Best 401(k) Providers for Small Business 2026
Guideline, Human Interest, ShareBuilder 401k, and Ubiquity compared on actual pricing, fund options, and admin burden for teams under 100 people.
Is it right for you?
- Calculate total annual cost: base fee + per-participant fee vs a flat-fee provider
- Confirm the provider integrates with your payroll software before signing
- Verify they handle ERISA compliance, Form 5500 filing, and annual nondiscrimination testing
- Check that fund expense ratios average under 0.10% for index options
- Ask about Safe Harbor plan structure if you want to avoid discrimination testing
Quick verdict
Guideline is the best default 401(k) for Gusto or Rippling users. Human Interest is better for non-Gusto payroll integrations and a wider fund menu. ShareBuilder 401(k) is cheapest for very small teams. Ubiquity offers flat-fee pricing that gets competitive above 20 participants.
What small business 401(k) actually costs
Most 401(k) providers charge a base monthly fee plus a per-participant monthly fee. At 10 participants, the difference between providers can be $100 or more per month. At 50 participants, the gap can reach $500 per month.
Representative pricing for a 15-person team: Guideline at $49/month base + $8/participant = $169/month. ShareBuilder 401(k) at $25/month base + $8/participant = $145/month. Ubiquity flat fee at $80 to $95/month regardless of participant count. Human Interest at $120+ base plus per-participant, varying by plan tier.
Guideline: best for Gusto and Rippling users
Guideline integrates natively with Gusto and Rippling. Employee contribution elections flow automatically, employer matches calculate against each payroll run, and W-2 Box 12 reporting is handled without manual entry. This payroll sync is the main reason Guideline dominates the Gusto market.
Fund menu uses low-cost Vanguard and Fidelity index funds averaging 0.06% expense ratio. Annual nondiscrimination testing, Form 5500 preparation, and ERISA compliance are included. Guideline does not offer self-directed brokerage windows, the fund menu is curated index funds only, which works well for most employees but may not satisfy finance-savvy staff who want individual securities.
Safe Harbor plans: the simplest way to avoid discrimination testing
Standard 401(k) plans require annual nondiscrimination testing to ensure highly compensated employees (earning over $155,000 in 2026) are not contributing disproportionately. If the test fails, the IRS requires refunding excess contributions, a tax headache for founders.
A Safe Harbor 401(k) avoids this by requiring employer contributions for all eligible employees. The most common structure: a 3 percent non-elective contribution for all eligible employees, or a 100 percent match on the first 3 percent plus a 50 percent match on the next 2 percent of compensation. All major small-business 401(k) providers support Safe Harbor designs, and for companies with even a few high earners, the employer contribution cost often beats the annual refund headache.
Frequently asked questions
How much does Guideline actually cost per month? Guideline's Starter plan runs $39/month base plus $4 per active participant; the Core plan is $89/month base plus $8 per participant. For a 15-person team on Starter, that is about $99/month before the 0.15-0.35 percent annual account fee charged to participant balances.
What happens to 401(k) fees when an employee leaves? Most providers, including Guideline, charge a separate monthly base fee for former employees who still have a balance in the plan. Guideline's is $6/month per former employee, starting after a 90-day grace period, so cleaning up old accounts (via rollover) keeps costs down.
Is Human Interest more expensive than Guideline? Generally yes for small teams. Human Interest's Complete plan is about $180/month plus $7/employee/month, well above Guideline's Starter tier, though Human Interest offers a wider non-Vanguard/Fidelity fund menu and works with more non-Gusto payroll systems.
Do all small business 401(k) providers charge setup fees? Not always, and even when listed, they are often negotiable or waived. Human Interest lists a $499 installation fee but frequently waives it as part of ongoing promotions, so it is worth asking directly before assuming it applies to you.
What is a Safe Harbor 401(k) and do I need one? A Safe Harbor plan requires employer contributions for all eligible employees (commonly a 3 percent non-elective contribution or a matching formula) in exchange for skipping the annual nondiscrimination test. If you have even a few employees earning above the IRS highly-compensated threshold, Safe Harbor usually costs less than the risk of a failed test and refunded contributions.