Math Calculator Hub
Accurate mathematical tools for proportions, ratios, statistics, and more. Reverse-solve any formula — enter the values you know, get the value you need.
Available Math Calculators
Proportion Calculator
Solve any proportion (A/B = C/D) for a missing value, calculate sample proportions in statistics, and apply proportions to a population. Free, instant, and accurate.
Pixels to Inches Calculator
Convert pixels to inches, inches to pixels, and calculate screen PPI from resolution. Covers web (96 PPI), print (300 DPI), and any custom resolution. Free and instant.
Average Calculator
Calculate the average (arithmetic mean) of any list of numbers instantly, along with the sum, count, min, and max.
Final Grade Calculator
Calculate a weighted course grade from categories, find what score you need on your final exam to hit a target grade, or convert points earned into a percentage and letter grade.
Peer-Reviewed Mathematical Standards
Every formula in our math calculators is sourced from established mathematical standards and peer-reviewed references. Proportion calculations use the cross-multiplication rule (A × D = B × C); sample proportion follows the statistical definition p̂ = x/n used in inferential statistics.
Read full methodology specificationsPrecision: All calculations run in double-precision floating-point arithmetic directly in your browser. No data is transmitted to any server.