Retirement Plans

Traditional IRA

Contributions may be tax-deductible now; you pay taxes when you withdraw in retirement.
Roth IRA

You contribute after-tax money; withdrawals in retirement are tax-free.
SEP IRA

For self-employed or small business owners; higher contribution limits, employer-funded.
SIMPLE IRA

For small businesses; allows employee contributions plus employer matching.
Solo 401(k)

For self-employed individuals with no employees; high contribution limits and flexible (can be Roth or traditional).

401(k)

Employer-sponsored, employee can contribute pre-tax or Roth;

employers may match.
Roth 401(k)

Like a 401(k) but contributions are after-tax;

withdrawals are tax-free.

403(b)

Like a 401(k) but for employees of public schools, nonprofits, and certain tax-exempt organizations;

allows pre-tax or Roth contributions, often with employer match.
SIMPLE 401(k)/IRA

For small businesses; allows employee contributions

with mandatory employer match.
SEP IRA

For small businesses/self-employed; only employer contributes,

high limits.