Trusty Calculator
English

Calculate with confidence

Fast, transparent calculators for construction, finance, math, education, business, and everyday decisions.

  1. Square Footage CalculatorConstructionFind the total area of one or more rectangles, triangles, or circles.
  2. Cubic Yard CalculatorConstructionConvert length, width, and depth into cubic yards or cubic meters.
  3. Percent Off CalculatorMathCalculate discount savings, price after discount, optional sales tax, and the final checkout total.
  4. Chronological Age CalculatorLifestyle & sportsCalculate exact chronological age in completed years, months, and days on a selected date.
  5. Credit Card Payoff CalculatorFinanceEstimate payoff time and interest for a fixed payment or a modeled percentage-or-floor minimum payment, with optional extra payments.
  6. Paint CalculatorConstructionEstimate paint from room walls and an optional ceiling, or from known area, with openings, coats, coverage, and waste.
  7. Pool Volume CalculatorConstructionEstimate pool water volume from plan dimensions, shape, shallow depth, and deep depth.
  8. Voltage Drop CalculatorElectricalEstimate conductor voltage drop and delivered voltage from current, length, material, and wire size.

Explore calculators

  1. 1Recessed Lighting CalculatorEstimate a centered recessed-light grid from maximum spacing or an early lumen-and-beam planning model.
  2. 2Parallel Resistor CalculatorCalculate equivalent resistance, total current, and total power for ideal resistors connected in parallel.
  3. 3Conduit Fill CalculatorCheck common 2023 NEC EMT fill from THHN/THWN-2 wire sizes and quantities, or enter custom listed areas.
  4. 4Pool Salt CalculatorCalculate how much pool salt to add from pool volume and the current and target salinity.
  5. 5Rafter CalculatorFind common-rafter geometry from either building span or horizontal run, pitch, overhang, and ridge thickness.
  6. 6Stair CalculatorFind a stair layout that fits the available run, including risers, treads, finished thickness, and stringer geometry.
  7. 7Chronological Age CalculatorCalculate exact chronological age in completed years, months, and days on a selected date.
  8. 8Steps to Miles CalculatorConvert step count to miles and kilometers using an entered average step length in inches.
  9. 9Bowling Score CalculatorScore a ten-pin bowling game frame by frame with strike, spare, and tenth-frame bonuses.
  10. 10CD Interest CalculatorUse this CD rate calculator to estimate interest and maturity value from a quoted APY or nominal rate.
  11. 11Credit Card Payoff CalculatorEstimate payoff time and interest for a fixed payment or a modeled percentage-or-floor minimum payment, with optional extra payments.
  12. 12Mortgage Recast CalculatorEstimate a new principal-and-interest payment after a lump-sum mortgage recast.
  13. 13Hours to Decimal CalculatorUse this time to decimal calculator to convert a duration or clock interval into decimal hours, minutes, and seconds.
  14. 14Markup CalculatorSolve cost, selling price, or markup percentage from the other two values and report profit and margin.
  15. 15CPM CalculatorSolve CPM, campaign cost, or impression count from any other two advertising-delivery values.
  16. 16Percent Off CalculatorCalculate discount savings, price after discount, optional sales tax, and the final checkout total.
  17. 17Proportion CalculatorSolve any one missing term in A divided by B equals C divided by D and show the completed proportion.
  18. 18Ratio CalculatorSimplify a multi-term ratio and scale every term from a selected position and target value.
  19. 19College GPA CalculatorCalculate term and projected cumulative college GPA from grade points, credits, and prior GPA.
  20. 20High School GPA CalculatorEstimate unweighted and weighted high-school GPA from grade points, credits, and course bonuses.
  21. 21Weighted Grade CalculatorNormalize completed weighted categories and find the score needed across the remaining course weight.
  22. 22Gold CalculatorEstimate net pure gold, melt value, and payout using any karat or fineness, entered price, currency, and payout rate.
  23. 23Scrap Gold CalculatorEstimate scrap-gold payout from matching gross weights, exclusions, karats, entered price, currency, payout, and fixed fee.
  24. 24Silver CalculatorEstimate net pure silver, melt value, and payout from percent or fineness, entered price, currency, and payout rate.
  25. 25Texas Paycheck CalculatorEstimate Texas take-home pay with 2026 IRS and state withholding methods, FICA, and supported payroll premiums.
  26. 26California Paycheck CalculatorEstimate California take-home pay with 2026 IRS and state withholding methods, FICA, and supported payroll premiums.
  27. 27Florida Paycheck CalculatorEstimate Florida take-home pay with 2026 IRS and state withholding methods, FICA, and supported payroll premiums.
  28. 28KG To LBS CalculatorValidated calculator with a stated method, worked example, and cited sources.
  29. 29Celsius To Fahrenheit CalculatorValidated calculator with a stated method, worked example, and cited sources.
  30. 30Cm To In CalculatorValidated calculator with a stated method, worked example, and cited sources.
  31. 31Days From Today CalculatorValidated calculator with a stated method, worked example, and cited sources.
  32. 32Days Until CalculatorValidated calculator with a stated method, worked example, and cited sources.
  33. 33Day Counter CalculatorValidated calculator with a stated method, worked example, and cited sources.
  34. 34Grams To Cups CalculatorValidated calculator with a stated method, worked example, and cited sources.
  35. 35ML To Grams CalculatorValidated calculator with a stated method, worked example, and cited sources.
  36. 36Grams To TBSP CalculatorValidated calculator with a stated method, worked example, and cited sources.
  37. 375k Pace CalculatorValidated calculator with a stated method, worked example, and cited sources.
  38. 38Bike Size CalculatorValidated calculator with a stated method, worked example, and cited sources.
  39. 39Whip Baseball CalculatorValidated calculator with a stated method, worked example, and cited sources.
  40. 40Letters To Numbers CalculatorValidated calculator with a stated method, worked example, and cited sources.
  41. 41Bag CalculatorValidated calculator with a stated method, worked example, and cited sources.
  42. 42Azimuth CalculatorValidated calculator with a stated method, worked example, and cited sources.
  43. 43Veterinarian-Entered Diphenhydramine Dose Calculator for DogsValidated calculator with a stated method, worked example, and cited sources.
  44. 44Bun Creatinine Ratio CalculatorValidated calculator with a stated method, worked example, and cited sources.
  45. 45Cat Age CalculatorValidated calculator with a stated method, worked example, and cited sources.
  46. 46Coulombs Law CalculatorValidated calculator with a stated method, worked example, and cited sources.
  47. 47Watt CalculatorValidated calculator with a stated method, worked example, and cited sources.
  48. 48Water Density CalculatorValidated calculator with a stated method, worked example, and cited sources.
Browse all 433 calculators

Calculations you can check

Formula

Every result shows its formula, assumptions, units, and primary sources.

Sources

Transparent calculators for practical decisions.

Last updated

Results update as you type.

Methodology