Calculators

• Age Calculator
  Calculate age from birthdate.
• Date Difference
  Days between two dates.
• BMI Calculator
  Body Mass Index from height and weight.
• Tip Calculator
  Tip + split the bill.
• Percent Change
  Increase/decrease from A to B.
• Loan Payment
  Monthly payment for a loan.
• Compound Interest
  Future value with compounding.
• Aspect Ratio
  Resize & simplify ratios.
• PPI/DPI Calculator
  Pixels per inch from size and pixels.
• Epoch ↔ Date
  Convert Unix time and dates.
• Temperature Converter
  Celsius, Fahrenheit, Kelvin.
• Base Converter
  Bin/Oct/Dec/Hex converter.
• Discount Calculator
  Savings and final price.
• Sales Tax Calculator
  Add tax to price.
• VAT Reverse Calculator
  Extract VAT from total.
• Unit Price Calculator
  Price per unit.
• Simple Interest
  Interest without compounding.
• CAGR
  Compound annual growth rate.
• ROI Calculator
  Return on investment.
• Running Pace/Time/Distance
  Solve any of the three.
• Roman Numerals
  Roman ↔ Integer.
• Circle Calculator
  Area & circumference.
• Pythagorean Solver
  Find the missing side.
• Date Add/Subtract
  Add days, months, years.
• GCD / LCM
  Greatest common divisor & least common multiple.
• Salary ↔ Hourly
  Convert annual salary to hourly and back.
• Loan Payoff Time
  Months to pay off a loan with a given payment.
• Rate Converter
  APR ↔ monthly rate (effective).
• Speed Converter
  mph ↔ km/h ↔ m/s.
• Time Adder
  Add HH:MM:SS durations.
• Percentage Of
  X% of Y.
• Rule of 72
  Doubling time estimate.
• Prime Factors
  Factorization & divisor count.
• Proportion Solver
  Solve a:b = c:x.
• Day of Week
  Find weekday from date.
• Password Entropy
  Entropy & brute‑force time (client‑side).