IRR計算機

Calculate Internal Rate of Return, NPV, payback period, and profitability index from your initial investment and cash flows.

あなたの詳細

$

Enter expected cash inflow each year (e.g. 25000).

年 1
$
年 2
$
年 3
$
年 4
$
年 5
$
%

Used for NPV and investment decision.

Enter your initial investment, annual cash flows, and discount rate. Click Calculate to see IRR, NPV, payback period, and cash flow analysis.

完全なユーザーガイド

What is IRR?

The Internal Rate of Return (IRR) is the discount rate that makes the Net Present Value (NPV) of all cash flows from a project equal to zero. It represents the expected annual return of the investment. If IRR is greater than your required return (cost of capital), the project is typically considered acceptable.

NPV = 0 = CF₀ + CF₁/(1+IRR) + CF₂/(1+IRR)² + …

What Your Results Mean

IRR

The annualized return implied by your cash flows. Compare it to your discount rate to decide: Accept (IRR > rate), Reject (IRR < rate), or Indifferent (IRR = rate).

NPV

Net Present Value at your chosen discount rate. Positive NPV means the investment adds value; negative means it destroys value.

Payback & Profitability Index

Payback is how many years until cumulative cash flows recover the initial investment. Profitability Index is PV of inflows ÷ initial investment; above 1 is good.

この計算機の使い方

  1. Enter your initial investment (outflow, e.g. cost of the project)
  2. Enter expected cash inflow for each year; use 'Add year' to add more periods
  3. Enter your required return or discount rate (e.g. 10 for 10%%)
  4. Click Calculate to see IRR, NPV, payback, and analysis

数式

NPV = Σ CFₜ / (1 + r)ᵗ

IRR is the r that makes NPV = 0. Solved numerically (e.g. Newton-Raphson).

重要な注意事項

  • IRR can be misleading with non-conventional cash flows (multiple sign changes). Use NPV for decision-making when in doubt.
  • For education only. Not financial or investment advice.

When to Use IRR

  • Evaluating projects, acquisitions, or capital investments
  • Comparing investments with different sizes and timelines
  • Setting hurdle rates and investment decisions

📤 Share This Tool