CALCULATE WITH CONFIDENCE

Arithmetic Operations

Long Addition Calculator

Add whole numbers or decimals exactly, align every place value, and inspect each carrying step in the written calculation.

Exact written addition

Enter the numbers to add

Up to 50 numbers
Digits and one optional decimal point.
Digits and one optional decimal point.

Exact total

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Enter at least two valid non-negative numbers to see the exact total and written carrying steps.

Your entries are calculated in this browser and are not submitted to 365CALCS.COM.

Quick guide

How to use the long addition calculator

  1. Enter one non-negative whole number or decimal in each labelled field.
  2. Add more fields when you need to total more than two numbers.
  3. Read the exact total and the place-value columns as soon as every entry is valid.
  4. Open the column steps to inspect each carry, or copy the exact result.

Exact decimal arithmetic

Why the decimal result remains exact

The calculator aligns every decimal place and adds the digits as integers. It does not convert your entries into ordinary browser floating-point numbers, so values such as 0.1 and 0.2 total exactly 0.3.

The result preserves the greatest number of decimal places entered. For example, 1.20 + 2.3 is displayed as 3.50, making the original decimal scale visible.

Worked example

Add 347.25, 89.90, and 2.85

Align the decimal points, add from the hundredths column toward the left, and carry whenever a column total reaches ten or more. The exact total is 440.00.

347.25 + 89.90 + 2.85 = 440.00

Supported inputs

Precision and limits

Whole numbers and decimals

Use digits with one optional decimal point and no grouping separators.

Exact large values

Each addend can contain up to 200 digits, including up to 100 decimal places.

Up to 50 addends

Add several values in one written calculation without intermediate rounding.

Clear scope

Negative values, fractions, scientific notation, units, and currency symbols are not accepted here.