NPV Calculator

NPV Calculator: calculate npv for your business. Formula, benchmarks, and practical tips included.

Net Present Value (NPV) is the gold standard for capital allocation decisions — it measures the total value created (or destroyed) by an investment by summing all future cash flows discounted back to today's money at the required rate of return (WACC). A positive NPV means the investment generates returns above your cost of capital and creates value; a negative NPV means it destroys value relative to your next best alternative. The Internal Rate of Return (IRR) is the discount rate at which NPV equals zero — it represents the actual annualised return on the investment and is directly comparable to your WACC or a benchmark return. Profit Margin Calculator and Markup Calculator provide related business financial analysis tools for comprehensive investment appraisal.

NPV analysis underpins virtually all sophisticated capital budgeting, from individual equipment purchases to corporate M&A decisions, infrastructure projects, and private equity transactions. The academic framework was formalised by Brealey, Myers & Allen in "Principles of Corporate Finance" — the most widely used corporate finance textbook globally. UK corporate WACC typically ranges from 8–12% according to Damodaran's industry data, though this varies significantly by sector, leverage, and risk profile. When comparing two mutually exclusive projects, always choose the one with higher NPV, not higher IRR — the IRR can be misleading for projects of different scale or duration.

Enter the initial investment (Year 0 outflow) — the total upfront capital cost including all acquisition, installation, and setup expenses.
Enter the expected annual net cash flows for each year of the project life using the dynamic row inputs. Add or remove years as needed (up to 10 years supported).
Set your discount rate — this should be your WACC (Weighted Average Cost of Capital) or your required rate of return for investments of this risk level. Typical UK corporate WACC is 8–12%.
Optionally add a Gordon Growth Model terminal value to capture the value of cash flows beyond your projection period — particularly useful for businesses and long-lived assets.
Review the NPV (accept if positive), IRR (compare to WACC), Profitability Index (accept if > 1), and the year-by-year schedule to understand the NPV build-up.

NPV and IRR formulas explained

NPV = −Investment + Σ(CF_y ÷ (1+r)^y) for y = 1 to n. Where r is the discount rate (WACC) and CF_y is the net cash flow in year y. The discount factor (1+r)^y converts future cash flows into present value — at 10% WACC, £110 in Year 1 is worth £100 today, and £161 in Year 5 is also worth £100 today.

IRR: the discount rate r* where NPV = 0. Solved numerically using Newton-Raphson iteration: start with r = 10%, compute NPV, adjust r based on the slope of the NPV curve, iterate until NPV ≈ 0. The Profitability Index = (NPV + Investment) ÷ Investment — a PI above 1 means the investment is value-accretive per pound invested.

Worked example: £200,000 investment, cash flows of £50k/£60k/£70k/£80k/£80k, WACC 10%. Year 1 PV: £50,000÷1.10 = £45,455. Year 2: £60,000÷1.21 = £49,587. Year 3: £70,000÷1.331 = £52,594. Year 4: £80,000÷1.464 = £54,645. Year 5: £80,000÷1.611 = £49,659. Total PV = £251,940. NPV = £251,940 − £200,000 = +£51,940. IRR ≈ 19.4%.

Interpreting your NPV and IRR results

The NPV rule and when IRR gives conflicting signals

The NPV decision rule is unambiguous: accept all projects with NPV > 0 (they create value) and reject all with NPV < 0 (they destroy value). When choosing between competing projects with limited capital, rank by NPV and fund from highest to lowest until capital is exhausted. The Profitability Index (NPV ÷ Investment) is useful for ranking projects of different sizes — a smaller project with PI of 1.8 may be preferable to a larger project with PI of 1.2 when capital is constrained.

The IRR should exceed your WACC for an investment to be financially attractive. However, the IRR can produce misleading rankings when comparing projects of different scale or with unconventional cash flow patterns (e.g. large outflows in later years). In these cases, the Modified IRR (MIRR) or NPV is more reliable. The UK Treasury's Green Book — used for all major government investment appraisal — mandates NPV analysis using a 3.5% social discount rate for public projects, reflecting the long-run trend growth in consumption per capita.

Business tips and best practices

Use the terminal value feature for ongoing businesses — most of the NPV of a long-lived investment comes from cash flows beyond the explicit projection period; the Gordon Growth Model captures this.
Perform sensitivity analysis by varying the discount rate ±3% — if NPV turns negative with only a small increase in WACC, the investment is fragile and warrants additional risk mitigation.
Real vs nominal analysis: if your cash flows are in nominal terms (not inflation-adjusted), use a nominal WACC; if in real terms, use a real WACC (approximately nominal WACC minus inflation).
The IRR assumes reinvestment of cash flows at the IRR itself — which is often unrealistic for high-IRR projects. MIRR reinvests at WACC and is a more conservative, defensible estimate of return.
For post-investment review, compare actual NPV to projected NPV by year — systematic over-optimism in projections ("optimism bias") is the most common cause of investment underperformance.
Include working capital movements in your cash flows — increases in receivables and inventory are cash outflows; decreases and terminal working capital recovery are inflows.

NPV analysis is used in approximately 75% of large corporation capital budgeting decisions in the UK and US (Brounen, De Jong & Koedijk; Graham & Harvey surveys).
Average UK corporate WACC is 8–12% for listed companies; unlisted SMEs typically use 12–20% to reflect higher risk and illiquidity (Damodaran industry data, 2023).
IRR should exceed WACC by at least 3–5 percentage points (the "hurdle rate premium") to compensate for optimism bias in cash flow projections (McKinsey research).
The UK Green Book mandates a 3.5% real discount rate for government project appraisal — reflecting the social time preference rate for public investments (HM Treasury, 2022).

Common mistakes to avoid

Comparing IRR directly to return on equity or earnings yield — IRR must be compared to WACC (which blends equity and debt costs), not equity cost alone.
Using the same discount rate for projects of different risk — a real estate development and an early-stage software product have very different risk profiles and should use different WACCs.
Forgetting salvage value and working capital recovery in terminal year cash flows — these can add 10–20% to NPV for asset-intensive investments.
Accepting a positive-IRR project with negative NPV — this happens with non-conventional cash flows. Always check NPV, not just IRR, before deciding.

NPV and IRR calculations are financial modelling tools for planning and educational purposes only. They do not constitute investment advice, financial advice, or a recommendation to invest in any asset, project, or security. For regulated investment activities — including fund management, securities analysis, M&A advisory, and public company transactions — analysis must be prepared by FCA-authorised professionals (UK) or equivalent regulated advisers in other jurisdictions. All projections are inherently uncertain; actual returns may differ materially from modelled estimates. This calculator uses the IFRS and UK GAAP consistent discounted cash flow methodology.