The coverage difference is about designation and breadth
A Self Plus One enrollment covers the enrollee and one eligible family member selected by the enrollee. A Self and Family enrollment covers the enrollee and every eligible family member; OPM says eligible family members are automatically covered even when they were not listed on the election form, subject to the program's eligibility rules.
A household with more than one eligible family member can elect Self Plus One, but only the designated person receives FEHB coverage under that enrollment. That can create a consequential gap for another eligible spouse or child. Self and Family is broader and can automatically cover a newly eligible family member from the applicable date, but it may not be necessary for every two-person household.
| Question | Self Plus One | Self and Family |
|---|---|---|
| Who is covered? | Enrollee plus one designated eligible member | Enrollee plus all eligible family members |
| Can a two-person household elect it? | Yes | Yes |
| Are other eligible members automatically covered? | No | Yes, under OPM eligibility rules |
| Is it always cheaper? | No | No |
Why Self Plus One can cost more
The government contribution and carrier pricing are calculated by enrollment type. OPM explicitly publishes a list of plan options where the enrollee share for Self Plus One exceeds the Self and Family share. The label therefore cannot be used as a proxy for price.
Compare both rates inside the same plan option. Switching plans just to compare enrollment types mixes two decisions: carrier and benefit design on one side, family tier on the other. Hold the plan option constant first, then compare whether another plan is a better overall fit.
- Confirm that the one person you plan to designate is an eligible family member under OPM rules.
- Compare exact employee-share rates, not program-wide averages.
- Check whether a court order or anticipated family change affects the needed coverage breadth.
- Review provider networks and prescriptions for every person who would be covered.
Plan for the next family change, not only today's headcount
Marriage, divorce, birth, adoption, a child's loss of eligibility, or another qualifying life event may create a time-limited opportunity to change enrollment. OPM generally requires a change outside Open Season to be consistent with the event, and the filing window varies by event.
If both spouses can enroll in FEHB, compare one family enrollment with other permitted arrangements, including separate Self Only enrollments where applicable. Dual FEHB enrollment is generally prohibited, so do not assume the same person can remain covered under two FEHB enrollments.
Questions about this FEHB decision
Can I choose Self and Family if I only cover one family member?
Yes. OPM says an enrollee who wishes to cover one eligible family member may elect either Self Plus One or Self and Family.
Is Self Plus One always less expensive than Self and Family?
No. OPM specifically identifies plan options where the Self Plus One enrollee share is higher. Compare the exact rates for both enrollment types in the same option.
Does Self Plus One cover two family members without the enrollee?
No. It covers the enrollee and one designated eligible family member.
Can I change from Self and Family to Self Plus One anytime?
Employees participating in premium conversion generally make that decrease during Open Season or within the applicable period after a consistent qualifying life event. Ask the employing office to confirm the permitted change and deadline.
Primary sources
Reviewed August 25, 2026. Each source below is an official federal page used for the claims on this resource.
- OPM FEHB enrollment handbook (opens in a new tab)
Definitions, designation rules, dual-enrollment limits, and opportunities to change coverage.
- OPM 2026 FEHB premiums (opens in a new tab)
Official warning and chart for Self Plus One premiums that exceed Self and Family.
- OPM FEHB eligibility (opens in a new tab)
Official categories and documentation rules for eligible family members.
This is general educational information, not legal, tax, financial, medical, or enrollment advice. OPM, your employing office or retirement system, the carrier brochure, Medicare, and the plan administrator control your actual eligibility, timing, costs, and coverage.