Do I have to fund a SEP-IRA for my employees too?

Yes, and this is the SEP-IRA's biggest catch. A SEP requires you to contribute the same percentage of pay for every eligible employee that you contribute for yourself. So if you put 20% of your own compensation into the plan, each eligible worker gets 20% of theirs. Eligibility generally covers anyone 21 or older who has worked for you in three of the last five years and earned above a small IRS threshold. You cannot contribute more for yourself and less for staff. If you have employees and want to save aggressively just for yourself, a Solo 401(k) won't work either once you have non-spouse staff; a Safe Harbor 401(k) or SIMPLE IRA may fit better. Confirm current rules at irs.gov.