Most people are familiar with the annual contribution limits to tax-deferred retirement plans. But many employers now offer an additional way to contribute to 401(k) and 403(b) plans that allows employees to save even more of their income for retirement. And I think this is a great opportunity.
Understanding tax-deferred 401(k), 403(b), and 457 plans
Tax-deferred retirement plans are offered by employers as a way for employees to elect to set aside a portion of their income for retirement. These contributions are tax-deferred meaning that you do not have to pay federal income tax on the contributions for the year that you contributed them to your 401(k), 403(b), or 457 plan. Instead, you pay federal income tax on the withdrawals in your retirement years.
A 401(k) plan is a tax-deferred retirement plan offered by for-profit companies. A 403(b) is a similar plan offered by non-profit companies or organizations. And a 457 is a similar plan offered by government institutions. They are all identical except that 401(k) and 403(b) plans are subject to an IRS penalty if you take withdrawals before age 59 1/2 whereas 457 plans do not have an early withdrawal penalty. A traditional IRA is similar but can consist of either tax-deferred contributions or post-tax contributions. When an IRA is created from only tax-deferred contributions (and no post-tax contributions), it is virtually identical in practice to a 401(k) or 403(b) plan.
Understanding Roth 401(k), 403(b), and 457 plans
In a Roth plan, you pay federal (and usually state) income tax on the contributions during the year that you made those contributions. In retirement, you pay no income tax on the withdrawals. Some employers will only offer tax-deferred 401(k), 403(b), or 457 plans but many will give the employee the option of either contributing to a tax-deferred 401(k), 403(b), or 457 plan or contributing to a Roth 401(k), 403(b), or 457 plan. Later in this post, I will discuss who should contribute to a tax-deferred plan and who should contribute to a Roth plan.
The 2026 contribution limits for 401(k), 403(b), and 457 plans
Each year, the federal government sets limits to the amount that an employee can contribute to a 401(k), 403(b), or 457 plan. That limit varies by the employee’s age. For 2026, contribution limits are:
- $24,500 for employees younger than age 50
- $32,500 for employees age 50 – 60 and older than age 63
- $35,750 for employees age 60 – 63
In addition, the IRS allows employers to contribute to 401(k) and 403(b) plans. These employer contributions are considered separate to the employee contributions and are often offered as “matching” contributions. Combined, the employee contributions plus employer contributions cannot exceed a total of $72,000. Not all employers will offer matching contributions and those that do often limit the amount that they will match to just a few thousand dollars. As a result, very few 401(k) or 403(b) plans reach the $72,000 total contribution limit.
The 403(b) & 401(k) after-tax with an after-tax Roth conversion option
In 2025, many companies and organizations began to offer employees the option of contributing more money into a 401(k) or 403(b) plan by using an after-tax with an after-tax Roth conversion. Here is how it works. First, the employee must make their age-determined maximum annual contribution to their 401(k) or 403(b) plan. So, for an employee younger than age 50, that would mean $24,500 in 2026. Next, the employee contributes post-tax income into a 401(k) or 403(b) plan and immediately converts that money into a Roth 401(k) or 403(b) plan. Importantly, the conversion must be done immediately, before those after-tax contributions have a chance to earn any money on investments in the regular 401(k) or 403(b) plan; otherwise, those earnings would be subject to additional income tax when converted to the Roth 401(k) or 403(b) plan.
The maximum amount that the employee can contribute to an after-tax with an after-tax Roth conversion 2026 is $47,500. For example John Smith is 40-years-old and works for State University. He makes his maximum contribution to his regular 403(b) of $24,500. He can then make an additional $47,500 after-tax contribution with an after-tax Roth conversion. His total contribution is $24,500 + $47,500 = $72,000. On the other hand, Jane Brown is 61-years-old and also works at State University. She makes her age-adjusted maximum contribution to her regular 403(b) of $35,750. She can then make an additional $47,500 after-tax contribution with an after-tax Roth conversion. Her total contribution is $35,750 + $47,500 = $83,250.
Tax-deferred 401(k) & 403(b) versus Roth 401(k) & 403(b): which is better?
If your employer gives you the option of either contributing to a regular tax-deferred 401(k)/403(b) plan or contributing to a Roth 401(k)/403(b) plan, you have to make a decision about whether it is better to pay income tax now or pay income tax in retirement. The guiding principle is to contribute to a Roth plan when your income tax rate is lower than it will be in retirement. Conversely, contribute to a tax-deferred plan when your income tax rate is higher than it will be in retirement.
