Math & Converter Calculators
13 free tools for percentages, unit conversion and everyday number work.
Percentage Calculator
Percentage increase, decrease and ratio
Calculate →Standard Deviation Calculator
Standard deviation and variance of a data set
Calculate →Calculator
Basic arithmetic calculator
Calculate →Scientific Calculator
Trigonometry, logarithms and exponents
Calculate →Mean, Median, Mode Calculator
Mean, median and mode of a data set
Calculate →Square Meter Calculator
Room and floor area in square meters
Calculate →Weight Converter
Convert between kg, pounds, ounces, grams and tonnes
Calculate →Length Converter
Convert between meters, miles, inches, feet, yards and km
Calculate →Dimensional Weight Calculator
Dimensional weight for shipping and cargo
Calculate →Roman Numeral Converter
Convert numbers to Roman numerals
Calculate →Random Number Generator
Generate random numbers for draws and games
Calculate →Password Combination Calculator
Password security strength and combination count
Calculate →Coin Flip
Virtual coin toss
Calculate →Practical Tools for Everyday Math
The percentage calculator is the most used tool in this category. It handles discounts, raises, VAT and rate-of-change calculations on one screen. On the statistics side, the mean-median-mode and standard deviation tools show a dataset's typical value and spread. When a distribution is skewed, the results screen tells you that the median is more reliable than the mean.
The unit converters (length, weight) work in both metric and imperial. If you ship packages, the dimensional weight tool calculates volumetric weight. Carriers bill whichever is larger, actual or dimensional weight, so bulky but light parcels can cost more than expected. The password combination calculator shows how many combinations a password has and roughly how long a brute-force attack would take to crack it.
The scientific calculator supports trigonometry, logarithms and exponents. The random number generator and coin flip tools give an instant result in your browser for draws and decisions.