🛠 Utilities & Tech Calculators
Seventeen tools for everything that does not fit a neat category: counting days, splitting a bill, sizing a concrete slab, working out a subnet mask or generating a password that is actually random.
Age Calculator
Exact age in years, months and days, leap years included.
📅Date Calculator
Days between dates, or add and subtract any period.
⏱Time Calculator
Add and subtract hours, minutes and seconds.
💼Work Hours Calculator
Weekly timesheet with breaks, overtime and gross pay.
🎓GPA Calculator
Semester and cumulative GPA on the 4.0 scale.
📝Grade Calculator
Your weighted grade and the final exam score you need.
🍽Tip Calculator
Tip, rounding and splitting the bill any way you like.
🏗Concrete Calculator
Cubic yards, cubic metres and bags for any pour.
🔄Conversion Calculator
Length, weight, volume, area, speed and temperature.
🌐Subnet Calculator
IPv4 CIDR, masks, host range and broadcast address.
🔒Password Generator
Strong random passwords generated in your browser.
🎲Random Number Generator
Secure random integers in any range, with or without repeats.
📐Square Footage Calculator
Room area, waste allowance and material cost.
😴Sleep Calculator
Bedtimes that land between sleep cycles, not inside one.
🏛Roman Numeral Converter
Numbers to numerals and back, 1 to 3,999.
⛽Fuel Cost Calculator
Trip cost from distance, economy and pump price.
🔢Number Base Converter
Binary, octal, decimal, hex and any base to 36.
About these 17 utilities & tech tools
The tools that do not fit anywhere else, and that is most of the useful ones: counting days to a deadline, totalling a week of shifts, splitting a restaurant bill, sizing a concrete pour, working out a subnet mask, generating a password that is genuinely random.
The password and random number generators use your browser's cryptographic generator, not Math.random, and nothing they produce leaves your device.