flat tax
One rate on all taxable income, with no brackets.
A single statutory rate applied to all taxable income, without graduation.
What that means in practice
A growing number of states work this way. Everyone pays the same percentage, which makes the arithmetic simple. Deductions and exemptions still apply though. So two people on the same income can still owe different amounts.
Flat structures eliminate bracket graduation but not progressivity entirely: standard deductions and exemptions preserve a rising effective rate across income. ⚠️ A state described as flat may still open with a zero-rate band, in which case the marginal and effective rates diverge exactly as they do under a graduated schedule.
Questions people ask
Who decides this — the federal government or my state?
Two governments, independently. The federal rule and your state's rule share a name and nothing else. So flat tax can mean one thing on your federal return and another on the state one.
Do I need to understand other terms before this one makes sense?
This one does not stand alone. Several related terms are linked below. flat tax is easier to hold once they are in place.
Is this the standard name for it?
It is. flat tax is the name this rule generally goes by. Searching it will find what you expect. That is not true of every tax term — some carry three names, depending on who is writing.
At which level of government is this determined?
Income tax concepts are defined independently at federal and state level. States may conform to the federal definition, conform selectively, or define their own; conformity is legislated and can be static (tied to a fixed date) or rolling. ⚠️ A federal change therefore propagates to some states automatically and to others only by subsequent state action.
What conceptual dependencies does this term carry?
This term has multiple conceptual dependencies, enumerated in the related-terms list. Definitions in tax law are frequently mutually referential — a provision's meaning depends on defined terms elsewhere in the code — so isolated reading commonly produces error.
Is this designation the settled one?
This designation is the settled term of art with limited alternative usage, so it maps reliably to statutory and agency references. Terms with multiple colloquial designations require more care when searching source material.