One page per problem. No sign-up, no clutter.
Small, fast tools for the calculations and busywork that come up during a normal office day. Pick a tool below.
Triangle Angle Calculator
Enter two known angles of a triangle to find the third, plus whether it's acute, right, obtuse, and its side type.
→ open tool 03Polygon Calculator
Choose the number of sides and enter a diameter, measured across corners or across flats, to get side length, perimeter, and area.
→ open tool 04Cylinder Calculator
Enter a diameter and height to get radius, circumference, base area, lateral area, total surface area, and volume.
→ open tool 05Cone Calculator
Enter a base diameter and height to get slant height, base area, lateral area, total surface area, and volume.
→ open tool 16Area Calculator
Rectangle, square, circle, triangle, trapezoid, and parallelogram — all on one page, each updating as you type.
→ open toolLength Converter
Enter a value in any length unit — cm, inches, feet, and more — and see it converted to all of them at once.
→ open tool 17Temperature Converter
Enter a temperature in Celsius, Fahrenheit, or Kelvin and see it converted to all three at once.
→ open toolIdeal Height & Weight Calculator
Enter a height to see a general healthy-weight range and a Devine formula estimate, in metric or imperial units.
→ open tool 07Running Calculator
Solve for pace, time, or distance from the other two, and predict race times for 5K, 10K, half and full marathon.
→ open toolVoltage, Current & Resistance Calculator
Edit any two of voltage, current, resistance, or power — the other two solve automatically.
→ open tool 19Series & Parallel Resistance
Add as many resistors as you need and get the total resistance in series or parallel.
→ open tool 20Series & Parallel Inductance
Add as many inductors as you need and get the total inductance in series or parallel.
→ open tool 21Series & Parallel Voltage
Combine batteries or sources — series adds the voltages, parallel checks they match and keeps that voltage.
→ open tool 22Standard Resistor Values
Browse the IEC 60063 E6–E96 preferred value tables, scaled across the common decades.
→ open tool 23LED Series Resistor Calculator
Find the current-limiting resistor for one LED or a series string, plus the nearest standard value and power rating.
→ open tool 30RC Gear Ratio & Reference
Convert motor torque and RPM through a pinion/spur gear ratio, plus reference tables for typical RC gear ratios and radio systems.
→ open toolFull Moon Calculator
Today's moon phase, plus when the next full moon and new moon happen.
→ open tool 14ISS Tracker
Live position of the International Space Station — latitude, longitude, altitude, and speed, plotted on a map.
→ open tool 15Sunrise & Sunset Tracker
Uses your location to show today's sunrise, sunset, day length, and golden hour windows.
→ open toolRandom Number Generator
Set a range and how many numbers you need, with or without repeats — good for picking a winner or sampling a batch.
→ open tool 11Random Picker
Type in a list of options — like where to eat — and let it pick one for the group.
→ open tool 24FLAMES Calculator
Enter two names to find out: Friends, Lovers, Affection, Marriage, Enemies, or Siblings.
→ open toolAge Calculator
Enter a date of birth to get an exact age breakdown, plus total days, weeks, and hours lived.
→ open tool 26Age Gap Calculator
Enter two birth dates to see the exact age difference between two people.
→ open tool 27Birthday Calculator
See the countdown to your next birthday, what day it falls on, and upcoming milestone birthdays.
→ open tool