Do overall 401(k) contribution limits sum across employers?
Let me first start off by saying that you need to be careful with an S-Corp and defined contribution plans.  You might want to consider an LLC or some other entity form, depending on your state and other factors. You should read this entire page on the irs site:  S-Corp Retirement Plan FAQ, but here is a small clip: Contributions to a Self-Employed Plan You can’t make contributions to a self-employed retirement plan from your S corporation   distributions. Although, as an S corporation shareholder, you receive   distributions similar to distributions that a partner receives from a   partnership, your shareholder distributions aren’t earned income for   retirement plan purposes (see IRC section 1402(a)(2)). Therefore, you   also can’t establish a self-employed retirement plan for yourself   solely based on being an S corporation shareholder. There are also some issues and cases about reasonable compensation in S-Corp.  I recommend you read the IRS site's S Corporation Compensation and Medical Insurance Issues page answers as I see them, but I recommend hiring CPA You should be able to do option B.  The limitations are in place for the two different types of contributions:  Elective deferrals and Employer nonelective contributions.  I am going to make a leap and say your talking about a SEP here, therefore you can't setup one were the employee could contribute (post 1997). If your doing self employee 401k, be careful to not make the contributions yourself. If your wife is employed the by company, here calculation is separate and the company could make a separate contribution for her. The limitation for SEP in 2015 are 25% of employee's compensation or $53,000.  Since you will be self employed, you need to calculate your net earnings from self-employment which takes into account the eductible part of your self employment tax and contributions business makes to SEP.  Good read on SEPs at IRS site. and take a look at chapter 2 of Publication 560. I hope that helps and I recommend hiring a CPA in your area to help.
In addition to the normal limits, A Solo 401(k) allows you to contribute up to 20% of net profits (sole proprietor) or 50% of salary (if a corporation), up to $49,000. Note that the fees for 401(k) accounts are higher than with the IRA. See 401(k)s for small business. "It's not possible for them to be comingled. From the IRS FAQ: Does my employer need to establish a new account under its 401(k),   403(b) or governmental 457(b) plan to receive my designated Roth   contributions? Yes, your employer must establish a new separate account for each   participant making designated Roth contributions and must keep the   designated Roth contributions completely separate from your previous   and current traditional, pre-tax elective contributions. It doesn't have to be a separate ""account"" necessarily, but the amounts must be tracked separately as if they were in separate accounts: Does separate account refer to the actual funding vehicle or does it   refer to separate accounting within the plan's trust? Under IRC Section 402A, the separate account requirement can be   satisfied by any means by which an employer can separately and   accurately track a participant’s designated Roth contributions, along   with corresponding gains and losses." I would definitely recommend contributing to an IRA. You don't know for sure you'll get hired full-time and be eligible for the 401(k) with match, so you should save for retirement on your own. I would recommend Roth over Traditional IRA in your situation, because let's say you do get hired full-time. Since the company offers a retirement plan, your 2015 Traditional IRA contribution would no longer be deductible at your income level (assuming you're single), and non-deductible Traditional IRAs aren't a very good deal (see here and here). If there's a decent chance you would get hired, this factor would override the pre-tax versus post-tax debate for me. At your income level you could go either way on that anyway. A Solo 401(k) would be worth looking into if you wanted to increase your contribution limit beyond what IRAs offer, but given that it sounds like you're just starting out saving for retirement, and you may be eligible for a 401(k) soon, it's probably overkill at this point. They are mutually exclusive.  Provided you meet the income limits you can contribute to both.  Employer match do not count toward the 18K.   On the other hand traditional IRA and Roth IRA are inclusive.  So if single and making having a MAGI under 118K, you could do the 18K of your own money into a 401(k), and $5,500 into a Roth. You can put in $23,500 of your own money with the employer match on top of that. I routinely max out my 401k contributions.  The company's stupid website actually forces me to make two contributions -- one for the regular contribution, and another for the Catchup Contribution. I routinely adjust my 401k contribution throughout the year -- at the first of the year, I calculate how much to withhold such that I can adjust withholding to 6% of salary more than before, once I hit the SS tax limit.  At the first of the year, I ignore bonuses.  I re-adjust (if needed) once I know bonuses. I've worked for my company for almost 30 years now. "Before anything, I see that no one mentioned the one thing about 401(k) accounts that's just shy of magic - The matching deposit. In 2015, 42% of companies offered a dollar for dollar match on deposits. Can't beat that.  (Note - to respond to Xalorous' comment, the $18K OP deposits can be nearly any percent of his income. The typical match is 'up to' 6% of gross income. If that's the case, the 401(k) deposits are doubled. But say he makes $100K. The $18K deposit will see a $6K match. This adds a layer of complexity to the answer that I preferred to avoid, as I show with no match at all, and no change in tax brackets, the deferral alone shows value to the investor.) On to the main answer - Let's pull out a spreadsheet -  We start with $10,000, and assume the 25% bracket. This gives a choice of $10,000 in the 401(k) or $7500 in the taxable account. Next, let 20 years pass, with 10% return each year. The 401(k) sees the full 10% and after 20 years, $67K. The taxable account owner waits to get the 15% cap gain rate and adjusts portfolio, thus seeing an 8.5% return each year and carrying no ongoing gains. After 20 years of 8.5% returns, he has $38K net. The 401(k) owner on withdrawal pays the 25% tax and has $50K, still more than 25% more money that the taxable account. Because transactions within the account were all tax deferred.  EDIT - With respect to davmp's comment, I'll offer the other extreme -  In his comment, he (rightly) objected that I chose to trade every year, although I did assign the long term 15% cap gain rate, he felt the annual trade was my attempt to game the analysis. Above, I offer his extreme case, a 10% return each year, no trade, no dividend. Just a cap gain at the end. The 401(k) still wins. I also left the tax (on the 401(k)) at withdrawal at 25%, when in fact, much, if not all will be taxed at 15% or lower, which would put the net at $57K or 30% above the taxable account final withdrawal.  The next issue I'd bring up is that the 401(k) is taken out at the top (marginal) tax rate, e.g. a single filer with taxable income over $37,650 (in 2016) would save 25% on that 401(k) deduction. Of course if the deduction pulls you under that line, I'd go Roth or taxable. But, withdrawals start at zero. Today, a single retiree has a standard deduction ($4050) and exemption ($6300) for a total $10,350 ""zero bracket"" with the next $9275 taxed at 10%. This points to needing $500K in pre tax accounts before withdrawals each year would get you past the 10% bracket. (This comes from the suggestion of using 4% as an annual withdrawal rate).  Last - the tax discussion has 2 major points in time, deposit and withdrawal, of course. But, the answers here all ignore all the time in between.  In between, you see that for any number of reasons, you'll drop from the 25% bracket to 15% that year. That's the time to convert a bit of money to Roth and 'top off' the 15% bracket. It can happen due to job loss, marriage with new spouse either not working or having lower income, new baby, house purchase, etc.  Or in-between, a disability put you out of work. That permits you to take money out with no penalty, and little chance of paying even the 25% that you paid going in. This, from personal experience with a family member, funded a 401(k) with 28% money. Then divorced and disabled, able to take the $10K/yr to supplement worker's comp (non taxed) income." "The company itself doesn't benefit. In most cases, it's an expense as the match that many offer is going to cost the company some percent of salary.  As Mike said, it's part of the benefit package. Vacation, medical, dental, cafeteria plans (i.e. both flexible spending and dependent care accounts, not food), stock options, employee stock purchase plans, defined contribution or defined benefit pension, and the 401(k) or 403(b) for teachers. Each and all of these are what one should look at when looking at ""total compensation"". You allude to the lack of choices in the 401(k) compared to other accounts. Noted. And that lack of choice should be part of your decision process as to how you choose to invest for retirement. If the fess/selection is bad enough, you need to be vocal about it and request a change. Bad choices + no match, and maybe the account should be avoided, else just deposit to the match.  Note - Keith thanks for catching and fixing one typo, I just caught another." "This is a great question!  The IRS is not 100% clear on this. IRS publications do however very strongly suggest that assuming your wife has a plan providing family coverage, you can contribute up to your family maximum. If she does NOT have a family coverage plan then the answer is definitively no, you may only contribute the individual limit. Note if you have children covered by her plan then she is considered to have ""family coverage"" even if you are not covered by her plan (see here, question 12). From the 2012 IRS publication, bottom of Page 4. For 2012, if you have self-only HDHP coverage, you can contribute up to $3,100. If you have family HDHP coverage, you can contribute up to $6,250. This is presumably the referencing the definition which is introduced and discussed for married couples on Page 6: Rules for married people.   If either spouse has family HDHP coverage, both spouses are treated as having family HDHP coverage. If each spouse has family coverage under a separate plan, the contribution limit for 2012 is $6,250. You must reduce the limit on contributions, before taking into account any additional contributions, by the amount contributed to both spouse's Archer MSAs. After that reduction, the contribution limit is split equally between the spouses unless you agree on a different division. Example. For 2012, Mr. Auburn and his wife are both eligible individuals. They each have family coverage under separate HDHPs. Mr. Auburn is 58 years old and Mrs. Auburn is 53. Mr. and Mrs. Auburn can split the family contribution limit ($6,250) equally or they can agree on a different division. If they split it equally, Mr. Auburn can contribute $4,125 to an HSA (one-half the maximum contribution for family coverage ($3,125) + $1,000 additional contribution) and Mrs. Auburn can contribute $3,125 to an HSA. The last example is nearly the exact situation you are in assuming your wife's plan is family coverage. The only assumption beyond what is explicitly written you need to make is that you are considered to have family coverage in the example as per the ""Rules for married people"" section, even though your plan only is a single-coverage plan.  This conclusion seems to logically follow from information in the FAQs here (see Q32), as well as this document. Neither the above example nor any IRS documents referenced in this answer cover your situation completely."