A statutory rate is a percentage, dollar amount, or formula written directly into law by a legislature and applied uniformly to everyone the law covers. It gets its authority from a statute, meaning a formal law passed by a legislature and signed by the executive. That legislative origin is what sets it apart from a contractual rate two parties negotiate or a market rate that moves with supply and demand. A statutory rate reflects a policy decision, and it stays fixed until the legislature changes it or a formula built into the law recalculates it.
You run into these rates constantly without noticing. The 6.2% taken out of your paycheck for Social Security is one. So is the 1.5x overtime multiplier, the 21% federal corporate income tax, the 10% penalty on early retirement withdrawals, and the $7.25 federal minimum wage. Each of those numbers exists because Congress wrote it into law, not because a market or a contract produced it.
Floors, Ceilings, and Flat Rates
Statutory rates often work as either floors or ceilings. The federal minimum wage of $7.25 per hour is a floor: employers covered by the Fair Labor Standards Act can pay more, but not less. State usury laws are ceilings: lenders can charge less interest than the cap, but not more. If a lender exceeds the cap, consequences range from forfeiture of the excess interest to having the entire loan voided, depending on the state.
Other statutory rates are flat amounts that apply identically to every covered person or transaction. The 21% federal corporate income tax is one example, applied to all taxable corporate income whether the company earns $100,000 or $100 million.1GovInfo. 26 USC 11 – Tax Imposed The federal excise tax on gasoline is 18.3 cents per gallon, a fixed dollar amount per unit that does not move with gas prices.2U.S. Energy Information Administration. How Much Tax Do We Pay on a Gallon of Gasoline and Diesel Fuel?
Statutory Rates in Taxes You Pay
Most people encounter statutory rates first on a tax return or a pay stub.
Federal individual income tax uses a bracket structure. Different portions of your income are taxed at different rates, but the brackets and the rate inside each one are equally fixed by statute. State sales taxes work the same way at the state level: the legislature picks a percentage, and every covered transaction uses it.
Backup withholding is a statutory default rate the IRS falls back on when information is missing. If you fail to give a payer your Taxpayer Identification Number, the payer must withhold a flat 24% from reportable payments.3Internal Revenue Service. Topic No. 307, Backup Withholding That 24% is not a penalty. It is a pre-set tax rate designed to ensure some withholding happens even when the IRS does not yet know who to credit the payment to.
The federal estate and gift tax uses a top statutory rate of 40% on the portion of an estate or gift above the basic exclusion amount. For 2026, that exclusion is $15,000,000 per person.4Internal Revenue Service. What’s New – Estate and Gift Tax Congress can adjust the exclusion, but the 40% rate stays put until new legislation changes it.
Standard Mileage Rates
The IRS publishes standard mileage rates that taxpayers can use instead of tracking every vehicle expense. For 2026, those are 72.5 cents per mile for business, 20.5 cents per mile for medical and qualifying military moves, and 14 cents per mile for charitable driving.5Internal Revenue Service. IRS Sets Business Standard Mileage Rate at 72.5 Cents Per Mile, Up 2.5 Cents
Not all three are statutory rates in the strictest sense. The 14-cent charitable rate is written directly into the Internal Revenue Code and has not changed since 1998. The business and medical rates are recalculated each year by the IRS based on a study of actual operating costs. The statute grants the authority; the specific number changes annually.
Statutory Rates on Your Paycheck
Social Security tax is 6.2% of your wages, and your employer pays a matching 6.2%. For 2026, that rate applies to the first $184,500 you earn; wages above the ceiling are not subject to it.6Social Security Administration. Contribution and Benefit Base Medicare tax is 1.45% each for you and your employer, with no wage cap, plus an additional 0.9% on wages above $200,000 in a calendar year.7Internal Revenue Service. 2026 Publication 926 The 6.2% and 1.45% percentages have not moved in years, but the Social Security wage base rises annually under a statutory formula tied to average wage growth.
Employers also pay federal unemployment tax under FUTA at a statutory rate of 6.0% on the first $7,000 of each employee’s annual wages. In practice, employers in states with qualifying unemployment programs get a credit of up to 5.4%, dropping the effective rate to 0.6%.8Internal Revenue Service. Topic No. 759, Form 940, Employers Annual Federal Unemployment Tax Act (FUTA) Tax Return Both the 6.0% rate and the $7,000 wage base have gone unchanged for decades.
The federal minimum wage has been $7.25 per hour since 2009. Many states have set higher minimums; federal law is a floor, not a ceiling. For tipped employees, federal law allows a cash wage as low as $2.13 per hour, provided tips bring the total to at least $7.25.9U.S. Department of Labor. Fact Sheet #15: Tipped Employees Under the Fair Labor Standards Act (FLSA)
Overtime pay is one and one-half times the employee’s regular rate for every hour worked beyond 40 in a workweek.10U.S. Department of Labor. Overtime Pay The 1.5x multiplier is not an industry standard or a suggestion. It is a rate written into federal law, and it applies whether the extra hours fall on a weekday, weekend, or holiday.
