Self-Employed? Here's Every Free Calculator You Need for Taxes and Retirement

Being self-employed changes your relationship with taxes and retirement savings in ways that catch a lot of people off guard the first year — there's no employer withholding anything automatically, and no employer-sponsored 401(k) waiting for you. Here's the practical set of calculators worth having on hand.

Self-employment tax: the one new employees never had to think about

As a W-2 employee, your employer pays half of your Social Security and Medicare tax automatically. As a self-employed person, you owe both halves yourself — this is self-employment tax, calculated separately from and in addition to regular income tax. It's the single most common surprise in a first year of self-employment, since nothing is withheld automatically to cover it.

Income tax, without a paycheck doing the math for you

Without employer withholding, estimating your total tax liability — federal, state, and self-employment tax combined — becomes something you have to actively do yourself, usually to figure out quarterly estimated payments rather than waiting until year-end.

Retirement savings without an employer plan

No employer 401(k) doesn't mean no retirement savings — it means the responsibility to start and fund one shifts entirely to you. Modeling out contributions, expected growth, and eventual Social Security benefit becomes worth doing deliberately, since there's no default employer plan quietly doing it in the background.

Getting paid, and invoicing for it

The practical side of self-employment: sending an invoice that actually gets paid, and issuing (or receiving) a W-9 to handle the tax-reporting side of a client relationship correctly.

None of this replaces an accountant once your situation has any real complexity — multiple income streams, business deductions, entity structure decisions. But for the first-pass numbers, these cover the calculations that catch most people off guard in year one.