How do 401k handle rate of return
"Your employer sends the money that you choose to contribute, plus employer match if any, to the administrator of the 401k plan who invests the money as you have directed, choosing between the alternatives offered by the administrator. Typically, the alternatives are several different mutual funds with different investment styles, e.g. a S&P 500 index fund, a bond fund, a money-market fund, etc.  Now, a statement such as ""I see my 401k is up 10%"" is meaningless unless you  tell us how you are making the comparison. For example, if you have just started employment and $200 goes into your 401k each month and is invested in a money-market fund (these are paying close to 0% interest  these days), then your 11th contribution increases your  401k from $2000 to $2200 and your 401k is ""up 10%"". More generally, suppose for simplicity that all the  401k investment is in just one (stock) mutual fund and that you own 100 shares of the fund as of right now.  Suppose also that your next contribution will not occur for three weeks when you get your next paycheck, at which time additional shares of the mutual fund will be purchased Now, the value of the mutual fund shares (often referred to as net asset value or NAV) fluctuates as stock prices rise and fall, and so the  401k balance = number of shares times NAV changes in accordance with these fluctuations. So,  if the NAV increases by 10% in the next two weeks, your 401k balance will have increased by 10%.  But you still own only 100 shares of the mutual fund. You cannot use the 10% increase  in value to buy more shares in the mutual fund  because there is no money to pay for the additional shares  you wish to purchase.  Notice that there is no point selling some of the shares (at the 10% higher NAV) to get cash  because you will be purchasing shares at the higher NAV too. You could, of course, sell shares of the stock mutual fund at the higher NAV and buy shares of some other fund available to you in the 401k plan.  One advantage of doing this inside the 401k plan is that you don't have to pay taxes (now) on the 10% gain that you have made on the sale. Outside tax-deferred plans such as 401k and IRA plans, such gains would be taxable in the year of the sale.  But note that selling the shares of the stock fund and buying something else indicates that you believe that the NAV of your stock mutual fund is unlikely to increase any further in the near future. A third possibility for your 401k being up by 10% is that the mutual fund paid a dividend or made a capital gains distribution in the two week period that we are discussing.  The NAV falls when such events occur, but if you have chosen to reinvest the dividends and capital gains, then the number of shares that you own goes up.  With the same example as before, the NAV goes up 10% in two weeks at which time a capital gains distribution occurs, and so the NAV falls back to where it was before.  So, before the capital gains distribution, you owned 100 shares at $10 NAV which went up to $11 NAV (10% increase in NAV) for a net increase in 401k balance from $1000 to $1100. The mutual fund distributes capital gains in the amount of $1 per share sending the NAV back to $10, but you take the $100 distribution and plow it back into the mutual fund, purchasing 10 shares at the new $10 NAV.  So now you own 110 shares at $10 NAV (no net change in price in two weeks) but your 401k balance is $1100, same as it was before the capital gains distribution and you are up 10%.  Or, you could have chosen to invest the distributions into, say, a bond fund available in your 401k plan and still be up 10%, with no change in your stock fund holding, but a new investment of $100 in a  bond fund. So, being up 10% can mean different things and does not necessarily mean that the ""return"" can be used to buy more shares." A 401(k) is an investment just like any other investment. You generally get two types of return lumped into that number, but there can be more and you should read your funds prospectus carefully. If you aren't investing in direct companies, you're using mutual funds for instance, then you should read the funds prospectus to see how they handle these situations for the underlying securities they hold for you. Although I think this is the basic answer to the question as you asked.
Growth in a 401k dodges taxes, which means more of the gains get reinvested. Effectively, it's a boosted return rate. Like any investment, a 401k can lose value. During the period before retirement, lower stock and bond prices actually help you buy more shares than you could if prices were high, so the real question is what the funds are doing at the time you start pulling money back out. That concern is why investors generally, not just 401k investors, should change their investment mix over time, to balance oossible risk against time to recover and possible reward.  And if your employer matches 401k contributions to any degree, that too improves your effective gains and buffers you against some of ghe risk. Hence the general advice that if you don't fund your 401k at least enough to max out the company match, you're leaving free money on the table. "You can move money from a 403b to a 401k plan, but the question you should ask yourself is whether it is a wise decision. Unless there are specific reasons for wanting to invest in your new employer's 401k (e.g. you can buy your employer's stock at discounted rates within the 401k, and this is a good investment according to your friends, neighbors, and brothers-in-law), you would be much better off moving the 403b money into an IRA, where you have many more choices for investment and usually can manage to find investments with lower investment costs (e.g. mutual fund fees) than in a typical employer's 401k plan. On the other hand, 401k assets are better protected than IRA assets in case you are sued and a court finds you to be liable for damages; the plaintiff cannot come after the 401k assets if you cannot pay.  