Statutory Rates in Loans and Court Interest
Federal student loan interest is set by a statutory formula, not by Congress voting each year. The formula takes the yield on the 10-year Treasury note from the last auction before June 1 and adds a fixed percentage that varies by loan type. For undergraduate loans disbursed between July 2025 and June 2026, the add-on is 2.05 points, producing a rate of 6.39%. Graduate loans carry a 3.60-point add-on (7.94%), and PLUS loans carry a 4.60-point add-on (8.94%).11Federal Student Aid. Interest Rates and Fees for Federal Student Loans The law also caps each loan type: 8.25% for undergraduate, 9.50% for graduate, and 10.50% for PLUS loans.12Federal Student Aid Partners. Interest Rates for Direct Loans First Disbursed Between July 1, 2025 and June 30, 2026
When someone wins a money judgment in federal court, the losing party owes interest from the date of the judgment until they pay. The judge does not pick the rate. By statute, it equals the weekly average one-year constant maturity Treasury yield published by the Federal Reserve.13United States Courts. Post Judgment Interest Rate The number changes weekly, but the formula is locked into 28 U.S.C. § 1961. State courts often use a different approach, sometimes a flat statutory percentage.
Statutory Rates for Penalties and Damages
Statutory rates also set the price of noncompliance.
The IRS uses two separate late penalty rates. The failure-to-file penalty is 5% of the unpaid tax for each month a return is late, capped at 25%.14Internal Revenue Service. Failure to File Penalty The failure-to-pay penalty is much smaller: 0.5% of the unpaid tax per month, also capped at 25%.15Internal Revenue Service. Failure to Pay Penalty When both apply in the same month, the filing penalty is reduced by the payment penalty amount.
If you take money out of a 401(k), IRA, or similar retirement account before age 59½, you generally owe a 10% additional tax on the taxable portion of the distribution.16Internal Revenue Service. Substantially Equal Periodic Payments That 10% sits on top of the ordinary income tax on the withdrawal. Exceptions exist for certain hardships, but the default rate is non-negotiable.
Some federal laws let plaintiffs recover a fixed sum without proving exact financial harm. These are called statutory damages. Copyright infringement is the classic example: a copyright holder can choose statutory damages between $750 and $30,000 per work, or up to $150,000 per work if the infringement was willful.17Office of the Law Revision Counsel. 17 U.S. Code 504 – Remedies for Infringement: Damages and Profits Congress set the boundaries; the judge picks where within the range to land. The Fair Debt Collection Practices Act uses a smaller cap: up to $1,000 in additional damages per lawsuit against a debt collector who violates the statute, on top of any actual damages proved.18Office of the Law Revision Counsel. 15 USC 1692k – Civil Liability
Statutory Limits on Retirement Contributions
Congress uses statutory caps to limit how much you can shelter from taxes in retirement accounts each year. For 2026, the annual 401(k) contribution limit is $24,500. Workers 50 and older can add an $8,000 catch-up, and a higher $11,250 catch-up applies to workers aged 60 through 63 under the SECURE 2.0 Act.19Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
IRA contributions are capped at $7,500 for 2026, with a $1,100 catch-up for those 50 and older. Roth IRA eligibility also phases out at statutory income thresholds: for single filers, $153,000 to $168,000; for married couples filing jointly, $242,000 to $252,000.19Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500 These limits adjust each year by a statutory formula pegged to inflation, so Congress does not vote on them annually.
Set by Law Doesn’t Always Mean Frozen
Every statutory rate starts the same way: a bill passes through the legislature and becomes law. How the rate evolves after that depends on what the statute says.
Some rates are genuinely frozen. The 21% corporate income tax will stay at 21% until Congress passes a new law. The 14-cent charitable mileage rate has held since 1998 because it is hard-coded into the tax code. Changing either requires the full legislative process.
Other rates adjust automatically through indexing. Congress writes a formula into the statute, and an administrative body calculates the new number each year. The Social Security wage base rises with average wages. The 401(k) contribution limit rises with inflation. Federal student loan rates reset each July based on Treasury yields. No new legislation is needed; the formula runs on its own.
A third category sits between the two. The IRS business mileage rate is not written into the statute as a fixed number, and it is not pegged to a single index. The statute gives the IRS authority to set the rate based on an annual study of vehicle operating costs, leaving the agency discretion over methodology. Federal post-judgment interest works similarly: the formula is statutory, but the underlying Treasury yield is published weekly by the Federal Reserve.13United States Courts. Post Judgment Interest Rate
The practical point is that “set by law” does not always mean “never changes.” Many statutory rates are designed to change on a schedule within a framework the legislature controls. That is why the Social Security wage base and the 401(k) limit shift slightly every year even though nobody passed a new law about them.