The amount it takes to retire depends primarily upon two factors -- how expensively you plan to live and how many monthly payments you have. There are, of course, other factors like where you live, etc., but I think these are the main two. I wrote a book a few years ago entitled "Retire and Travel for $1000 a Month" -- Click here to go read it online. My wife claims she could write a rebuttal demonstrating how no sane person would try it for $1000 per month. I explain in the book, however, what this entails. I provide a budget, showing the actual expenses when we tried this for about 5 months. If you read it and decide you can't live with the restrictions, then $1000 a month isn't enough for you. Also, I forgot about a couple of things which may be significant for you, as explained on the More on RV Travel page. I also included many updated ideas in the sequel "Retire and Travel - 20 Years Later." Click here to read about it and/or purchase a copy. Finally, you can see the opinions and experience of website viewers summarized in my Retirement Survey.
One thing that I think is often overlooked when thinking of retiring is that your retirement years are generally quite different from what you envisioned. I retired thinking that I might get some part-time work at RV campgrounds, maybe sell a few things at flea markets now and then, but generally just spend time wandering the country in our RV. I had no idea that I'd get that consulting job and my retirement would have been significantly different without it. Life is full of surprises and most of mine have been positive ones. My advice to anyone is to retire as soon as you are able to pay off most debts and think you might have enough to survive on. If you don't have enough, you can always "unretire" - check out my advice in that area by clicking on the menu choice "Unretirement Tips". I've seen several situations where a friend has delayed their retirement too long, than are met with serious illness or death soon after their long-postponed retirement. I'd rather retire earlier and maybe have a few hard times, than to postpone too long and not get any enjoyment out of my "golden" years.
When I did a search (in Yahoo!) on "retire", I got 550,000 webpage hits. I obviously can't say that I perused them all, but I've spent many hours wandering through many of them. One thing I've found is that there are many people out there who have spent much more time than I on the question of how much it takes to retire. I've done spreadsheets that assume a reasonable rate of return on your IRA and a specific monthly allowance, but some of the sites I found have complete programs dedicated to the questions. Take a look at some of the following and pick the one you like best -- they each have their own ideas on how to "size your stake".
2017 Add-on: The "last time" mentioned above was 1999. We had just over $200K in an IRA and it took a little hit around 2001. I also was able to get hired as a consultant at the company from which I retired, continuing to draw some good pay for 14 years. Now, 18 years later, my wife and I are living in a condo in South Florida, surviving totally on Social Security and my website business/hobby. Only possible, I think, because we were able to pay off house, cars, etc. Only bills now are every day living expenses, condo fees, taxes, and ... of course ... the occasional "unexpected emergency." Not saying my retirement advice is necessarily correct for all, but it worked pretty well for us.
Click the graphic to go to Northwestern Mutual's Lifespan Calculator. Answer 13 questions and you'll know how long to plan your retirement.
HOW MUCH DO I NEED?
First, you get my opinion. What are my credentials? Well, I've retired four times, going back to work each time except the last time. This could either be viewed as "experienced, therefore can give advice" or "hasn't gotten it right in 3 tries, therefore shouldn't give advice". I'll go with the former and give some advice. You, of course, can ignore it or follow it, as you wish. Also, I wasn't real serious about staying out until this last time.