We've built a collection of the best free online calculators that actually work, look great, and respect your privacy. No signups, no downloads, no tracking — just open and use.
💰 Financial Calculators
1. Mortgage Calculator
Calculate your monthly mortgage payment with property tax, insurance, and PMI. Compare 15-year vs 30-year terms. Try it free →
2. Paycheck Calculator
See your net take-home pay after federal tax, state tax, FICA, 401(k), and deductions. Try it free →
3. Compound Interest Calculator
See how your investments grow over time with compound interest and monthly contributions. Try it free →
4. Income Tax Calculator
Estimate your 2026 federal and state income taxes with bracket breakdowns. Try it free →
5. Retirement Calculator
Plan your retirement — see how much to save, when you can retire, and if you're on track. Try it free →
6. Credit Card Payoff Calculator
See how long to pay off credit card debt and how much interest you'll pay. Try it free →
7. Rent vs Buy Calculator
Should you rent or buy? Compare total costs over time. Try it free →
⚖️ Health & Fitness Calculators
8. BMI Calculator
Calculate your Body Mass Index and see your healthy weight range. Try it free →
9. Calorie Calculator
Find your daily calorie needs for weight loss, maintenance, or muscle gain. Includes macros. Try it free →
10. Body Fat Calculator
Estimate your body fat percentage using the Navy method. Try it free →
11. Ideal Weight Calculator
Find your ideal weight using 4 medical formulas. Try it free →
12. Pregnancy Due Date Calculator
Calculate your estimated due date and see which trimester you're in. Try it free →
📐 Math & Science Calculators
13. Percentage Calculator
Calculate percentages, percentage change, and "X is what percent of Y." Try it free →
14. Fraction Calculator
Add, subtract, multiply, and divide fractions with simplified results. Try it free →
15. GPA Calculator
Calculate your cumulative GPA from individual course grades. Try it free →
🔧 Everyday Tools
16. Tip Calculator
Calculate tips and split bills instantly. Try it free →
17. Age Calculator
Find your exact age in years, months, days, hours, and minutes. Try it free →
18. Gas Mileage Calculator
Calculate MPG and fuel costs for any trip. Try it free →
19. Electricity Cost Calculator
See how much any appliance costs to run per day, month, and year. Try it free →
20. Discount Calculator
Calculate sale prices with tax. Try it free →
Why These Calculators?
- 100% free — no signups, no paywalls
- Privacy-first — all calculations run in your browser, nothing sent to servers
- Works offline — save any page and use without internet
- Mobile-friendly — responsive design works on any device
- No ads blocking content — clean, usable interface