To answer the question of ""how?"", you need to talk to the HR people at your current employer to make sure that they are willing to accept a roll-over from another tax-deferred plan (not all plans are agreeable to do this) and get any paperwork from them, especially making sure that you find out where the check is to be sent, and to whom it should be payable. Then, talk to your previous employer's HR people and tell them that you want to roll over your 403b money into the 401k plan of your new employer, fill out the paperwork, make sure they know to whom to cut the check to, and where it is to be sent etc. In my personal experience, I was sent the check payable to the custodian of my new (IRA) account, and I had to send it on to the custodian; my 403b people refused to send the check directly to the new custodian. The following January, you will receive a 1099-R form from your 403b plan showing the amount transferred to the new custodian, with hopefully the correct code letter indicating that the money was rolled over into another tax-deferred account." A couple ideas: Use excel - it has an IRR (internal rate of return) that can handle a table of inputs as you describe, along with dates deposited to give you a precise number.  Go simple - track total deposits over the year, assume half of that was present in January. So, for example, your account started the year with $10k, ended with $15k, but you deposited $4k over the year. It should be clear the return (gain) is $1k, right? But it's not 10%, as you added during the year. I'd divide $1k/$12k for an 8.3% return. Not knowing how your deposits were structured, the true number lies between the 10% and 6.7% as extremes. You'll find as you get older and have a higher balance, this fast method gaining accuracy, as your deposits are a tinier fraction of your account and likely spread out pretty smoothly over the year anyway. Why would you want to withdraw only the company match, and presumably leave your personal contributions sitting in your ex-company's 401k plan? Generally, 401k plans have larger annual expenses and provide for poorer investment choices than are available to you if you roll over your 401k investments into an IRA. So, unless you have specific reasons for wanting to continue to leave your money in the 401k plan (e.g. you have access to investments that are not available to nonparticipants and you think those investments are where you want your money to be), roll over part (or all) of your 401k assets into an IRA, and withdraw the rest for personal expenses.  If your personal contributions are in a Roth 401k, roll them over to a Roth IRA, but, as I remember it, company contributions are not part of the Roth 401k and must be rolled over into a Traditional IRA. Perhaps this is why you want to take those in cash to pay for your personal purchase? Also, what is this 30% hit you are talking about? You will owe income tax on the money withdrawn from the 401k (and custodians traditionally withhold 20% and send it to the IRS on your behalf) plus penalty for early withdrawal (which the custodian may also withhold if you ask them), but the tax that you will pay on the money withdrawn will depend on your tax bracket, which may be lower if you are laid off and do not immediately take on a new job. That is, the 30% hit may be on the cash flow, but you may get some of it back as a refund when you file your income tax return. "401(k) doesn't have a ""return rate"", because 401(k) is not a type of investment -- it is a vehicle for investment, with certain tax treatments. Just like your money that's not in a 401(k), you can invest it in either the bank, a CD, stocks, mutual funds, bonds, etc., you can similarly (depending on the options given to you by your 401(k) plan) invest the money in the 401(k) in a cash account, buy stocks, mutual funds, etc. Your return is dependent on how you invest your money, not whether it's in a 401(k) or not. Whether it's in a (Roth or Traditional) 401(k) simply affects when and how it gets taxed. (It is true that most 401(k) plans offer little variety in types of investments you can choose; however, this is not a big deal, as chances are that in a few years, you will leave your company, at which point you are able to rollover the 401(k) into an IRA, at which point you will have many, many options for how to invest it.) To make a valid comparison, you should be comparing the same type of investment in both cases. That means, you should assume the same return for both the money outside the 401(k), and the money inside the 401(k), and only consider the taxes and penalties (if you plan to withdraw early)." WRONG. Assuming each account has the same investment option the rate of return is not dependent on the initial amount of money in the account, but rather the allocation amongst said investment. Suppose based on your investment allocation in either account you gain 10% interest over the year.  In the first scenario your ending balance will be (30000+4800)*1.10 = $38,280.  In the second scenario your first account will be worth 30000*1.10 = $33,000, and the second account will be worth 4800*1.10 = 5280, for a total of 33000+5280 = $38,280. It essentially works the same. Some states don't have any income taxes at all (like Florida or Wyoming), some only tax income derived in the state, and some tax worldwide income (like New York or California), similarly to the Federal income taxes. However, if you're living abroad (i.e.: you're a citizen or resident of a foreign country and you live there), you're not considered resident by most of the states (check with your state for specific definitions) for most, if not all, the time of your residency abroad. In such case - you don't pay state taxes, only Federal. You have to remember that foreign income exclusion doesn't apply to the income from your 401k, so you pay the taxes as if you're in the US. You can not use foreign taxes credit as well (but depending on the tax treaty with the country you're moving to, your 401k income might not be taxable there). In some cases you may end up with double taxation: US will tax your 401k income as you're a US citizen and the income is derived from the US sources, and the foreign country will tax the income based on its own laws. This is not a tax advice, and this answer was not intended or written to be used, and it cannot be used by any taxpayer, for the purpose of avoiding penalties that may be imposed on the taxpayer. You can borrow against a 401k for 5 years. This defers any penalty fees that the IRS mandates. Put the cash back in your 401k within those 5 years. you can also solo administer 401k plans even if you have an unincorporated business, so you can start one of those if you have any other form of cashflow, and there may be a way to get the other plan rolled into your solo one.  http://www.irs.gov/publications/p560/ch04.html#en_US_publink10009053