A Roth 401(k) or 403(b) plan is better if:
- You are younger. It is better to pay income tax on 401(k) or 403(b) contributions when your federal income tax rate is lowest. For most people, this is early in their careers when their annual income is relatively low compared to where it will be later in life. Your financial goal should be to have enough retirement savings so that your taxable income (and thus income tax rate) is higher in your retirement years than it is in your earliest working years (when your taxable income is relatively low).
- You have a shortfall in income. Similarly, if your annual income is disrupted by being out of work for a few weeks or a few months, then your income that year will be relatively low and that will translate to having a relatively low federal income tax rate that year.
- You anticipate a big increase in income in the future. Let’s say you are an architect and have been working as an associate for the past 10 years. The firm typically promotes architects to partner status after 15 years. Partners make double the income as associates so it would be better to pay income taxes on your 401(k) contributions now, while your income (and consequently income tax rate) is low. There are many reasons why your income could rise in the future – maybe you anticipate a big promotion in the upcoming years, maybe you own your company and plan on selling in a few years, or maybe you are working part-time and planning on increasing to full-time in a few years. Any of these situations could result in you having a lower taxable income today than you will in your retirement years.
- You are planning a one-time big contribution to a charity this year. Maybe your congregation is planning on building a new church. Or maybe the Red Cross has an urgent appeal for donations due to a natural disaster. For whatever reason, if you anticipate making a very large contribution to charity in any given year, and if you itemize deductions on your federal income tax form, then that charitable contribution will lower your taxable income for that year. As a result, you are better off contributing to a Roth retirement account instead of a tax-deferred retirement account the year that your taxable income is low, making your income tax rate low.
- You believe that the federal government will raise income tax rates in the future. We are currently living in an era of historically low federal income tax rates. However, income tax rates are like a pendulum that swings back and forth every few years. Americans will complain about high income taxes and vote in politicians who cut income tax rates and reduce government services. A few years later, Americans realize that the government is no longer providing the services that Americans want and then vote in politicians who raise income taxes in order to expand services. What the income tax rates will be when you are retired is anyone’s guess but if you personally think that they will be higher in your retirement, then it is better to contribute to a Roth 401(k) or 403(b) while income tax rates are still low.
- You don’t think you will live very long. Maybe you smoke a pack of cigarettes a day, are obese, and are an anti-vaxxer. The bad news is that you probably will have a relatively short life expectancy in retirement. The good news is that you will be able to withdraw a lot of money from your retirement accounts each year in retirement because that retirement account does not need to last very long. That means that you could be in a higher income tax bracket in retirement than you were when you were working so contributing to a Roth retirement account would make sense.
- You plan on working into your 70’s. Similar to the person who does not think they will live very long, a person who does not plan on retiring until they are in their 70’s or 80’s will have fewer years that they will have to depend on the money from their retirement accounts and this means that they will likely have a relatively high income once they start taking the money out of those accounts. It is better to contribute to a Roth account when working and have a lower taxable income and thus a lower federal income tax rate. Also keep in mind that at age 73, the IRS mandates that you take required minimum distributions from your tax-deferred IRA, 401(k), 403(b), or 457 plan and this means that your taxable income could increase dramatically at age 73 if you also have regular income from working at that age. Roth accounts are not subject to required minimum distributions at age 73.
A tax-deferred 401(k) or 403(b) plan is better if:
- You are older. Most people have their highest earning years when they are older, generally in their 50’s. If this is the case, then you are better off making tax-deferred 401(k) or 403(b) contributions now and then taking money out of that tax-deferred 401(k) or 403(b) in retirement when you have a lower taxable income and thus a lower federal income tax rate. The additional benefit is that those tax-deferred contributions lower your taxable income in the year that you make those contributions and that means that you will have a lower effective income tax rate.
- You anticipate a fall in your annual income in the future. Maybe you think that artificial intelligence is going to eliminate your job. Or maybe you think that the factory that you work at will be going out of business. Or maybe you just want to cut back to working part-time once you reach age 55. You’re likely going to have a higher taxable income now than you will in retirement so you are better off making tax-deferred contributions today, before the anticipated fall in your annual income.
- You just inherited a tax-deferred IRA, 401(k), or 403(b). Usually, if you inherit a tax-deferred retirement account from a newly deceased relative, you are required to withdraw all of the money from those accounts within 5 years. Those withdrawals are considered taxable income on your federal income tax returns so they will make your total taxable income higher and thus put you in a higher federal income tax bracket with a higher effective income tax rate. You are better off contributing to your own tax-deferred 401(k) or 403(b) plan when you are taking the required distributions from the inherited tax-deferred retirement plan. This allows you to offset the increase in your taxable income from the inherited retirement account withdrawals with the decrease in your taxable income from the contributions to your own tax-deferred retirement account.
