Addition of 4 digits calculator is a free and simple online tool which computes the sum of 2 three-digit numbers. In this 4 digit addition calculator, there are a total of 8 input boxes (four in each row). In the first row, “First Number” is mentioned and in the second row, “Second Number” is mentioned.
To calculate the sum of 2 four-digit numbers, first, enter the first number in the first row i.e. across “First Number” box. Similarly, enter the second number in the second row. The input boxes are arranged as “thousands place”, “hundreds place”, and “units place”. It should be noted that only three digits number should be entered.