Amortization-Based Withdrawal Calculator
Calculate sustainable retirement spending that adjusts to market conditions. Based on Robert Merton’s optimal consumption framework. Learn more below.
Your Inputs
$
1 to 50 years
%
Think of this as a throttle for how fast you spend down your portfolio. A higher rate pushes more money to your current self; a lower rate preserves more for your future self. It is not “withdraw X% of your portfolio.” How this works →
%
Annual inflation rate (used for Nominal/Real toggle)
$
$0 to fully deplete, or higher to leave a legacy.
Advanced Options
How your spending grows relative to inflation. Affects Year 1 withdrawal amount.
%
Only used if Custom is selected above.
$
Essential expenses in today’s dollars. Automatically grows with inflation. Applied in Years 2-30 only.
💡 How this works:
ABW recalculates your withdrawal each year using the PMT formula with your current balance and remaining years. Historical Backtesting tests every actual sequential period from 1871-2024 to preserve real crash sequences. Bootstrap randomly samples from the same historical data to create 1,000 new sequences. Custom lets you enter your own return and volatility assumptions.
ABW recalculates your withdrawal each year using the PMT formula with your current balance and remaining years. Historical Backtesting tests every actual sequential period from 1871-2024 to preserve real crash sequences. Bootstrap randomly samples from the same historical data to create 1,000 new sequences. Custom lets you enter your own return and volatility assumptions.
Your Results
Ready to Calculate
Enter your details and click calculate to see how much you can safely withdraw this year.