div class="control-group"><label>Years</label><input type="number" id="years" value="20" min="1" max="50" oninput="calc()"></div>
      </div>
      <div class="controls-row mt-1">
        <div class="control-group"><label>Compound</label><select id="compound" onchange="calc()"><option value="12" selected>Monthly</option><option value="4">Quarterly</option><option value="1">Annually</option><option value="365">Daily</option></select></div>
      </div>
    </div>
    <div class="tool-card" style="text-align:center;">
      <div style="display:grid;grid-template-columns:1fr 1fr 1fr;gap:1rem;">
        <div><div class="text-muted" style="font-size:0.8rem;">Total Balance</div><div id="total" style="font-size:2rem;font-weight:700;color:var(--success);">$0</div></div>
        <div><div class="text-muted" style="font-size:0.8rem;">Total Contributions</div><div id="contributions" style="font-size:2rem;font-weight:700;">$0</div></div>
        <div><div class="text-muted" style="font-size:0.8rem;">Interest Earned</div><div id="interest" style="font-size:2rem;font-weight:700;color:var(--accent-hover);">$0</div></div>
      </div>
    </div>
    <div class="tool-card">
      <h3 style="font-size:0.95rem;margin-bottom:0.75rem;">📊 Growth Over Time</h3>
      <canvas id="chart" style="width:100%;height:250px;"></canvas>
    </div>
    <div class="tool-card">
      <h3 style="font-size:0.95rem;margin-bottom:0.75rem;">📋 Year-by-Year</h3>
      <div id="table" style="max-height:300px;overflow-y:auto;font-size:0.82rem;"></div>
    </div>
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    <div class="related-tools"><h2>Related Tools</h2><div class="related-grid"><a href="loan-calculator.html"><span class="tool-icon">🏦</span> Loan Calculator</a><a href="salary-calculator.html"><span class="tool-icon">💰</span> Salary Calculator</a><a href="percentage-calculator.html"><span class="tool-icon">🧮</span> Percentage</a><a href="discount-calculator.html"><span class="tool-icon">🏷️</span> Discount</a></div></div>

        <div class="tool-card" style="max-width:720px;">
      <h2 style="font-size:1rem;margin-bottom:0.75rem;">📖 About Compound Interest Calculator</h2>
      <p style="font-size:0.85rem;line-height:1.7;color:var(--text-muted);margin-bottom:0.75rem;">Compound Interest Calculator is a free, browser-based tool designed for students, professionals, and anyone who needs quick calculations. Calculate compound interest on investments and savings. See growth over time with monthly contributions. Compare interest rates. Free online compound interest calculator. Everything runs locally in your browser using JavaScript — no data is ever sent to a server, making it completely private and secure. The tool is designed to be intuitive and beginner-friendly while still offering advanced features for power users. It loads instantly with no installation required and works offline once loaded. Use it as often as you need — there are no daily limits, no watermarks, and no hidden fees.</p>
      <h3 style="font-size:0.9rem;margin-bottom:0.5rem;">How to Use</h3>
      <ol style="font-size:0.85rem;color:var(--text-muted);line-height:1.7;padding-left:1.2rem;">
        <li>Enter or paste your data in the input area above.</li>
        <li>Adjust settings and options to match your needs.</li>
        <li>View the results instantly — they update in real-time.</li>
        <li>Copy, download, or share your output with one click.</li>
      </ol>
    </div>
    <div class="tool-card faq-section">
      <h2 style="font-size:1.1rem;margin-bottom:1rem;">❓ Frequently Asked Questions</h2>
      <details style="margin-bottom:0.75rem;border-bottom:1px solid var(--border);padding-bottom:0.75rem;"><summary style="font-weight:600;cursor:pointer;font-size:0.9rem;">Is Compound Interest Calculator free to use?</summary><p style="margin-top:0.5rem;font-size:0.85rem;color:var(--text-muted);line-height:1.6;">Yes! Compound Interest Calculator is completely free with no signup required. It runs entirely in your browser — your data never leaves your device.</p></details>
