Loan Interest Calculator — Simple Interest

Two numbers describe your tax position and they are almost never the same. The marginal rate is the rate applied to your next dollar of income — it is the number that decides whether an extra shift, a bonus or a side contract is worth taking. The effective rate is total tax divided by total income, and it is always lower, because the early slices of your income were taxed at 10% and 12% no matter how much you went on to earn.

The practical consequence is that crossing into a higher bracket cannot reduce your take-home pay. A single filer who earns one dollar more than the 22% threshold pays 22 cents on that dollar and nothing changes underneath it. Advice built on the opposite belief — turning down a raise, refusing overtime near year end — costs real money.

Use the marginal rate when you value a deduction: a $1,000 deductible contribution is worth $220 to someone in the 22% band and $370 to someone at 37%. Use the effective rate when you compare years, budget for an annual bill, or judge whether a move across state lines actually improved your position.

Most people never calculate their own tax; their employer estimates it every payday from the Form W-4 on file. That estimate assumes the job in front of it is your only source of income and that your circumstances have not changed since you signed the form. Both assumptions break quietly.

The classic failure is a second income. Two jobs each withhold as though their salary were the whole picture, so both apply the standard deduction and both start you at the bottom of the bracket ladder. The combined return then lands with a balance due. The fix is the multiple-jobs step on the W-4, or a fixed extra amount withheld each period.

The mirror image is the large refund. It feels like a windfall, but it is money you lent the Treasury at zero interest for up to sixteen months. Reducing withholding so the return lands within a few hundred dollars of zero puts that cash in your own account, where it can sit in a savings product that actually pays.

Check withholding after any of the following: a raise, a bonus, a marriage or divorce, a new child, a house purchase, a change in dependants, the start or end of a second job, or a spouse returning to work.

A deduction lowers the income that gets taxed; a credit lowers the tax itself. That difference is enormous. A $2,000 deduction saves a 22% filer $440. A $2,000 credit saves them $2,000. Prioritise credits, and check refundability — a refundable credit pays out even when it takes your liability below zero.

On the deduction side, the decision is binary: take the standard deduction, or itemise. Itemising only wins when mortgage interest, state and local taxes up to the statutory cap, charitable gifts and qualifying medical costs together exceed the standard amount. Bunching two years of charitable giving into one calendar year is the usual way to make that arithmetic work.

Above-the-line reductions sit outside that choice and are available whether you itemise or not: traditional 401(k) and traditional IRA contributions, health savings account deposits, the deductible half of self-employment tax, and student loan interest within the income limits. These are the levers most households still have unused in December.

Federal rules are national. Everything below them is not. Nine states levy no broad tax on wage income; others run graduated schedules with top rates above 10%. But income tax is only the visible part. Property tax funds local services and varies by more than a factor of five between the cheapest and most expensive states. Combined sales tax adds up to double digits in some jurisdictions once local surcharges are counted, and it falls hardest on households that spend most of what they earn.

Insurance is the charge that has moved fastest. Home premiums have risen sharply in states exposed to wind, wildfire and hail, and in several markets the premium now rivals the property tax bill. A no-income-tax state with high property tax and high premiums can leave a middle income household worse off than a moderate income tax state next door.

That is why every calculator here has a version for all fifty states plus the District of Columbia, each carrying its own schedule, deduction, exemption and local charges. Pick your state below rather than reading a national average as though it were your answer.