COLLECTION / 02
General tools
Everyday calculators and utilities for conversions, timers, dates, money, astronomy, security, and practical problem solving.
Popular / everyday
Popular general tools
Unit conversion
Unit converter
Convert common length, mass, temperature, area, volume, and speed units in one focused workspace.
Time & date
Timer & stopwatch
Run a clean countdown or stopwatch with pause, resume, and reset controls.
Time & date
Date difference & age
Find elapsed days, calendar time between two dates, or age on a chosen date.
Everyday math
Percentage calculator
Find a percentage of any value and see the same value after an increase or decrease.
Everyday math
Tip & bill split
Calculate a tip, total bill, and equal per-person share for any group size.
Money
Mortgage calculator
Estimate a fixed-rate mortgage payment, the full monthly housing cost, or a home-price budget.
Money
Loan calculator
Solve a fixed-rate loan for payment, principal, term, or interest rate and inspect every payment.
Money
Currency converter
Convert common currencies with a clearly dated reference exchange rate.
Money
U.S. inflation
Compare the purchasing power of U.S. dollars between years using CPI reference data.
Astronomy & space
Orbital period
Calculate orbital period, revolutions per Earth day, and mean motion from a central body and semi-major axis.
Security & privacy
Password generator
Generate cryptographically random passwords locally with configurable length, character groups, and transcription-safe exclusions.
Collection map
Browse by topic
Topics group the collection into focused families while every tool remains searchable from the global database.
Unit conversion
Move between metric, imperial, temperature, volume, speed, and other common units.
1 tool02Time & date
Run timers and work with ages, dates, durations, and calendar intervals.
2 tools03Everyday math
Solve percentages, splits, comparisons, and recurring day-to-day math.
2 tools04Money
Compare currency, inflation, purchasing power, and common money scenarios.
4 tools05Astronomy & space
Explore orbits, telescopes, observing geometry, and practical spaceflight relationships.
1 tool06Security & privacy
Generate and inspect security-sensitive values locally without sending them to a server.
1 toolData sources
Calculation and reference data
Converters, percentages, dates, and timers run in your browser. Currency and inflation tools show the source date beside the result so a reference value never pretends to be live market data.
How CalcDB handles sources