- You just inherited an annuity (maybe). Inherited annuities (and IRAs) can be complicated. They sometimes consist of both a taxable component and a non-taxable component. They are also usually subject to the requirement that all of the money be withdrawn within 5 years of inheriting them. If an annuity (or IRA) consist of both taxable and non-taxable components, then the annuity company will likely make you withdraw the taxable component first and then withdraw the non-taxable component later. So, if half of the annuity is taxable and half is not-taxable and you withdraw the annuity over 4 years, you’ll pay income taxes on the withdrawals during years 1 & 2 and you will not pay income taxes the withdrawals during years 3 & 4. Therefore, you are better off contributing to your own tax-deferred 401(k) or 403(b) during years 1 & 2 in order to lower your total taxable income (and thus income tax rate) during those years. Importantly, anytime you inherit an annuity or IRA, make sure that you ask the insurance company or financial institution holding that annuity or IRA about whether or not all of the withdrawals are taxable and if not, which years’ withdrawals will be taxable and which years’ withdrawals will be tax-free.
- You think you will live very long. The longer your life expectancy in retirement, the more years your retirement savings will have to last. That means that you will likely have a relatively lower taxable income every year in retirement. Lower annual income means a lower income tax rate. Therefore, you may be better off with a tax-deferred retirement account so that you pay income taxes when your income tax rate is lower than it was when you were working.
- You believe in a zombie apocalypse. If you think that the world is going to end about the time you turn 65 or if you think that world is going to turn to bitcoin and U.S. dollars will be worthless in the future, then why pay income taxes on Roth contributions during your working years. For that matter, why contribute to a retirement account at all? The problem is that if the zombie apocalypse never happens, then you’ll be living in a homeless shelter and eating cat food once you retire if you haven’t saved.
So who should contribute to a 403b & 401k after-tax with an after-tax Roth conversion?
Anyone who has enough income to contribute the maximum to their 401(k) or 403(b) plan ($24,500 in 2026 for those younger than age 50) should think about making additional after-tax contributions to a 401(k) or 403(b) with an after-tax Roth conversion. The reality is that contributing $24,500 to your retirement account every year is pretty darn good. Assuming an average annual return of 8%, working for 35 years, and then withdrawing 4% out of your retirement account every year, you would have an annual income in retirement of $196,000! But when you factor in inflation at 3% per year, that $196,000 is equal to only $69,000 in today’s dollars. If you add in the average Social Security benefit of $24,000 per person, this adds up an annual retirement income of $93,000 if you are single and $117,000 if you are married. If you are planning on doing a lot of traveling in retirement or maybe buying a second home or buying a boat in your retirement years, then $93,000 a year may not be enough.
Contributing to a 401(k) or 403(b) with an after-tax Roth conversion is always better than investing money in a regular brokerage account if you are investing for retirement. You will have to pay capital gains taxes on the earnings from those brokerage account investments whereas you won’t pay any taxes on the earnings in your Roth account. So, if you have the money to make additional retirement savings, contribute to a 401(k) or 403(b) with an after-tax Roth conversion.
Some organizations offer their employees both a 403(b) and a 457. An example would be a public university that is considered to be both a state government institution and a nonprofit institution. In this case, an employee can contribute the maximum to both the 403(b) and the 457 plans for a total of $49,000 in 2026. This would result in an annual retirement income of $138,000 in today’s dollars. Add in Social Security and that results in $162,000 if you are single and $186,000 in today’s dollars if you are married. This is a lot of money but if your taxable income is currently $350,000 a year when you are working, you will be looking at a drop in income in retirement.
For physicians, the picture gets more complicated. Most doctors are about 30-years-old when they finish a 3-year residency and about 33-years old if they do a fellowship after that. The AMA reports that 42% of physicians retire before age 65. So physicians often have fewer working years to contribute to retirement savings than other workers. Fewer years investing for retirement means fewer years for compound interest to work its magic on your investment. Factor in an average medical school loan debt of $220,000 and physicians often contribute relatively less of their income to retirement early in their careers and need to catch-up in their 40’s and 50’s. For these mid-career and late-career individuals, contributing to a 401(k) or 403(b) with an after-tax Roth conversion can make a lot of sense.
As a retired physician, I cannot overemphasize the importance of having a balanced retirement portfolio that consists of both tax-deferred retirement accounts and Roth accounts. This allows for strategic withdrawal from both types of accounts each year in order to avoid having to pay excessive income tax. That way, you can preferentially withdraw from your Roth accounts during years when you have a lot of expenses and need a lot of money (such as travel or purchasing a second home) in order to avoid having a high taxable income that year that would cause your effective income tax rate to be high. On the other hand, you can rely on just your tax-deferred accounts in years when you have fewer expenses and do not need to withdraw as much money.
