<prompt> Human: My dad, who is retiring very well, would always tell me if I put 10 of my take home salary into a 401kIRA type of retirement fund, and started in my 20s, Id have plenty of money to retire on. Im 36 with 40k saved for retirement, and the various online retirement calculators show Im only hitting 66-70 of the goal amount needed to retire at 65-70 and still be able to live on means equivalent to my current salary.Specifically, Ive been using 80k as an approximation of what I expect my income to be, and using 10 take home as the portion going to the retirement account. Im in the US and plan on having no other retirement sources of income besides the IRA and whatever SS gives me.Do you think my estimate of save 10 take home is a good rule of thumb or should I rethink my course?edit : Thanks for the replies all. I really havent done an excellent job of saving for retirement. I will definitely make it a goal to contribute 15-20. Luckily Im in a career field that doesnt require any real physical exertion, so working past traditional retirement age is an option, even if its not my preference.  <response>: I think 10 is a good minimum, if we make big assumptions about average performance and lifestyle, etc. Youll have more than the average American, but thats not much of an accomplishment. 10 should mean you wont starve or have to make major compromises, especially with SS factored in. I would and do say that 15 gets most people enough to have a good retirement.Also, the exactly when you started saving makes a difference since time is a big factor. If you saved 10 starting at 22, you should have about 125 of your total salary saved up by age 36 and thats with no gains. To meet the benchmark of having 100 by age 35, you needed to start at 25. So if you started after 25, Id say you are a little behind and want to contribute more than 10 anyway.edit: Also, you may already know this, but if you assume a 80k salary but give 10 to retirement, your full retirement income is 72k, since you know you can cut out retirement as an expense. 