IRR Calculator

Estimate the Internal Rate of Return (IRR) for an investment with equal annual cash flows using bisection. Free, instant, no signup.

years
Formula: NPV(r) = −Investment + Σ Cashflow/(1+r)^t = 0 → solve for r
  • r = IRR (solved by bisection)
  • t = year index 1..n

How to use the IRR Calculator

  1. Enter your values. Fill in the fields with your numbers.
  2. Calculate. Press Calculate to run the irr calculator.
  3. Use the result. Copy the result or try a related tool next.

Why use our IRR Calculator

Instant results. Enter your figures and the irr calculator returns an answer in seconds.
Free & private. Runs in your browser — no signup, and nothing is sent to a server.
Accurate. Uses standard formulas so you can rely on the numbers.

Free to use — premium coming soon

FREE
  • Unlimited calculations
  • Instant results
  • No signup
PREMIUM
  • Remove ads
  • Save & compare scenarios
  • Export results

About the IRR Calculator

The IRR Calculator finds the internal rate of return for a series of cash flows: the single annualized discount rate that makes the net present value of every inflow and outflow equal zero. You enter your initial outlay (a negative number, since money leaves your pocket) followed by each period's cash flow, and the tool returns the percentage rate at which the investment exactly breaks even in present-value terms. Because IRR bakes the timing of money into one figure, it is the standard yardstick for comparing projects, property deals, private-equity funds, and any plan where cash arrives unevenly over several years rather than as a single lump sum.

Reach for this calculator whenever you need to judge a multi-year investment by a single comparable number. Real-estate investors use it to score a buy-and-hold deal against a target like 8-10% for stable core assets or 15%+ for value-add plays; business owners use it to rank capital projects against their cost of capital, funding only those whose IRR clears the hurdle rate. It is also handy for sense-checking a fund's quoted return or comparing two offers with different payout schedules. Note that IRR rewards early cash: a 50% total gain over two years works out to roughly 22% IRR, while the same 50% spread over five years is only about 8%.

Under the hood, IRR cannot be solved with a single algebraic step, so the calculator solves it iteratively. It starts from a guess (often 10%), computes the NPV of your cash flows at that rate, and then refines the rate, narrowing on the value where NPV crosses zero using a Newton-Raphson or interpolation routine, exactly how spreadsheet IRR functions work. One caveat built into the math: standard IRR implicitly assumes interim cash flows are reinvested at the IRR itself, which can flatter high-return deals. When cash flows switch sign more than once, more than one rate can satisfy the equation, the well-known multiple-IRR problem, in which case MIRR or NPV is the safer guide.

Everything is computed in your browser. Your cash-flow figures are never uploaded, logged, or stored on a server, so you can model sensitive deal numbers privately and reload the page to start fresh. The result is a mathematical solution to your exact inputs, so its accuracy depends entirely on the realism of your cash-flow estimates and on using a consistent period length (yearly figures give an annual IRR; monthly figures give a monthly rate you must annualize). For sign-changing or unconventional cash-flow patterns, cross-check the answer against NPV at your own discount rate before acting on it.

Frequently asked questions

What is a good IRR?

It depends on the risk and the alternative uses of your money: an IRR only adds value when it beats your hurdle rate or cost of capital. In real estate, roughly 8-10% is typical for stable core assets and 15%+ for higher-risk value-add deals, but a 12% IRR on a safe project can beat a 20% IRR on a risky one.

How do I enter cash flows in the IRR Calculator?

Enter your initial investment as a negative number (cash going out), then list each later period's net cash flow with its correct sign, positive for money received, negative for further outlays. The periods must be equally spaced, and the IRR you get matches that spacing, so yearly figures produce an annual rate.

What is the difference between IRR and NPV?

NPV gives you a dollar value of an investment at a discount rate you choose, while IRR is the specific discount rate that drives that NPV to zero. They answer related questions, and when comparing mutually exclusive projects NPV is generally the more reliable decision rule.

Why does the calculator return more than one IRR, or none at all?

When your cash flows change sign more than once (for example, an outflow, then inflows, then another large outflow), the underlying equation can have multiple valid solutions or none. In those cases IRR is unreliable, so use NPV at your own discount rate or the modified IRR (MIRR) instead.

Does IRR assume I reinvest the cash I receive?

Yes, the standard IRR formula implicitly assumes every interim cash flow is reinvested at the IRR itself, which can overstate the return on high-IRR deals. If that assumption is unrealistic, MIRR lets you reinvest at a more conservative rate such as your cost of capital.

From our blog

Healthy Weight by Height: How to Read and Use Your Range

By the Super Simple Digital Tools Team · Updated June 2026

Most people picture a single 'goal weight', but health authorities actually define a healthy weight as a span. The reason is simple: a person of a given height can carry slightly more or less weight, depending on frame and muscle, and still be perfectly healthy. The Healthy Weight Calculator captures this by giving you a low and a high figure that bracket the recognised healthy BMI zone of 18.5 to 24.9, turning an abstract index into something you can read off a scale.

The arithmetic behind it is the BMI formula run in reverse. BMI equals weight in kilograms divided by height in metres squared. To find the weights instead of the index, you fix BMI at the two boundary values and rearrange: lower weight equals 18.5 times height squared, upper weight equals 24.9 times height squared. A person 1.60 m tall has a height squared of 2.56, so their healthy band is roughly 47 kg to 64 kg. Add a few centimetres of height and the whole window shifts upward, which is exactly why a borrowed weight target from a taller friend rarely fits.

Once you have the range, the useful question is where you want to sit within it. Landing anywhere inside 18.5 to 24.9 is considered healthy, but many people aim for the middle of their band to leave room for the normal daily swings of one to two kilograms caused by water, food and timing. If your current weight is above the top of the range, the gap to the upper bound is a modest, achievable first goal rather than the daunting jump to the lowest figure. Small targets are easier to keep.

It is worth being clear about what the number cannot tell you. BMI was designed for population screening and treats all weight the same, so it cannot see whether your kilograms are muscle or fat. A rugby player and a sedentary person of identical height and weight get the same band, even though their health picture differs. That is why clinicians pair BMI with waist circumference, blood pressure and other checks. The calculator is a fast first filter, not a diagnosis.

To get the most reliable reading, measure your height accurately without shoes and weigh yourself at a consistent time, ideally in the morning. Re-check your range only if your height changes, which for adults is rare, and track your weight against the band over weeks rather than reacting to a single reading. Used this way, the healthy weight range becomes a steady reference point that supports gradual, sustainable change instead of crash targets.

  • Measure height in bare feet and weigh yourself at the same time of day for a like-for-like comparison against your range.
  • Aim for the middle of your band rather than the bottom edge, so normal daily fluctuations of one to two kilograms do not push you out of range.
  • If you are above the range, set the upper bound as your first milestone instead of the lowest figure, then reassess.
  • Pair the result with a waist measurement, since waist size adds information about fat distribution that BMI alone cannot capture.

Read the full guide →

Tool by the Super Simple Digital Tools Team. Reviewed by our editorial team. Free to use, no signup required.

Related tools