API Reference¶

The crate exposes a handful of functions and constants — enough to compute a 2025 federal take-home paycheck with no dependencies.

use us_paycheck_tax::{
    take_home, federal_income_tax, fica, standard_deduction, brackets,
    FilingStatus,
};

`take_home`¶

pub fn take_home(gross: f64, s: FilingStatus) -> (f64, f64, f64)

The headline function. Returns a tuple of (net, federal_income_tax, fica) for a given gross annual income and filing status.

net — take-home pay: gross − federal_income_tax − fica.
federal_income_tax — progressive tax on max(0, gross − standard_deduction).
fica — Social Security + Medicare (+ additional Medicare if applicable).

use us_paycheck_tax::{take_home, FilingStatus};

let (net, fed, fica) = take_home(75_000.0, FilingStatus::Single);
assert!((net - 61_148.50).abs() < 0.01);
assert!((fed - 8_114.00).abs() < 0.01);
assert!((fica - 5_737.50).abs() < 0.01);

`federal_income_tax`¶

pub fn federal_income_tax(taxable: f64, s: FilingStatus) -> f64

Progressive federal income tax on a taxable income (i.e. after the standard deduction has already been subtracted). Walks the brackets, taxing each slice at its own rate.

Returns 0.0 when taxable <= 0.0.
taxable is the post-deduction amount; call standard_deduction to subtract it first, or use take_home which does this for you.

use us_paycheck_tax::{federal_income_tax, standard_deduction, FilingStatus};

let gross = 75_000.0;
let taxable = gross - standard_deduction(FilingStatus::Single); // 60,000
let fed = federal_income_tax(taxable, FilingStatus::Single);
assert!((fed - 8_114.00).abs() < 0.01);

`fica`¶

pub fn fica(gross: f64, s: FilingStatus) -> f64

FICA payroll tax on a gross income:

Social Security — 6.2% of gross, capped at the wage base $176,100.
Medicare — 1.45% of gross (no cap).
Additional Medicare — 0.9% of gross above $200,000 (single) or $250,000 (married).

fica operates on gross (FICA is not reduced by the standard deduction), so pass the pre-deduction income.

use us_paycheck_tax::{fica, FilingStatus};

// High earner: SS capped, additional Medicare applies
let f = fica(350_000.0, FilingStatus::Single);
assert!((f - 17_343.20).abs() < 0.01);

`standard_deduction`¶

pub fn standard_deduction(s: FilingStatus) -> f64

The 2025 federal standard deduction for the filing status:

Filing status	Standard deduction
`Single`	`$15,000`
`Married`	`$30,000`

use us_paycheck_tax::{standard_deduction, FilingStatus};
assert_eq!(standard_deduction(FilingStatus::Single), 15_000.0);
assert_eq!(standard_deduction(FilingStatus::Married), 30_000.0);

`brackets`¶

pub fn brackets(s: FilingStatus) -> &'static [(f64, f64)]

The 2025 federal brackets as a slice of (ceiling, rate) pairs. The top bracket's ceiling is f64::INFINITY. Each pair means: income up to ceiling (and above the previous ceiling) is taxed at rate.

2025 brackets — Single¶

Taxable income over	up to	Rate
`$0`	`$11,925`	`10%`
`$11,925`	`$48,475`	`12%`
`$48,475`	`$103,350`	`22%`
`$103,350`	`$197,300`	`24%`
`$197,300`	`$250,525`	`32%`
`$250,525`	`$626,350`	`35%`
`$626,350`	`+∞`	`37%`

2025 brackets — Married filing jointly¶

Taxable income over	up to	Rate
`$0`	`$23,850`	`10%`
`$23,850`	`$96,950`	`12%`
`$96,950`	`$206,700`	`22%`
`$206,700`	`$394,600`	`24%`
`$394,600`	`$501,050`	`32%`
`$501,050`	`$751,600`	`35%`
`$751,600`	`+∞`	`37%`

use us_paycheck_tax::{brackets, FilingStatus};
let single = brackets(FilingStatus::Single);
assert_eq!(single[0], (11_925.0, 0.10));
assert!(single.last().unwrap().0.is_infinite()); // top bracket has no ceiling

`FilingStatus`¶

#[derive(Clone, Copy, PartialEq, Eq)]
pub enum FilingStatus { Single, Married }

Pick the bracket set and deduction. Married here means married filing jointly — the doubled brackets and doubled standard deduction.

Constants¶

All 2025 figures are exposed as pub const so you can reuse them directly:

Constant	Value	Meaning
`STD_DEDUCTION_SINGLE`	`15_000.0`	2025 standard deduction, single
`STD_DEDUCTION_MARRIED`	`30_000.0`	2025 standard deduction, married
`SS_RATE`	`0.062`	Social Security rate (6.2%)
`SS_WAGE_BASE`	`176_100.0`	2025 Social Security wage base cap
`MEDICARE_RATE`	`0.0145`	Medicare rate (1.45%)
`ADDL_MEDICARE_RATE`	`0.009`	Additional Medicare rate (0.9%)

Out of scope

This crate covers federal tax only. State and local income tax, pre-tax deductions (401(k), health premiums), and refundable credits are not modeled here. For the full state-by-state take-home picture, use the StateWage paycheck calculator{: target="_blank" rel="dofollow"}.

API Reference¶

take_home¶

federal_income_tax¶

fica¶

standard_deduction¶

brackets¶