Python implementation for calculating the Standard Precipitation Index (SPI) and Standard Precipitation Evapotranspiration Index (SPEI) - e-baumer/standard_precip ...

How to calculate return on investment (ROI), the money an investment made relative to its cost, in Microsoft Excel.

Excel and Google Sheets have three functions to calculate the internal rate of return: IRR, XIRR, and MIRR. Learn how these functions can calculate investment returns.