Official references

Sources used by this tax estimate tool

We link to IRS pages so users can verify rules, payment instructions, forms, and current updates directly from the source.

IRS: Estimated Taxes IRS: Self-Employment Tax, Social Security and Medicare Taxes IRS: About Form 1040-ES IRS Topic 554: Self-Employment Tax IRS: About Publication 505, Tax Withholding and Estimated Tax SSA: Contribution and Benefit Base

Why the calculator uses editable assumptions

Tax limits, thresholds, due dates, and instructions can change. Editable assumptions let users keep the calculator useful while checking current IRS guidance.