Short answer: Log in to Fidelity NetBenefits, open your workplace plan, and look for the contribution amount option (often under a Quick Links menu next to the plan name). Enter the new percentage or dollar amount and confirm. Changes usually take effect from an upcoming paycheck. Some employers handle changes through payroll or HR instead, so if you do not see the option, your plan may not allow online changes. Changing what your contributions are invested in is a separate step.
How to Change Your 401(k) Contribution in NetBenefits
- Log in to NetBenefits using the official Fidelity site. Some employers have a custom NetBenefits address, so use the link your employer gave you.
- Open your workplace plan from the home page.
- Find the contribution option. Look for Contribution Amount under Quick Links, or similar wording. Menu names vary by plan.
- Enter your new percentage or dollar amount. If your plan offers both pre-tax and Roth, you may be able to split the contribution between them.
- Review and confirm. Save the confirmation for your records.
- Check your next pay stub to make sure the new amount is being deducted.
If your plan does not allow online changes, ask your HR or payroll team for a contribution form. Only use phone numbers from your own statement or fidelity.com, because search results for 401(k) topics are full of fake “support” numbers.
Change Investments: Future Contributions vs. Your Existing Balance
| What you want to change | What to look for in NetBenefits |
|---|---|
| Where new paycheck contributions go | Change Investments, then Change Investment Elections. Your percentages must total 100%. |
| How your current balance is invested | Exchange or rebalance options under Change Investments. Choose which sources and funds to move. |
These are separate. Changing your contribution rate does not change your investments, and changing investment elections does not move money you already hold. See our 401(k) fees guide before choosing funds.
How Much Should You Contribute?
- Start with the match. If your employer matches contributions, contribute at least enough to get the full match.
- Raise it with each pay increase. Many plans offer an automatic increase feature that raises your rate each year. You can usually turn it on or off.
- Know the 2026 limits. You can defer up to $24,500, plus an $8,000 catch-up at 50 or older ($11,250 at 60 to 63). See our contribution limits guide.
- Roth or pre-tax? Pre-tax lowers this year’s taxable income. Roth costs more now and is tax-free later. See our Roth contributions guide.
Per-Paycheck Cost of Common Contribution Rates
| Annual pay | 5% | 10% | 15% |
|---|---|---|---|
| $50,000 | $2,500 a year | $5,000 a year | $7,500 a year |
| $80,000 | $4,000 a year | $8,000 a year | $12,000 a year |
| $120,000 | $6,000 a year | $12,000 a year | $18,000 a year |
To see the amount per paycheck, divide by your number of pay periods (26 for every two weeks, 24 for twice a month, 12 for monthly). Contributing pre-tax lowers your take-home pay by less than the full amount, because you pay less income tax.
Watch Out for These Traps
- Front-loading. If you max out early in the year and your plan matches each paycheck, you may stop receiving the match for the rest of the year. Some plans make up the difference at year-end; many do not.
- Two jobs in one year. The $24,500 deferral limit is per person, so deferrals at both employers count toward the same limit.
- Timing. A change usually applies to future paychecks only, not ones already processed.
- Catch-up for higher earners. Starting in 2026, if your prior-year Social Security wages were over $150,000, catch-up contributions generally must be Roth.
Frequently Asked Questions
How long does it take for a 401(k) contribution change to take effect?
Usually from an upcoming paycheck, but timing depends on your employer’s payroll schedule. Check your next pay stub.
Can I change my 401(k) contribution at any time?
Most plans allow changes at any time, but some limit how often. Check your plan.
Why can’t I change my contribution online?
Some employers handle changes through payroll or HR systems instead of NetBenefits. Ask your benefits team.
Does changing my contribution change how it is invested?
No. Investment elections are a separate setting.
How do I stop my 401(k) contributions?
Set the contribution to 0% where your plan allows it. Consider the match you will give up first.
UseFidelity.com is an independent site and is not affiliated with Fidelity Investments. This article is general information, not tax, legal or investment advice. Figures last checked 3 November 2026.
Sources
- Employer NetBenefits guides for contribution and investment changes (menu names vary by plan)
- IRS Notice 2025-67 (2026 contribution limits)