Free Online Calculators
Calculators for finance, health, math, and everyday use. Every calculator shows step-by-step work so you understand the math, not just the answer.
US Financial Calculators
- Mortgage Calculator — Amortization, PMI, taxes
- Paycheck Calculator — All 50 US states
- Income Tax Calculator — 2025 federal brackets
- Compound Interest Calculator — Multi-currency
- 401(k) Calculator — With employer match
- Loan Calculator — Any amortizing loan
- Auto Loan Calculator — Trade-in, sales tax
- Tip Calculator — Bill split per person
- Discount Calculator — Percent off, final price
- Sales Tax Calculator — All US states
- Profit Margin Calculator — Gross, operating, net
- ROI Calculator — Return on investment
- Break-Even Calculator — Units and revenue
UK Financial Calculators
- UK Tax Calculator — PAYE + National Insurance
- UK Mortgage Calculator — Repayment vs interest-only
- UK Salary Calculator — Gross to net take-home
- Stamp Duty Calculator — SDLT with first-time buyer relief
- VAT Calculator — All EU + UK rates
India Financial Calculators
- EMI Calculator — Home/car/personal loan EMI
- SIP Calculator — Mutual fund SIP returns
- India Income Tax Calculator — Old vs new regime
- GST Calculator — CGST + SGST / IGST
- PPF Calculator — 15-year lock-in
- FD Calculator — Quarterly compounding
- NPS Calculator — National Pension System
- EPF Calculator — Provident fund projection
Health & Fitness Calculators
- BMI Calculator — Metric and imperial
- Calorie Calculator — Mifflin-St Jeor
- BMR Calculator — Basal metabolic rate
- TDEE Calculator — Total daily energy expenditure
- Macro Calculator — Protein, carbs, fat targets
- Body Fat Calculator — US Navy method
- Ovulation Calculator — Fertile window estimate
- Sleep Calculator — Optimal sleep cycles
Math Calculators
- Percentage Calculator — 3 calculation types
- Fraction Calculator — Step-by-step work
- Standard Deviation — Population and sample
- Scientific Calculator — Expression-based, trig + log
- Triangle Calculator — Sides, angles, area
- Slope Calculator — Slope, y-intercept, distance
- Logarithm Calculator — log, ln, any base
Date & Time Calculators
- Age Calculator — Years, months, days, hours
- Date Calculator — Days between dates
- GPA Calculator — 4.0 scale
- Hours Calculator — Time between timestamps
- Working Days Calculator — Excludes weekends + holidays
- Random Number Generator — Range, count, no duplicates
Unit Converters
- Length Converter — cm, inches, feet, meters
- Weight Converter — kg, lbs, oz, grams
- Temperature Converter — Celsius, Fahrenheit, Kelvin
- Volume Converter — Liters, gallons, cups, ml
- Speed Converter — mph, km/h, m/s
Tech Calculators
- LLM API Cost Calculator — Compare GPT, Claude, Gemini pricing
- YouTube Earnings Calculator — Revenue by views and niche
- Meeting Cost Calculator — Real dollar cost with live timer
About These Calculators
Every calculator on this site shows the formulas and step-by-step calculations behind the result. That means you can check the work, learn the math, and verify the numbers — not just accept an answer. All calculators are free to use with no signup required.
Financial calculators use the latest tax rates and limits (updated annually). Health calculators cite established medical formulas with appropriate disclaimers. Math calculators show full working.