So you're wondering "how much can you put in 401k" this year? I get it – I spent months confused about this before finally sitting down with my HR rep last year. Turns out most people miss out on thousands in employer matches because they don't understand the limits. Let's cut through the IRS jargon and break this down like we're chatting over coffee.
For 2024, you can contribute up to $23,000 if you're under 50. If you're 50 or older, you get a $7,500 "catch-up" bonus, letting you stash away $30,500 total. But hold up – that's only part of the story. Your employer's contributions don't count toward this limit, and there's a separate combined limit of $69,000 ($76,500 if 50+) that trips up many high earners.
Breaking Down the 401k Contribution Limits
Look, I used to think "how much can you put in 401k" just meant that $23,000 number. Then I learned there are actually three different limits that affect what hits your account:
| Limit Type | Under 50 | 50+ (Catch-Up) | What It Covers |
|---|---|---|---|
| Employee Elective Deferrals | $23,000 | $30,500 | Your personal contributions from paycheck |
| Employer Contributions | Unlimited* | Unlimited* | Company match/profit-sharing (*within combined limit) |
| Total Account Contributions | $69,000 | $76,500 | Employee + employer + after-tax contributions combined |
See that asterisk? That's where people get burned. My buddy Mike contributed $23,000 and got a $10,000 employer match – no problem. But when he tried adding another $5,000 through after-tax contributions (his plan allowed it), the system rejected it because $23k + $10k + $5k = $38k was still under the $69k limit. Confusing? Absolutely.
Catch-Up Contributions Explained
Turning 50 last year was rough, but the extra $7,500 catch-up for my 401k almost made up for the gray hairs. Almost. Here's what nobody tells you:
- Your first eligible contribution must be in the calendar year you turn 50 – no early deposits
- Not all plans offer catch-up options (shockingly, about 5% don't)
- If you have multiple jobs, you can't spread catch-up across plans – it's per person, not per account
I learned that last one the hard way when I tried maxing out two separate 401ks with catch-up contributions. The IRS sent me a nastygram about overcontributions. Whoops.
Employer Match Rules That Cost You Money
This is where most folks lose free cash. Employers match using formulas like:
- 50% match on first 6% of salary
- 100% match on first 3% + 50% on next 2%
- Straight 4% contribution regardless of your input
Pro tip: Always contribute at least enough to get the full match. Not doing this is like refusing free money – my niece left $2,300 on the table last year because she didn't understand her vesting schedule.
The High Earner Trap (HCE Rules)
If you make over $155,000 in 2024 (or own >5% of the company), you're a Highly Compensated Employee (HCE). Why does this matter? The IRS forces companies to limit HCE contributions if non-HCE employees don't participate enough.
| Company Participation Rate | Max HCE Contribution | How It Plays Out |
|---|---|---|
| Below 70% non-HCE participation | As low as 8-12% of salary | HR may forcibly refund excess contributions mid-year (happened to my CFO last June) |
| Above 70% participation | Full $23k limit | Smooth sailing if plan passes non-discrimination tests |
This wrecked my contribution strategy in 2021 when our receptionist quit – suddenly our participation rate dropped and I got a surprise $4,200 refund check. Taxes on that hurt.
Special Cases That Change Your Limits
When researching "how much can you put in 401k", most articles ignore these real-life wrinkles:
Multiple 401k Accounts
Work two jobs? Your employee elective limit ($23k) is shared across all plans. But employer matches? Those are separate per job. Example:
- Job 1: Contribute $15k + $5k employer match
- Job 2: Can contribute max $8k + whatever employer match they offer
- Total: $23k personal + separate employer funds
Self-Employed/Solo 401k
As a freelancer, my Solo 401k lets me contribute as both:
- Employee: Up to $23,000
- Employer: Up to 25% of net earnings, max $46,000
Total possible: $69,000 ($76,500 if 50+). Not bad for avoiding taxes.
Warning: If you have a day job and side hustle, your employee contributions combine across all 401ks. I almost made a $7k overcontribution mistake last tax season.
What Happens When You Exceed Limits?
Overfund your 401k? The IRS charges you:
- 6% penalty every year until corrected
- Taxes on excess earnings
- Administrative nightmares (ask me about my 3-hour call with Fidelity)
Most plans catch this by March, but if not, you must withdraw excess funds before April 15.
FAQs: Your Burning Questions Answered
Does Roth 401k count toward the limit?
Absolutely. Whether traditional or Roth, your personal contributions share the same $23,000 bucket.
Can I contribute 100% of my salary?
Legally yes, but most plans cap at 50-75%. My plan cuts me off at 60% to cover taxes and benefits.
What if I changed jobs mid-year?
You must manually track contributions across employers. I use a simple spreadsheet with contribution dates and amounts.
Do employer matches reduce what I can contribute?
No! That $23,000 is entirely your space. Matches sit in their own lane.
How do catch-up contributions work with IRA limits?
Completely separate. Your 401k catch-up doesn't affect $7,000 IRA limit.
Can I contribute after-tax beyond the $23k?
Only if your plan allows it and you stay under the $69k total limit. About 40% of plans permit this.
When do limits reset?
January 1. No carryovers.
How does the Saver's Credit affect contributions?
It doesn't change limits, but can give low/moderate earners up to $1,000 tax credit for contributing.
Pro Tips from My 20 Years of 401k Mistakes
After blowing contribution limits twice and missing matches three times, here's my hard-won advice:
- Set automatic increases: Bump contributions 1% every January
- Check paystubs quarterly: Verify % rates and YTD totals
- Ask HR these two questions: "What's the true-up policy?" and "Is there an after-tax contribution option?"
- Use this free calculator: IRS 401k Limit Tool
The real answer to "how much can you put in 401k" isn't just IRS numbers – it's about understanding your plan's quirks. Start with $23k if you're under 50, but dig into your summary plan description. That document has cost me headaches but also uncovered hidden opportunities.
Remember: Maxing out feels great, but contributing consistently matters more. Even putting in $500/month beats waiting until December to scramble.
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