Compound Interest CalculatorWali Khan Kakar — Compound Interest CalculatorCompound Interest Calculator
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Financial Tool
Compound Interest
Calculator
Model your wealth growth in any currency — see the true power of compounding over time.
Investment Parameters
💰
Investment Details
📈
Growth Parameters
Results
📊
Fill in your parameters above and click
Calculate Returns to see your projection.
Total Invested
—
Principal + Contributions
Export Report
Download Your Report
Export your full calculation with year-by-year breakdown in your preferred format
Yearly Breakdown
Year-by-Year Breakdown
| Year | Balance | Total Invested | Interest Earned | Yearly Growth |
|---|
';var blob = new Blob(['\ufeff' + html], { type:'application/msword' });
var url = URL.createObjectURL(blob);
var a = document.createElement('a');
a.href = url; a.download = 'Compound-Interest-Report.doc';
a.click(); URL.revokeObjectURL(url);
showToast('✅ Word document downloaded!');
};// ── Excel Download ──
window.wkkDownloadExcel = function() {
if (!wkkData.length) { showToast('Please calculate first!'); return; }
var p = getParams();
var final = wkkData[wkkData.length-1];
var interest = final.balance - final.invested;
var ret = ((final.balance - final.invested) / final.invested * 100).toFixed(1);var wb = XLSX.utils.book_new();var s1 = [
['COMPOUND INTEREST REPORT — WaliKhanKakaro.com','','',''],
['Generated:', new Date().toLocaleDateString(),'',''],
['','','',''],
['PARAMETERS','','',''],
['Currency', p.currency+' ('+p.symbol+')', 'Principal', p.principal],
['Monthly Contrib.', p.monthly, 'Period (Years)', p.years],
['Interest Rate (%)', p.rate, 'Compounding', p.frequency],
['Inflation (%)', p.inflation,'',''],
['','','',''],
['RESULTS','','',''],
['Total Future Value', final.balance, 'Total Invested', final.invested],
['Interest Earned', interest, 'Total Return (%)', parseFloat(ret)]
];
var ws1 = XLSX.utils.aoa_to_sheet(s1);
ws1['!cols'] = [{wch:24},{wch:22},{wch:24},{wch:22}];
XLSX.utils.book_append_sheet(wb, ws1, 'Summary');var hdr = ['Year','Balance ('+p.symbol+')','Total Invested ('+p.symbol+')','Interest Earned ('+p.symbol+')','Yearly Growth ('+p.symbol+')'];
var rows = wkkData.map(function(r){ return [r.year, r.balance, r.invested, r.interest, r.growth]; });
var ws2 = XLSX.utils.aoa_to_sheet([hdr].concat(rows));
ws2['!cols'] = [{wch:8},{wch:22},{wch:22},{wch:22},{wch:18}];
var range = XLSX.utils.decode_range(ws2['!ref']);
for (var R = 1; R <= range.e.r; R++) {
for (var C = 1; C <= 4; C++) {
var cell = ws2[XLSX.utils.encode_cell({r:R, c:C})];
if (cell) { cell.t = 'n'; cell.z = '#,##0.00'; }
}
}
XLSX.utils.book_append_sheet(wb, ws2, 'Year-by-Year');var hdr3 = ['Year','Balance','Invested','Interest'];
var rows3 = wkkData.map(function(r){ return [r.year, Math.round(r.balance), Math.round(r.invested), Math.round(r.interest)]; });
var ws3 = XLSX.utils.aoa_to_sheet([hdr3].concat(rows3));
ws3['!cols'] = [{wch:8},{wch:18},{wch:18},{wch:18}];
XLSX.utils.book_append_sheet(wb, ws3, 'Chart Data');XLSX.writeFile(wb, 'Compound-Interest-Report.xlsx');
showToast('✅ Excel file downloaded!');
};// ── Init ──
function wkkInit() {
// Re-grab elements after DOM is confirmed ready
yI = document.getElementById('wkkYears');
yS = document.getElementById('wkkYearsSlider');
rI = document.getElementById('wkkRate');
rS = document.getElementById('wkkRateSlider');if (yI) { yI.addEventListener('input', function(){ yS.value = yI.value; wkkCalculate(); }); }
if (yS) { yS.addEventListener('input', function(){ yI.value = yS.value; wkkCalculate(); }); }
if (rI) { rI.addEventListener('input', function(){ rS.value = rI.value; wkkCalculate(); }); }
if (rS) { rS.addEventListener('input', function(){ rI.value = rS.value; wkkCalculate(); }); }['wkkPrincipal','wkkMonthly','wkkFreq','wkkInflation'].forEach(function(id){
var el = document.getElementById(id);
if (el) el.addEventListener('input', wkkCalculate);
});wkkCalculate();
}if (document.readyState === 'loading') {
document.addEventListener('DOMContentLoaded', wkkInit);
} else {
wkkInit();
}})();