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Top 30 by traffic257M+/mo combined

Most popular calculators

The 30 calculators below are ranked by monthly Google search volume — the same numbers Ahrefs and Semrush see. Every one is free, runs entirely in your browser, and ships with a plain-English AI insight that turns the result into a decision.

Top three calculators

Math

Percentage Calculator

One calculator for all five classic percentage problems — X% of Y, X is what % of Y, X increased/decreased by Y%, and % change from one value to another. Full working shown.

25M+/monthOpen
Date & Time

Age Calculator

Enter your date of birth — we return your exact age in years, months, and days, plus total days lived, heartbeats, breaths, day of the week you were born, and days until your next birthday.

20M+/monthOpen
Finance

Currency Converter

Convert between 35 major world currencies using bundled mid-market rates from open.er-api.com. Cross-rate, inverse, and per-100/per-1000 reference values shown alongside the headline conversion.

15M+/monthOpen

Positions 4–30

Ranked by SV/mo
  1. 4BMI CalculatorCalculate your body mass index instantly in metric or imperial units. See your WHO category, healthy weight range, BMI Prime, and an AI insight for your result.15M+/month
  2. 5Loan EMI CalculatorCalculate your monthly EMI for any personal, auto, or home loan. See total interest, how much an extra payment saves, and if the deal is worth signing.10M+/month
  3. 6Tax CalculatorMulti-country tax owed estimator. Drop your gross salary, pick your country (and US filing status / India regime), see total tax + after-tax income with the bracket math broken down line by line.10M+/month
  4. 7Days Between Dates CalculatorDrop two dates — get the exact day count, business days (Mon-Fri only), weeks, months, years, and the calendar Y/M/D breakdown. Past or future, either order, includes leap years.10M+/month
  5. 8Unit ConverterSix measurement domains in one tool. Length (m/km/mi/ft/in), weight (kg/lb/oz/st), volume (l/gal/cup/oz), temperature (C/F/K/R), area (m²/ft²/acres/ha), and time (s/min/hr/day/wk/mo/yr).10M+/month
  6. 9Mortgage CalculatorCalculate your full monthly mortgage payment — principal, interest, property tax, insurance, and PMI. See if you clear the 28% affordability rule before you apply.8M+/month
  7. 10Days Until CalculatorDrop a target date — get the exact countdown in days, weeks, and Y/M/D from today. Past dates show days-since instead. Birthday, deadline, vacation, retirement — every counter from one tool.8M+/month
  8. 11Fraction CalculatorAdd, subtract, multiply, or divide two fractions. Result shown in simplest form, mixed-number form, and decimal — with the step-by-step working that produced it.8M+/month
  9. 12Calorie / TDEE CalculatorMifflin-St Jeor BMR, your Total Daily Energy Expenditure, and a complete macro split (protein · fat · carbs) for your weight-loss, maintenance, or muscle-gain goal.5M+/month
  10. 13Time Zone ConverterDrop a date, time, and source timezone — get the exact equivalent clock time in any other zone. Daylight saving transitions handled automatically via the IANA tzdata baked into your browser.5M+/month
  11. 14Word CounterPaste any text and get word count, character count (with and without spaces), sentence and paragraph counts, average word length, and accurate reading/speaking time estimates.5M+/month
  12. 15Pregnancy Due Date CalculatorDrop your last menstrual period (LMP) or conception date — get the estimated due date, current gestational age in weeks/days, trimester, and the full-term window. Cycle-length adjustment included.4M+/month
  13. 16Date Add / Subtract CalculatorAdd or subtract a duration (years + months + days) from any date. Calendar-aware month math handles edge cases like Jan 31 + 1 month = Feb 28 / 29 (clamped, not rolled to Mar 3).4M+/month
  14. 17GPA CalculatorCompute your semester or cumulative GPA across any number of courses. US 4.0 scale and Indian / Korean 4.5 scale supported. Each course weighted by its credit hours, with quality-points breakdown.4M+/month
  15. 18Discount CalculatorDrop the original price and discount percent — get the sale price, dollar savings, and effective price ratio. Reverse mode finds the discount % from original + sale prices.4M+/month
  16. 19Compound Interest CalculatorProject the final balance on a lump sum, a monthly contribution, or both. See the interest-vs-contribution split and find out how long until your money doubles.3M+/month
  17. 20Ovulation CalculatorPredict your most-likely ovulation date and the 6-day fertile window from the first day of your last period (LMP) and your cycle length. Sister calc to Pregnancy Due Date.3M+/month
  18. 21Countdown TimerDrop a target date and time — get a live countdown in days, hours, minutes, and seconds. Refresh the page or come back later for an updated count. Different from Days Until: this includes hours/minutes/seconds resolution.3M+/month
  19. 22Tip CalculatorRestaurant tip math, end-to-end. Drop the bill amount, pick the tip percent, optionally add tax and split across diners — get the per-person total in one tap.3M+/month
  20. 23VAT / Sales Tax CalculatorDrop a price and rate — get the tax-included total OR reverse from a tax-included total to the pre-tax price. 20+ country presets (UK 20%, EU avg, India GST 5/12/18/28%, AU/NZ GST, Japan, Singapore, UAE, US average) plus a custom-rate option.3M+/month
  21. 24Grade CalculatorTwo modes. (1) Given current grade + final exam weight + target overall, compute the score you NEED on the final. (2) Given current + final score + weight, compute your overall course grade and US letter.3M+/month
  22. 25Ratio CalculatorThree operations on ratios. Simplify any A:B to its simplest form. Find an equivalent value (A:B ↔ X:?). Or split a total in a given ratio. GCD-based simplification with full step-by-step working.3M+/month
  23. 26Retirement Savings CalculatorProject your retirement nest egg using future-value math with monthly compounding. Enter current age, target retirement age, present savings, annual contribution, and expected return — get the future value, the 4% safe-withdrawal income, and your FIRE number.2M+/month
  24. 27Budget CalculatorDrop your monthly take-home plus what you actually spend on needs / wants / savings — see how close you are to the 50/30/20 ideal and where to adjust.2M+/month
  25. 28Body Fat CalculatorThe most-validated tape-only body fat estimate. Drop your waist, neck, height, and (women) hip — get body fat percentage with category, accuracy band, and where you sit on the fitness range.2M+/month
  26. 29Water Intake CalculatorCompute your daily water target from bodyweight (35 ml/kg base), activity level, climate, and life-stage adjustments (pregnancy, breastfeeding). Output in liters, US cups, and 250 ml glasses.2M+/month
  27. 30Ideal Weight CalculatorFour classic ideal-body-weight formulas (Devine, Hamwi, Robinson, Miller) plus the BMI healthy-range method. None is 'the right answer' — together they give a healthy weight range, not a single target.2M+/month

Looking for something specific? Browse all 220 calculators across 15 categories, or read about how each one is built on the methodology page.