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Every calculator you'll ever need

163 calculators across payroll, finance, health, construction, and more. The only tool you need, free with no sign-up or paywalls.

Browse All Calculators
Free to use
Updated 2025-26
163 tools, 8 categories
Illinois Paycheck
Take-home pay after tax
A1C Calculator
Blood sugar to A1C
Square Footage
Area in sq ft instantly
Period Calculator
Next cycle prediction
Coast FIRE
Coast FIRE Calculator: When can you stop saving?
Find your financial independence number · Updated for 2025 limits
163
Free Calculators
50
US State Payroll Tools
8
Calculator Categories
2025–26
Tax Data Updated
0
Sign-ups Required

Browse by Category

Payroll & Tax
50+ calculators
State Paycheck Calculators
Self-Employment Tax
Federal Income Tax Rate
Time and a Half
Construction & Materials
21+ calculators
Square Footage
Concrete & Asphalt
Roof Pitch & Board Feet
Conduit Fill
Health & Fitness
24+ calculators
Period & Pregnancy
A1C & VO2 Max
Calorie & Macro
Body Fat & FFMI
Finance & Investment
20+ calculators
Mortgage & Refinance
Retirement / FIRE
Cap Rate & IRR
Debt Snowball
Education & GPA
16+ calculators
GPA Calculator
AP Score Calculators
ACT / SAT Score
Semester Grade
Math & Science
10+ calculators
Matrix & Determinant
Antiderivative
Correlation Coefficient
Interpolation
Food & Cooking
8+ calculators
Pizza Calculator
Turkey Cooking Time
Restaurant Calories
Recipe Conversion
Specialty & Other
15+ calculators
Age & Date Calculator
Blood Alcohol (BAC)
Bench Press Max
Pool Volume

Most Popular Right Now

All popular →
California Paycheck Calculator
Calculate your take-home pay after California state income tax and SDI for 2025-26.
High School GPA Calculator
Calculate your weighted or unweighted high school GPA by entering each course grade.
Debt Snowball Calculator
Build a step-by-step payoff plan using the debt snowball method with exact payoff dates.
FERS Retirement Calculator
Calculate your federal pension annuity benefit under the FERS retirement system.
SAT Score Calculator
Convert raw SAT section scores to scaled scores and estimate your total composite.
Reverse Mortgage Calculator
Estimate how much you can receive from a reverse mortgage based on your home equity.

What You Can Calculate

163 free tools across eight categories, each built for accuracy and updated for 2025-26.

Payroll and Tax

Individual paycheck calculators for all 50 US states apply the correct state income tax brackets, flat rates, FICA, and local taxes to produce an exact take-home estimate. Federal withholding follows IRS Publication 15-T tables updated for 2025-26. Calculators cover hourly and salary workers, single and married filers, with support for pre-tax deductions like 401(k) contributions and health insurance premiums.

Finance and Investment

Finance tools cover retirement planning with the Coast FIRE and FERS calculators, real estate analysis with cap rate and IRR calculators, and debt payoff with the debt snowball planner. The mortgage and refinance calculator compares monthly payments across loan terms. Each tool is built for personal finance decisions, not institutional models, so inputs match what a typical household actually knows.

Health and Fitness

Health calculators use published clinical formulas from the ADA, WHO, and CDC. The A1C calculator converts average blood glucose to estimated A1C and back. The period calculator predicts next cycle dates based on your cycle history. VO2 max uses the Rockport and Cooper protocol equations. Body fat, FFMI, and calorie calculators follow standard exercise science references, not proprietary black-box models.

Construction and Materials

Construction tools calculate material quantities for real projects. The square footage calculator handles complex room layouts with multiple shapes. The concrete bag calculator converts project dimensions to bag count by mix type. Asphalt, drywall, roofing, and flooring calculators output in the units contractors and homeowners actually use, including square yards, linear feet, and bag counts at standard coverage rates.

Education and GPA

GPA calculators support both weighted and unweighted high school scales and semester cumulative averaging. Standardized test calculators convert raw scores to scaled scores and percentiles for the SAT, ACT, LSAT, and AP exams using the official conversion tables published by College Board and LSAC. The semester grade calculator determines what you need on a final exam to hit a target course grade.

