Each tool answers one question on its own, but they are most useful in sequence — first work out what you owe, then what to hold back, then whether the work is worth taking at all.
Start with what you owe
If you are paid on a 1099, no one is withholding anything for you. The 1099 and self-employment tax calculators estimate the two pieces that catch people out: self-employment tax, which covers Social Security and Medicare at 15.3% of net earnings with half of it deductible, and ordinary income tax on what is left after business expenses and the standard deduction.
Enter what you were actually paid and a realistic figure for expenses — mileage, phone, supplies, fees. The answer is an estimate, not a filed return, but it is close enough to plan against and far better than discovering the number in April.
Then decide what to hold back
The tax set-aside calculator turns that yearly estimate into a percentage to move out of every payment as it arrives. Holding back a fixed share of each deposit is the single habit that separates owners who are calm in April from owners who are not.
Most self-employed people land somewhere between 20% and 35% once state tax is counted. Put the money in a separate account, not a mental note, and treat the remaining balance as the only money you have.
Then test whether the work pays
The break-even calculator shows how much you must sell each month before anything is profit, once fixed costs are covered. The mileage reimbursement calculator converts business miles into a deduction at the IRS standard rate, which for a driver is usually the largest single deduction of the year.
The 1099 versus W-2 calculator compares a contract rate with a salary honestly, counting the employer half of payroll tax, unpaid time off, and benefits you would be buying yourself. A contract rate has to be meaningfully higher than a salary to come out even.
What the tools cannot do
They are educational estimates. They do not know your filing status edge cases, credits, prior-year losses, or state-specific rules, and nothing here is tax or legal advice. For a filed return, use the numbers as a starting point and check them with a preparer.
They also forget you the moment you close the tab. That is the honest reason to open an account: the same maths runs on your real entries, every day, without you re-typing anything.