Signal Lab

IRR / XIRR Calculator

An internal rate of return calculator for periodic cash flows, with optional XIRR dates.
It measures IRR (and date-based XIRR when spacing is uneven) vs your hurdle.
Use it to compare project yield to the hurdle before you lock capital.

Investment & Return What-ifs

Signal Lab · Model

IRR / XIRR Calculator

IRR (internal rate of return) — the rate that zeros NPV for periodic cash flows. Optional XIRR (Excel date-based IRR) when you supply actual dates (uneven spacing). Compare to your hurdle.

Illustrative sample (−100k then +30k × 5 · hurdle 10%). Not financial advice.

Cash flows, hurdle, and optional dates

CF0 is typically negative (outlay). Dates unlock XIRR. Persist locally · Jump to results

Optional dates (YYYY-MM-DD) for XIRR — leave blank to skip XIRR.

IRR vs hurdle

Accept if IRR ≥ hurdle. XIRR appears when all six dates are filled.

Equations

  • IRR — rate r where Σ CFt ÷ (1+r)t = 0 for t = 0…5
  • XIRR — rate r where Σ CFi ÷ (1+r)daysi/365 = 0 (actual day counts)
  • SpreadVsHurdle = IRR − Hurdle · Accept if IRR ≥ Hurdle

How this is calculated
  • IRR (internal rate of return) — solved by Newton–Raphson / bisection so NPV at that rate is zero
  • Important: IRR assumes interim cash flows are reinvested at the IRR itself — often optimistic versus a realistic reinvestment rate
  • XIRR uses actual day counts between dates; leave dates blank to skip XIRR
  • Spread vs hurdle = IRR − HurdleRate; Accept when IRR ≥ hurdle

Illustrative — not financial advice. Pair with NPV for the currency impact at a given rate.

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