🔢 Number Tools
Free calculators and converters for everyday number problems. All run instantly in your browser.
Percentage Calculator
Calculate percentages instantly — find X% of Y, what percentage X is of Y, percentage increase/decrease, and reverse percentages.
Roman Numerals
Convert numbers to Roman numerals or Roman numerals to numbers. Supports 1 to 3999. Shows a full symbol breakdown.
Random Number Generator
Generate random numbers within any range. Single or bulk. Unique numbers, no repeats mode. Includes a dice roller with D4 through D100.
Aspect Ratio
Find missing image dimensions from a ratio, or calculate the aspect ratio from width and height. Common ratio presets included.
Tip Calculator
Calculate the tip on any bill and split it between any number of people. Tip slider, preset buttons, per-person breakdown.
Prime Checker
Check if any number is prime. List all primes in a range. Find the next prime. Shows full factorisation.
LCM & GCF
Find the Lowest Common Multiple (LCM) and Greatest Common Factor (GCF/HCF) of up to 6 numbers. Shows prime factorisation.
Statistics Calculator
Calculate mean, median, mode, range, variance and standard deviation from any dataset. Paste numbers and get full stats instantly.
GCF / LCM Calculator
Calculate the Greatest Common Factor (GCF) and Lowest Common Multiple (LCM) of up to 10 numbers. Shows prime factorisation.
Scientific Notation
Convert numbers to/from scientific notation. Shows E notation and engineering notation. Handles very large and very small numbers.
Ratio Simplifier
Simplify ratios to lowest terms. Scale a ratio to any total. Compare two ratios for equivalence. Shows decimal and percentage forms.
Compound Interest
Calculate compound interest for any principal, rate and period. Monthly or annual compounding. Compare simple vs compound growth.
Binary Converter
Convert binary to decimal, hexadecimal and octal. Convert decimal to binary. Shows working and bit breakdown. Free.
Decimal to Fraction
Convert any decimal to a fraction in lowest terms. Shows exact fraction, mixed number and step-by-step working. Free and instant.
Fraction Calculator
Add, subtract, multiply and divide fractions with step-by-step working. Handles mixed numbers and simplification. Free.
% Difference
Calculate the percentage difference between two numbers. Shows increase, decrease, and absolute vs relative change. Free and instant.
Number Sequence
Generate arithmetic, geometric, Fibonacci, square and prime sequences. Choose start, end and step. Copy the list. Free.
Average Calculator
Calculate arithmetic mean, geometric mean and weighted average. Handles negatives and decimals. Free.
Fibonacci
Generate Fibonacci numbers up to any term. Shows the sequence, ratios approaching the golden ratio, and the formula. Free.
Prime Factors
Find the prime factors of any number. Shows the factor tree and prime factorization notation. Handles numbers up to 10 billion. Free.
% Difference
Calculate the percentage difference, increase or decrease between two numbers. Shows formula and steps. Free.
Odds Converter
Convert between fractional, decimal, American (moneyline) and implied probability betting odds. Free.
Factor Tree
Break any number into its prime factors with a visual factor tree. Shows all factors and prime factorisation. Free.
Dice Roller
Roll virtual dice. Supports d4, d6, d8, d10, d12, d20, d100. Multiple dice at once. RPG notation. Free.
Number Spinner
Animated number wheel that picks a random number from your chosen range. Great for classroom and games. Free.
Tip Table
Quick reference table showing tips at 10%, 12%, 15%, 18%, 20% and 25% for any bill amount. Free.
ASCII
Convert text to ASCII codes (decimal, hex, binary) and back. Free.
% Change
Calculate percentage change, increase or decrease between two values. With negative handling. Free.