Quick guide
How to use this calculator
- Enter the first addend.
- Enter the second addend.
- Read or copy the exact sum.
Calculation method
Align place values, then add
Addition combines the two values. Decimal places are aligned so tenths are added to tenths, hundredths to hundredths, and so on.
The displayed result preserves at least the greatest decimal scale entered, so 0.10 + 0.2 is shown as 0.30.
Worked example
Add 12.50 and 3.2
Align 3.2 as 3.20 and add corresponding place values.
12.50 + 3.20 = 15.70
Supported inputs
Precision and limits
Exact decimal input
Each value may contain up to 200 digits, including up to 100 decimal places.
No hidden rounding
Accepted values use integer-backed decimal arithmetic rather than binary floating-point math.
Clear syntax
Enter plain decimal notation without grouping separators, fractions, or scientific notation.
Private by default
Your entries are calculated in this browser and are not submitted with the calculation.