How to Use the Stock Cumulative Return Calculator
Simply adding up daily percentage changes doesn't reflect actual investment performance, because stock prices move relative to the previous day's close — returns compound rather than add. This calculator takes daily percentage changes, separated by commas or new lines, and calculates both the compounded cumulative return and the simple sum for comparison.
For example, a +10% day followed by a -10% day sums to 0%, but the actual cumulative return is (1.1×0.9-1)×100 = -1%, a loss. The gap between the simple sum and the true cumulative return widens with more frequent and larger swings. To know your real return over a holding period, always check the compounded cumulative figure rather than the simple sum.
Frequently Asked Questions
Cumulative return compounds each day's return multiplicatively, so it diverges from a plain sum, especially with repeated ups and downs.
Enter each day's percentage change in order, separated by commas or new lines.
Yes, enter down days as negative numbers and they are factored in automatically.