Your question depends on when you plan to retire, how many years you live past your retirement age and if that is your only source (ignoring social security among others). You also should keep in mind that you may not have certain expenses (mortgage) at retirement. So I am making the assumption that your expenses equal your salary (now and at retirement) since I don't know what your expenses are or what your other retirement benefits might be. This as a two period calculation - (1) the period up to the time you retire and (2) your retirement period. You would have to have $353,470 today to be able to retire at 65 and here is how it was calculated. First you need to know what the equivalent to your expenses (I am assuming $42K) will be when you turn 65 which is about $77,865 (due to inflation of 2.5% per year). You can use the future value tool in Excel =FV(0.025,25,0,-42000)or plug in the formula =42000*(1.025)^25 into an Excel cell. Then you take that figure and make some assumptions (inflation will be 2.5%, the money you earn on your investment will be 7.5% - an effective rate of 5%). So if you take the present value of $77,865 payments with the amount of years of retirement (say 30) at an effective rate (interest rate less inflation)of 5% you get a figure of $1,196,975 that you would need at retirement (65 years of age). The formula in Excel =PV(0.05,30,-77865,0). To determine what you need today you now you take the $1,196,975 you need at retirement and find the present value using the same assumptions related to interst and inflation (so an effective rate of 5%) and the 25 year period (40-65). The present value would then be $353,470. The formula in Excel would be =PV(0.05,25,0,-1196975). I've included the formulas in case your want to play with the numbers. Remember that if inflation is more than 2.5% or the amount you earn on investments falls below 7.5% then the amount you need will increase and vice versa. If you want some examples on how to calculate your expenses this is a good link. http://marriottschool.byu.edu/marriottmag/winter06/features/atwork1.cfm?loc=feature If you want a simple calculator go to the link below (I think they are much more conservative in terms of what your effective rate (return you earn - inflation) would be on investments). http://cgi.money.cnn.com/tools/retirementneed/retirementneed_plain.html Hope this help.