Financial

PDURATION Function in Excel

Returns the number of periods required for an investment to reach a specified value.

Syntax

  • =PDURATION(rate, pv, fv)

Arguments

  • rate (required): Interest rate per period
  • pv (required): Present value
  • fv (required): Future value

Examples

  • =PDURATION(0.025, 1000, 2000) - Periods to double - Result: 28.07

PDURATION modeling tips

  • Align rate and period units (annual rate ÷ 12 for monthly models).
  • Use consistent cash-flow signs (outflows negative, inflows positive).
  • Hub: [Financial functions guide](/guides/excel-financial-functions-guide/).

Common errors

  • #NUM! if rate <= 0

Use cases

  • Investment planning
  • Goal setting
  • Time to target

Frequently asked questions

  • What is PDURATION used for? PDURATION calculates how many periods it takes for an investment to reach a target value at a given interest rate. It answers 'How long until my money doubles?' or 'When will I reach my savings goal?'
  • How do I calculate time to double my money? Use =PDURATION(rate, 1, 2) where 1 is current value and 2 is double. At 7% annual return: =PDURATION(0.07, 1, 2) = 10.24 years. This is more precise than the Rule of 72 (72/7 ≈ 10.3 years).
  • How is PDURATION different from NPER? PDURATION calculates time for a lump sum to grow (no periodic payments). NPER calculates periods for a series of payments to reach a goal. Use PDURATION for 'how long to grow $10K to $50K'; use NPER for 'how many $500 payments to reach $50K'.

Editorial review

  • Reviewed by Excel.Directory Editorial Team. Updated May 2026.