You can contribute to both a 401k and a Roth IRA at the same time. A 401k is an employer-sponsored plan. You can't own one individually. Anyone with income can have a Roth IRA. Combining both these types of accounts can allow you to maximize your retirement savings.oth a 401k and a Roth IRA have annual contribution limits. The contribution limit varies from year to year and is adjusted based on inflation. You can make the maximum contribution to both a 401k and a Roth IRA in the same year.