Basic Tool
Calculate common arithmetic operations using two numbers or an expression. Explore percentages, powers, remainders, averages and extrema, control decimal display and rounding, review working steps and number comparisons, and export results without server-side storage.
Table of Contents
Highlights
- Two-number arithmetic and multi-step expression modes
- Eleven operations, including percentages, powers and remainders
- Adjustable decimal places and rounding methods
- Step-by-step working and visual number comparisons
- CSV, JSON and TXT exports plus result copying
How Basic Tool Works?
In two-number mode, enter a first value a and second value b, then select an operation. Addition, subtraction, multiplication and division use their ordinary arithmetic definitions. Division and remainder require a non-zero second value. Powers use a raised to b.
| Operation | Calculation |
|---|---|
| Addition | a + b |
| Subtraction | a − b |
| Multiplication | a × b |
| Division | a ÷ b |
| Power | ab |
| Remainder | a % b (JavaScript remainder) |
| Percentage of | (a ÷ 100) × b |
| Percentage change | ((b − a) ÷ |a|) × 100% |
| Arithmetic mean | (a + b) ÷ 2 |
| Minimum / Maximum | Smaller / larger of a and b |
For example, percentage change uses the absolute value of the starting number, so the sign represents the direction from a to b even when the starting number is negative:
Expression mode evaluates numbers, parentheses, unary signs, powers (^), multiplication (*), division (/), remainder (%) and addition or subtraction. Powers precede unary signs; multiplication, division and remainder are handled before addition and subtraction. Scientific notation such as 2e3 is accepted. Select automatic display (up to ten decimal places) or a fixed number of places with nearest, down, up or towards-zero rounding. Working steps, a summary table and, in two-number mode, an absolute-magnitude bar comparison accompany the result.
Practical Use Cases
Students: Check sums, differences, products, quotients, powers and multi-step expressions while reviewing the displayed working.
Retailers: Work out a percentage of a price or compare an earlier figure with a later one using percentage change.
Office staff: Find the mean, minimum or maximum of two figures and export a calculation summary as CSV, JSON or TXT.
Developers: Test arithmetic expressions, signed remainders and exponentiation with decimal or scientific-notation inputs.
Households: Compare two amounts visually, swap their order for subtraction or division, and choose how many decimal places to display.
Accuracy and Limitations
Calculations use JavaScript double-precision floating-point numbers, so some decimal results are approximate and large or tiny values can lose precision. Inputs and results must be finite; division by zero, zero-baseline percentage change and non-real powers are rejected. The expression field is limited to 500 characters and 200 tokens, with restricted nesting. In expressions, % is remainder, not percentage; negative remainders follow JavaScript sign rules. The chart displays absolute magnitudes rather than signed directions. Fixed-decimal rounding affects the displayed value, and automatic formatting shows at most ten fractional digits.
