Annuity Calculator
An annuity calculator determines the regular payments from a lump sum investment or the lump sum needed to generate desired payments. Annuities convert savings into guaranteed income streams.
Annuity Payment Formula
Payment = Principal × (r × (1+r)^n) / ((1+r)^n - 1)
Where r = periodic rate, n = number of periods
Annuity Payments from Lump Sum
At 5% annual rate:
| Lump Sum | 10 Years | 15 Years | 20 Years | 25 Years | $100,000$12,950/yr$9,634/yr$8,024/yr$7,095/yr $250,000$32,375/yr$24,085/yr$20,060/yr$17,738/yr $500,000$64,750/yr$48,170/yr$40,120/yr$35,476/yr | $1,000,000 | $129,500/yr | $96,340/yr | $80,240/yr | $70,952/yr |
Annuity Calculator Implementation
``javascript
function calculateAnnuityPayment(principal, rate, years) {
const r = rate / 100;
const n = years;
// Annuity payment formula
const payment = principal * (r * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) - 1);
return {
annualPayment: payment.toFixed(2),
monthlyPayment: (payment / 12).toFixed(2),
totalPayments: (payment * years).toFixed(2),
interestEarned: ((payment * years) - principal).toFixed(2)
};
}
function calculateLumpSumNeeded(desiredPayment, rate, years) {
const r = rate / 100;
const n = years;
const lumpSum = desiredPayment * (Math.pow(1 + r, n) - 1) / (r * Math.pow(1 + r, n));
return {
lumpSumNeeded: lumpSum.toFixed(2),
desiredPayment,
years
};
}
console.log(calculateAnnuityPayment(500000, 5, 20));
// { annualPayment: '40120', monthlyPayment: '3343.33' }
``
Types of Annuities
Immediate annuities start payments right away. Deferred annuities grow tax-deferred before payouts begin. Fixed annuities guarantee rates; variable annuities tie to investments.