How to Pick the Right Calculator
Dates and times — the age calculator
works out an exact age in years, months, and days; the
date calculator adds and subtracts days and
counts the days between two dates, backed by the
day counter and
day of the week calculator.
For clocks rather than calendars, use the
time calculator,
hours calculator, and
time card calculator for shifts and
timesheets, and the time zone calculator
when the two ends of a call are in different places.
Building and housing — estimate materials before you buy: the
concrete calculator for slabs, footings,
and columns, square footage for
rooms and plots, and dedicated tools for
tile,
roofing,
mulch, and
gravel, with the
stair calculator for rises, runs, and stringers.
Measurements and units — the
conversion calculator is the general
workhorse; alongside it sit focused tools for
height,
mass,
weight,
speed, and
density, chemistry helpers for
molarity and
molecular weight, and the
Roman numeral converter.
Electronics — work circuits with
Ohm's law,
voltage drop,
resistor, and
electricity calculators.
Internet — plan networks with the
IP subnet calculator, generate strong
passwords with the password generator,
and convert data rates with the
bandwidth calculator; the
Base64 and
URL encode / decode tools handle
text encodings.
Everyday utility — students reach for the
GPA calculator and
grade calculator; diners for the
tip calculator; and there are also tools for
sleep cycles,
bra size,
shoe size conversion, and
golf handicap.
Weather and transportation — check how conditions actually feel with
wind chill,
heat index, and
dew point; plan trips with
fuel cost,
gas mileage, and
mileage calculators. And when the work is
done, the dice roller and
love calculator are in
Entertainment/Anecdotes.
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A note on accuracy
The tools in this section follow the definitions behind each subject. Date and time calculators use
the proleptic Gregorian calendar and count actual calendar days, so leap years are handled exactly.
Unit conversions use the exact defined factors — an inch is exactly 25.4 millimeters and an
international pound is exactly 0.45359237 kilograms — so a conversion only ever rounds at the final
display step. Building estimators report the material a job needs and, where suppliers sell in whole
units, round up the way a supplier would; treat those figures as planning estimates and add your own
waste allowance for cutting and breakage. Weather calculators implement the standard published
formulas (the National Weather Service wind chill and heat index equations), and the password
generator creates passwords locally in your browser using cryptographic randomness — nothing is
transmitted or stored.
FAQ
Are these calculators free?
Yes — no sign-up, and everything runs in your browser. Nothing you type is sent to a server.
What kinds of tools are in the Other section?
Everything that does not belong to finance, fitness, or math: date and time calculators, building and housing estimators, unit conversion and measurement tools, electronics calculators, internet utilities like the IP subnet calculator and password generator, weather calculators, transportation tools, and a few for fun.
How accurate are the results?
Date and time tools use the proleptic Gregorian calendar and exact day counts. Conversions use the exact defined factors (an inch is exactly 25.4 mm, a pound exactly 0.45359237 kg). Building estimators round material quantities up the way suppliers sell them, and the notes on each page say when a result is an estimate.