Math and Science

Math tools include the matrix determinant calculator for 2x2 through 5x5 matrices, the antiderivative calculator with step-by-step results, and the Pearson correlation coefficient calculator for datasets up to 30 pairs. The midpoint, acceleration, and mean-median-mode calculators are built for students and professionals who need a quick, reliable result without importing a full CAS system or statistical package.

Paycheck Calculators by State

All 50 US states, updated for 2025-26 tax rates. Select your state for an exact take-home pay breakdown.

IllinoisOhioMichiganWashingtonPennsylvaniaMarylandNew YorkVirginiaWisconsinArizonaMinnesotaNevadaNorth CarolinaOklahomaColoradoUtahGeorgiaFloridaTexasCaliforniaMassachusettsIowaKentuckySouth CarolinaTennesseeWashington DCIdahoArkansasKansasHawaiiNebraskaAlaskaConnecticutWest VirginiaMaineMississippiMontanaRhode IslandNew MexicoDelawareSouth DakotaVermontWyomingNew HampshireNorth Dakota+ All 50 States →

Why CalculatorFlux?

Built for accuracy, speed, and trust.

Instant Results
Every calculator runs client-side. No waiting, no server delays, results appear as you type.
Verified Accuracy
Payroll formulas sourced from IRS Publication 15-T. Health formulas from ADA, WHO, and CDC published guidelines.
Always Current
Tax rates, IRS limits, and medical formulas updated at the start of every tax year.
Private by Design
No account needed. Your numbers stay on your device. We do not log your calculations.

Articles & Guides

In-depth guides on finance, health, and more.

All articles →
75th Percentile Baby: What Above-Average Growth Means (2026)
Health & Fitness
July 16, 2026

75th Percentile Baby: What Above-Average Growth Means (2026)

75th percentile baby means heavier than 75% of same-age babies. Why this is normal, what stable trajectory means, and when doctors look closer.

11 min read
Read →
30th Percentile Baby: What Below-Average Growth Means (2026)
Health & Fitness
July 15, 2026

30th Percentile Baby: What Below-Average Growth Means (2026)

30th percentile baby means smaller than 70% of same-age babies. Why this is normal, what growth trajectory means, and when doctors actually intervene.

11 min read
Read →
Canadian Silver Coin Melt Value: Purity, Formula, and Table (2026)
Finance
July 14, 2026

Canadian Silver Coin Melt Value: Purity, Formula, and Table (2026)

Canadian silver coin melt value: 80% pre-1968 dimes, quarters, halves, 1967 transition, Silver Maple Leaf purity, formula, and reference table.

11 min read
Read →

Frequently Asked Questions

Common questions about CalculatorFlux and how our calculators work.

Yes, completely free. Every calculator on CalculatorFlux requires no account, no subscription, and no payment. We plan to keep all tools free forever.

Yes. CalculatorFlux has individual paycheck calculators for all 50 US states plus Washington DC. Each calculator applies the correct state income tax brackets, flat rates, and local taxes for 2025-26. States with no income tax, Texas, Florida, Nevada, Washington, Wyoming, South Dakota, Alaska, Tennessee, and New Hampshire, show federal-only take-home calculations.

Payroll calculators use the current IRS Publication 15-T federal withholding tables and each state's official published tax rates for 2025-26. Formulas follow IRS Publication 15-T and each state's official published tax tables, updated within two weeks of any IRS or state revenue department announcement. All results are estimates based on standard withholding, your actual paycheck may differ if your employer uses supplemental methods or if you have additional withholding elections.

No. Every calculator runs entirely in your browser. Your inputs never reach our servers. We do not log, store, or sell any calculation data.

All payroll and tax calculators are reviewed at the start of each tax year and updated within two weeks of any IRS publication or state revenue department announcement. Health and finance calculators use formulas from the ADA, WHO, CDC, and standard financial industry references, updated as guidelines change.

CalculatorFlux covers eight categories: Payroll & Tax (50+ state and federal tools), Finance & Investment (mortgage, FIRE, retirement, IRR), Health & Fitness (A1C, period, VO2 max, calorie), Construction & Materials (square footage, concrete, roofing), Education & GPA (high school GPA, SAT, LSAT, AP scores), Math & Science (matrix determinant, partial derivatives, statistics), Food & Cooking (pizza, turkey, recipe scaling), and Specialty (ERA, RVU, crosswind, zakat).