Use this calculator to verify a hand calculation, normalize a value before another tool, or make the exact arithmetic convention explicit in a reproducible workflow.

First number

The first number to add.

Second number

The second number to add.

The formula below determines the tool output. Sum: The sum of the two input numbers.^[1]

Calculations use JavaScript number arithmetic. Binary floating-point representation can make some decimal results inexact, and values outside the supported numeric range can overflow or lose precision. Round only for presentation unless the selected rounding tool is itself the intended operation.

Use the inverse operation to check a result when one exists: addition pairs with subtraction, multiplication with division, and powers with roots. For rounding or normalization tools, retain the unmodified value when later calculations still require full precision.

• Add N Numbers

  Add a list of finite or extended-real numbers.

• Sum Calculator

  Sum comma- or line-separated values, optionally interpreting individual Latin letters as ASCII values.

• Subtract N Numbers

  Subtract each subsequent finite or extended-real number from the first number.