ComboCurve: ARIES Discounted Cashflow: Comparison (with Excel workbook)
Which cashflow discounting methods match between ComboCurve and ARIES?
- In ComboCurve, choose your Project and Scenario and go to General Options and set:
- Discounting Method to Yearly (N=1), and
- Cash Accrual Time = Mid Month
- In ARIES under Economics...Setup...Current Input Settings, Present Worth Component...Discount Method... choose Monthly (and ensure Discount Date = Effective Date)
Because the ARIES
Monthly discounting method discounts from mid-month, regardless of timeframe settings, the
Yearly (N=1) with
Mid-Month discounting has been found empirically to match ARIES. For a detailed comparison of discounting methods, please see the attached spreadsheet.

Excel Spreadsheet Comparison of Discount Factors from ComboCurve and ARIES
- This macro-enabled Excel workbook contains actual output discount factors using each of the various methods from ComboCurve and ARIES, along with rollups to yearly.
- If the above link does not work, navigate here and download the attachment.
- Also included are cell formulas that demonstrate how each application calculates discounting.