So we’ve all heard that “if you save and invest ‘X dollars’ every year starting at ‘age Y’ you’ll be a millionaire”.  How much will your retirement nest egg amount to at age 45? 55? 65?  Find out in seconds through this predictive simulation calculator!

Instructions:

  1. Click “Run Pen” to activate the interactive Pen
  2. Once activated, enter your current age, starting balance, and yearly contribution
  3. Click “Simulate Again” for a new simulation

The assumptions are as follows:

  • Rate of Return is calculated via =norm.dist(RAND(),mean,std dev) function to help simulate variability
  • Annual return is normally distributed with a mean of 1.06 (6% annual gain) and .13 standard deviation (95% (+/- 2std dev) of all years will be between -20% and +32%)
  • In today’s dollars, 6% real return as n approaches infinity
  • n = 50 simulations
  • Percentiles will create a decent interquartile range
  • Front-loaded annually

If you notice errors or have any questions or comments, please contact me here.

Happy Simulating!


  • rand() function inspired by MITx SC0x – Week 6, Slide 16
  • DISCLAIMER: This calculator is only a rough estimation, and not a crystal ball into the future.