Number & Arithmetic Calculators
10 tools in this collection — free, instant, and private in your browser.
Number and arithmetic calculators cover the foundational operations that appear constantly in mathematics, programming, and everyday problem-solving. Whether you are checking divisibility, finding a modular remainder, simplifying a fraction, or exploring prime numbers, these tools deliver precise answers quickly and explain the underlying method so you understand why the result is what it is.
Integer and divisibility tools form the core of this category. The GCD Calculator finds the greatest common divisor of two or more integers — the largest number that divides all inputs without a remainder — which is essential for simplifying fractions and solving Diophantine equations. The LCM Calculator finds the least common multiple, the smallest positive integer divisible by all inputs, which is needed for adding fractions with unlike denominators and scheduling repeating events. The Prime Number Checker determines whether a given integer is prime using trial division or more efficient algorithms for larger values. The Modulo Calculator returns the remainder after division, a fundamental operation in cryptography, hashing, and cyclic scheduling.
Exponentiation and root calculators handle the other side of multiplicative arithmetic. The Power Calculator computes any base raised to any exponent, including fractional and negative exponents. The Nth Root Calculator generalizes the square root to any degree, useful in geometry, statistics, and compound growth formulas. The Factorial Calculator computes n! (the product of all positive integers up to n), which appears throughout combinatorics and probability. The Logarithm Calculator solves for the exponent that produces a given value in a specified base — the inverse of the Power Calculator — with support for natural log (base e) and common log (base 10).
Utility calculators complete the set. The Rounding Calculator rounds a number to any specified number of decimal places or significant figures using standard, floor, or ceiling rules. The Sum Calculator quickly totals a list of numbers, handy for adding up a column of values without a spreadsheet.
- Use GCD before simplifying fractions and LCM before adding unlike fractions.
- Use Factorial and the Power and Logarithm calculators for combinatorics, probability, and any exponential model.
- Use Modulo for programming tasks, cyclic patterns, and divisibility checks.
All calculators in this group work with exact integer arithmetic or high-precision floating point where applicable. For very large factorials or roots, results are expressed in scientific notation to maintain readability.
All number & arithmetic calculators
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| Tool | What it does |
|---|---|
| Factorial Calculator | Calculate the factorial of any non-negative integer (n!). |
| GCD Calculator | Find the Greatest Common Divisor (GCD) of two integers instantly. |
| LCM Calculator | Find the Least Common Multiple (LCM) of two integers instantly. |
| Logarithm Calculator | Calculate the logarithm of any number with any base, including log base 2, 10, and e. |
| Modulo Calculator | Calculate the remainder (modulo) of dividing one number by another. |
| Nth Root Calculator | Calculate the nth root of any number (square root, cube root, etc.). |
| Power Calculator | Calculate any base raised to any exponent (base^exponent). |
| Prime Number Checker | Check whether any integer is a prime number instantly. |
| Rounding Calculator | Round any number to a specified number of decimal places. |
| Sum Calculator | Add up a comma-separated list of numbers to find the total sum. |
Frequently asked questions
- What is the difference between GCD and LCM?
- The GCD (greatest common divisor) is the largest integer that divides both numbers evenly; it is used to simplify fractions and reduce ratios. The LCM (least common multiple) is the smallest integer that both numbers divide into evenly; it is used to find a common denominator when adding fractions. The two are related by the identity: GCD(a,b) multiplied by LCM(a,b) equals a multiplied by b.
- When is the modulo operation useful?
- Modulo (the remainder after division) is used in programming for tasks like wrapping an index within an array, determining whether a number is even or odd (n mod 2), implementing hash functions, generating cyclic sequences, and performing calendar arithmetic such as finding what day of the week a date falls on.
- Why do factorials grow so fast?
- Factorial growth is superexponential — faster than any exponential function. 10! is 3,628,800, but 20! exceeds 2 quadrillion and 100! has 158 digits. This rapid growth is why combinatorics problems quickly involve astronomically large numbers even for modest input sizes, and why approximation formulas like Stirling's approximation are used in practice for large n.