Retirement plan contribution strategy
If your employer offers a match to your 401(k) or 403(b). Figure out a way to at least contribute enough to maximize the match. This is free money and you should never turn down free money. So, if your employer will match up to $3,000 to your 401(k), contribute at least $3,000 yourself so that you can get the full additional $3,000 from your employer.
If your employer offers only a tax deferred 401(k), 403(b), or 457. You don’t have a choice – you can only make tax-deferred contributions up to the maximum that the IRS permits for your age. But, you can still contribute to a Roth IRA. If your income is less than $150,000 filing single or less than $236,00 married filing jointly, then you can contribute directly to a Roth IRA. If your income is higher than this, you can contribute after tax money into a traditional IRA and then immediately convert it to a Roth IRA (the so-called “backdoor” Roth IRA). In 2026, the IRA contribution limits are $7,500 for those under age 50 and $8,600 for those older than age 50.
If your employer offers you the choice of either a tax-deferred or a Roth 401(k), 403(b), or 457. In this situation, you have to decide whether you are better off with the tax-deferred option or the Roth option. Which option is best for you may change for any given year. For example, the Roth option may be better early in your career when your taxable income is lower and then the tax-deferred option may be better later in your career when your taxable income is relatively higher.
If your employer offers a 401(k) or 403(b) after-tax with an after-tax Roth conversion. First, assuming you are younger than age 50, decide whether your initial $24,500 contribution should go to a regular tax-deferred 401(k)/403(b) plan or a Roth 401(k)/403(b) plan. Then determine how much of your post-tax income you can afford to contribute to an after-tax 401(k) or 403(b) plan with an after-tax Roth conversion. Keep in mind that the maximum after tax contribution with after-tax Roth conversion is $47,500 per year.
If your employer offers both a 403(b) and a 457. This is common for public university employees. It opens up more options but also adds a layer of complexity. First, decide whether your initial contributions should be to a tax-deferred or Roth 457 (if your employer gives you a choice). Second, maximize your contributions to the 457 plan since unlike the 403(b), the 457 withdrawals are not subject to early withdrawal penalties if you retire before age 59 1/2 and need to tap into your retirement account. Third, after maximizing your 457 contributions, contribute to the 403(b) up to the age-determined maximum. Fourth, if your employer allows post tax contributions with an after tax Roth conversion, contribute up to $47,500 in post tax 403(b) contributions with an after tax Roth 403(b) conversion. This strategy allows employees younger than age 50 to put away a total of $96,500 in their retirement accounts each year. This would result in a whopping annual retirement income of $750,000, equal to $270,000 in today’s dollars.
If you have contributed the maximum to your 401(k), 403(b), or 457 plan(s). For money that you know you will be investing for retirement, first contribute to a post tax traditional IRA and then do an immediate conversion to a Roth IRA (the backdoor Roth IRA). Avoid making post tax contributions to a traditional IRA and leaving it in that traditional IRA because you will have to pay regular income tax on the earnings when you take the money out in retirement. After contributing the maximum to a backdoor Roth IRA, invest any additional money into a regular brokerage account. You will have to pay capital gains taxes on these investments but your capital gains tax rate will usually be less than your regular income tax rate.
If you have a side hustle. Many employees have self employment income in addition to their income from their employer. Maybe you are a weekend artist and sell your paintings. Maybe you are a university professor but do some outside consulting in your spare time. Or maybe you play in a band on Friday and Saturday nights. You can contribute up to 20% of your self-employed income to an SEP (simplified employee pension) with a maximum annual contribution of $72,000. SEP contributions are tax-deferred so they will decrease the adjusted gross income from your self employment income. If you have income that is on your IRS schedule C form, then you can contribute to an SEP.
Americans do not save enough for retirement
A goal of financial planning is to ensure that you have enough to fund your desired lifestyle in retirement. For most of us, that means having at least as much disposable income each year in retirement as we have during our working years. Ideally, we should have a greater annual disposable income when we are retired so that we can do all the fun things we’ve dreamed of doing when we were working. We want to be able to travel, to take up new hobbies, to renovate our kitchens, to buy an RV – and all that takes money. It takes gold to make our golden years golden.
But an AARP survey found that 20% of Americans over age 50 have no retirement investment savings. These individuals will have to survive on Social Security alone in their retirement. A recent Gallup poll found that 55% of Americans do not believe that they will be financially comfortable in retirement. With the decline in the number of companies that offer traditional pensions, it is increasingly up to individuals to take responsibility for their own retirement savings. This means taking advantage of 401(k), 403(b), and 457 plans when available. The new option of after-tax contributions with after-tax Roth conversion that many employers are now offering for their 401(k) and 403(b) plans now makes it easier for Americans to save enough to fund their retirements.
December 15, 2025