      <details style="margin-bottom:0.75rem;border-bottom:1px solid var(--border);padding-bottom:0.75rem;"><summary style="font-weight:600;cursor:pointer;font-size:0.9rem;">How do I use Compound Interest Calculator?</summary><p style="margin-top:0.5rem;font-size:0.85rem;color:var(--text-muted);line-height:1.6;">Simply enter your values in the input fields above and the results update instantly. No button clicks needed — everything calculates in real-time.</p></details>
      <details style="margin-bottom:0.75rem;border-bottom:1px solid var(--border);padding-bottom:0.75rem;"><summary style="font-weight:600;cursor:pointer;font-size:0.9rem;">Is my data safe with Compound Interest Calculator?</summary><p style="margin-top:0.5rem;font-size:0.85rem;color:var(--text-muted);line-height:1.6;">Absolutely. Compound Interest Calculator runs 100% client-side in your browser using JavaScript. No data is uploaded, stored, or shared with any server. Your privacy is guaranteed.</p></details>
    </div>
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    <footer class="site-footer"><p>&copy; 2026 QuickTools.</p><div class="footer-links"><a href="index.html">All Tools</a><a href="#">Privacy</a></div></footer>
  </div>
  <script>
    function fmt(n){return'$'+n.toLocaleString('en-US',{minimumFractionDigits:0,maximumFractionDigits:0});}
    function calc(){
      const P=+document.getElementById('principal').value||0;const m=+document.getElementById('monthly').value||0;
      const r=+document.getElementById('rate').value/100;const y=+document.getElementById('years').value||1;
      const n=+document.getElementById('compound').value;
      const yearData=[];let balance=P;
      for(let yr=1;yr<=y;yr++){
        for(let mo=0;mo<12;mo++){balance+=m;balance*=(1+r/n)**(n/12);}
        const totalContrib=P+m*12*yr;
        yearData.push({year:yr,balance,contributions:totalContrib,interest:balance-totalContrib});
      }
      const final=yearData[yearData.length-1];
      document.getElementById('total').textContent=fmt(final.balance);
      document.getElementById('contributions').textContent=fmt(final.contributions);
      document.getElementById('interest').textContent=fmt(final.interest);
      // Chart
      const canvas=document.getElementById('chart');const ctx=canvas.getContext('2d');
      canvas.width=canvas.clientWidth;canvas.height=250;
      ctx.clearRect(0,0,canvas.width,canvas.height);
      const maxVal=final.balance;const barW=(canvas.width-60)/y;
      yearData.forEach((d,i)=>{
        const x=40+i*barW;const contH=(d.contributions/maxVal)*(canvas.height-40);const totalH=(d.balance/maxVal)*(canvas.height-40);
        ctx.fillStyle='rgba(99,102,241,0.3)';ctx.fillRect(x,canvas.height-30-totalH,barW-2,totalH);
        ctx.fillStyle='rgba(99,102,241,0.7)';ctx.fillRect(x,canvas.height-30-contH,barW-2,contH);
        if(y<=20||i%5===0){ctx.fillStyle='rgba(255,255,255,0.5)';ctx.font='10px monospace';ctx.fillText(d.year,x,canvas.height-18);}
      });
      // Table
      document.getElementById('table').innerHTML='<div style="display:grid;grid-template-columns:60px 1fr 1fr 1fr;gap:2px;font-weight:600;padding:4px;border-bottom:2px solid var(--border);"><span>Year</span><span>Balance</span><span>Contributions</span><span>Interest</span></div>'+
        yearData.map(d=>`<div style="display:grid;grid-template-columns:60px 1fr 1fr 1fr;gap:2px;padding:4px;border-bottom:1px solid var(--border);"><span>${d.year}</span><span style="color:var(--success);">${fmt(d.balance)}</span><span>${fmt(d.contributions)}</span><span style="color:var(--accent-hover);">${fmt(d.interest)}</span></div>`).join('');
    }
    calc();
  </script>
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</body>
</html>