This calculator determines how many years a lump sum investment will last with repeated fixed monthly withdrawals. For example, if an investor has $100,000 invested at 6.2% annual fixed interest and wishes to withdraw a fixed amount of $1000 per month, how many years will it take for the balance to be $0. To use this calculator for a fixed withdrawal amount, let the annual COLA equal 0%. If you wish to adjust your monthly withdrawal amount by 3% per annum, set the COLA equal 3%, etc.