How our calculators work

Every Utilix tool page shows its own step-by-step breakdown and formula. This page covers the reference data behind them — where tax brackets and rates come from, how often we refresh them, and the rounding rules that apply across the site. See About for who maintains this.

US federal income tax — Salary Tax Calculator

2026 tax-year brackets (10/12/22/24/32/35/37%) and standard deductions ($16,100 single, $32,200 married filing jointly, $24,150 head of household) are taken from IRS Revenue Procedure 2025-32, published October 9, 2025. FICA uses the 2026 Social Security wage base of $184,500 (SSA “2026 Social Security Changes” fact sheet) at 6.2%, plus 1.45% Medicare on all wages. State income tax, AMT, and NIIT are not modeled — see the tool's FAQ.

India income tax — India Income Tax Calculator

Slab rates, standard deduction (₹75,000 new regime / ₹50,000 old regime), and the Section 87A rebate come from the Union Budget 2025 slab structure, which the Union Budget 2026 left unchanged for FY 2026–27. A 4% Health & Education Cess is added on top of slab tax. Surcharge for high earners (above ₹50 lakh) and old-regime deductions (80C, HRA, home loan interest) are not modeled — verify current figures at incometax.gov.in.

Pakistan income tax — Pakistan Income Tax Calculator

Slab boundaries and rates follow the salaried-individual tables published under each year's Finance Act (typically enacted June–August). Rates change annually — verify the current tax year at fbr.gov.pk.

Currency conversion

Live exchange rates are fetched from the Frankfurter API, which republishes European Central Bank reference rates. ECB rates update once per business day; they are mid-market reference rates, not the rate a bank or card network will actually give you on a transaction.

Health calculators (BMR / TDEE)

Basal metabolic rate uses the Mifflin-St Jeor equation, generally considered more accurate than the older Harris-Benedict formula for most adults. Activity multipliers for TDEE follow the standard sedentary-to-extra-active scale used in sports nutrition references. These are population-level estimates, not a substitute for a metabolic test or clinical guidance.

SAT ↔ ACT conversion

Score concordance uses the official 2018 College Board / ACT concordance study, the most recent joint table published by both testing organizations at the time of writing.

Rounding and display rules

Currency results round to the precision shown on each tool (typically 2 decimal places for USD-scale amounts, whole units for larger INR/PKR amounts). Percentages round to 1–2 decimal places depending on the tool. Indian and Pakistani rupee amounts use lakh/crore digit grouping (e.g. ₹1,00,000) rather than thousands grouping, matching local convention.

Update cadence

Tax-year tools are reviewed at least annually and sooner when a government publishes new figures — each tool page shows its own “last updated” date. If you find a figure that's out of date or wrong, let us know.

Disclaimer

All figures above are illustrative and provided for estimation and educational purposes. They are not tax, financial, legal, or medical advice. Always verify against the official source cited for your situation before filing, borrowing, or making a financial decision.