What This Calculator Does
When you reach retirement and have a lump sum saved, the next question becomes: how much can I withdraw each month without running out of money? An annuity payout calculator answers exactly that. It calculates the fixed monthly payment you can receive from a given principal over a specific time period.
This calculator is the distribution phase counterpart to the annuity savings calculator. It is useful for modeling income from retirement savings, insurance annuities, structured settlements, or any scenario involving periodic withdrawals from a lump sum.
Inputs Required
- Annuity Principal: The starting lump sum balance
- Annual Interest Rate: The rate earned on the remaining balance during the payout phase
- Payout Duration: How many years the payments will last
Outputs Provided
- Monthly Payout: The fixed amount you receive each month
- Total Payout: The total amount received over the full term
- Total Interest Received: Interest earned on the balance during the payout phase
- Balance Depletion Chart: Year by year view of how the balance decreases and total withdrawals accumulate
How the Calculation Works
The annuity payout uses the same present value formula as loan amortization. The principal earns interest each month, and the withdrawal covers that interest plus a portion of the principal. The formula ensures the balance reaches exactly zero at the end of the term.
PMT = PV x [r x (1 + r)^n] / [(1 + r)^n - 1]
- PMT is the monthly payout
- PV is the present value (starting principal)
- r is the monthly rate (annual rate divided by 12)
- n is the total number of monthly payments
Early in the payout phase, most of each payment consists of interest. Over time, as the balance decreases, the interest portion shrinks and the principal portion grows, mirroring loan amortization in reverse.
How to Use the Calculator
- Enter the total amount you have saved or will receive as a lump sum
- Set the expected annual interest rate the balance will earn during payouts
- Choose how many years you want the income to last
- Review your monthly payout and total lifetime income
- Use the chart to see how quickly your balance decreases over time
Example Calculation
Starting with $300,000, a 5% annual return, and a 20-year payout term:
- Monthly payout: approximately $1,980
- Total received over 20 years: approximately $475,000
- Interest earned during payout phase: approximately $175,000
The $175,000 in interest earned while drawing down the balance means you receive significantly more than the original $300,000 in total payments. Without any interest, the same principal would last only 12.6 years at the same monthly withdrawal amount.
Real World Scenarios
Retiree Planning Income
Carl has $500,000 in retirement savings and wants income for 25 years. At a 4.5% return, this calculator tells him exactly how much he can withdraw monthly without depleting the account before age 90. He can adjust the return rate or duration to stress-test different scenarios.
Structured Settlement
Someone receiving a $200,000 legal settlement and considering converting it to monthly income over 15 years can use this calculator to see the monthly payment they would receive versus investing the lump sum independently.
Comparing Annuity Insurance Products
Before purchasing an insurance annuity product, use this calculator to verify whether the quoted monthly payment matches what you should receive for the premium amount. If the insurer's offer is significantly below the calculated amount, the product may include high fees or a low implied interest rate.
Why This Calculation Matters
One of the biggest risks in retirement is outliving your savings. Knowing exactly how long your money will last at a given withdrawal rate empowers you to make deliberate decisions about spending, investment strategy, and when to begin drawing down different accounts.
The interest rate earned during the payout phase has a massive impact on how long your money lasts. Even a 1% difference in return rate can add years to the life of your savings. This calculator makes that visible.
Common Mistakes to Avoid
- Not accounting for inflation: A fixed payout will buy less over time. Consider whether your monthly income keeps pace with rising expenses
- Assuming too high a return: Conservative payout phase returns (3% to 5%) are safer than assuming continued high-growth equity returns
- Ignoring taxes: Withdrawals from traditional retirement accounts and annuities are generally taxable. Your net monthly income will be less than the gross payout shown
- Not leaving a buffer: Planning to deplete the account exactly at life expectancy leaves no margin for a longer life. Consider adding 5 to 10 years to your payout duration