Calculators

• Age Calculator | CrispToolkit
  Calculate age from birthdate.
• Date Difference — Tool | CrispToolkit
  Days between two dates.
• BMI Calculator | CrispToolkit
  Compute body mass index (BMI) 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 — Tool | CrispToolkit
  Future value with periodic compounding.
• Aspect Ratio — Tool | CrispToolkit
  Resize dimensions and simplify ratios.
• PPI / DPI — Tool | CrispToolkit
  Compute pixels per inch from pixel dimensions and diagonal size.
• Epoch ⇄ Date — Tool | CrispToolkit
  Convert Unix time to date and back.
• Temperature Converter
  Celsius, Fahrenheit, Kelvin.
• Base Converter | CrispToolkit
  Convert numbers between binary, octal, decimal and hexadecimal.
• Discount — Tool | CrispToolkit
  Compute savings and final price after discount.
• 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 — Tool | CrispToolkit
  Compound annual growth rate.
• ROI Calculator
  Return on investment.
• Running Pace/Time/Distance
  Solve any of the three.
• Roman Numerals
  Roman ↔ Integer.
• Circle — Tool | CrispToolkit
  Compute area and circumference from radius or diameter.
• Pythagorean Solver
  Find the missing side.
• Date Add/Subtract — Tool | CrispToolkit
  Add or subtract years, months, and days to a date.
• GCD / LCM — Tool | CrispToolkit
  Compute greatest common divisor and least common multiple.
• Salary ↔ Hourly
  Convert annual salary to hourly and back.
• Loan Amortization
  Payment, payoff time, and total interest.
• NPV
  Net present value of cash flows.
• Loan Payoff Time
  Months to pay off a loan with a given payment.
• IRR
  Internal rate of return.
• Rate Converter
  APR ↔ monthly rate (effective).
• Speed Converter
  mph ↔ km/h ↔ m/s.
• Break-Even Point — Tool | CrispToolkit
  Units and sales needed to cover fixed costs.
• Time Adder
  Add HH:MM:SS durations.
• Margin ↔ Markup
  Convert margin and markup; compute price.
• Percentage Of
  X% of Y.
• Fraction ↔ Decimal — Tool | CrispToolkit
  Convert between decimal and fraction, reduced to lowest terms.
• Rule of 72
  Doubling time estimate.
• Scientific Notation
  Decimal ↔ scientific (E) notation.
• Quadratic Solver
  Solve ax²+bx+c=0.
• Prime Factors
  Factorization & divisor count.
• Proportion Solver
  Solve a:b = c:x.
• Mean & Std Dev
  Population or sample standard deviation.
• Z‑Score
  Standardize a value given μ and σ.
• Day of Week
  Find weekday from date.
• Password Entropy
  Entropy & brute‑force time (client‑side).
• BMR & TDEE — Tool | CrispToolkit
  Mifflin‑St Jeor BMR and estimated daily calories by activity (TDEE).
• Body Fat (US Navy) — Tool | CrispToolkit
  Estimate body fat using the US Navy circumference method.
• Fuel Economy Converter | CrispToolkit
  Convert between mpg (US/Imp), L/100 km, and km/L.
• GPA (4.0 scale) — Tool | CrispToolkit
  Compute GPA from course credits and letter grades (unweighted).
• Cylinder: Surface & Volume — Tool | CrispToolkit
  Right circular cylinder formulas.
• Sphere
  Surface area and volume.