BYTETOOLS

NPV Calculator

Discount a full series of period cash flows to today's money at any rate, with a cumulative discounted cash flow table, profitability index and CSV export.

Cash flows

Year 0
Year 1
Year 2
Year 3
Year 4

Year 0 happens today and is never discounted. Money going out is negative, money coming in is positive.

$78.82
Net present value
$300.00
Undiscounted total
1.079
Profitability index
2.95 years
Discounted payback

Positive NPV at 10%: the cash flows are worth $78.82 more than the discount rate demands, so the project adds value at that hurdle.

Discounted cash flow table

YearCash flowFactorPresent valueCumulative
0Initial investment-$1,000.001.0000-$1,000.00-$1,000.00
1$500.000.9091$454.55-$545.45
2$400.000.8264$330.58-$214.88
3$300.000.7513$225.39$10.52
4$100.000.6830$68.30$78.82

NPV = Σ CFₜ ÷ (1 + r)ᵗ with period 0 undiscounted. Worked check: flows of −1,000, 500, 400, 300 and 100 at 10% give an NPV of $78.82. Everything is computed in your browser and nothing is uploaded. Arithmetic, not investment advice — your discount rate drives the answer.

What is the NPV Calculator?

The ByteTools NPV Calculator discounts a whole series of cash flows back to today using NPV = Σ CFₜ ÷ (1 + r)ᵗ.

  • Unlimited, irregular cash flow rows including mid-series negatives
  • Per-period discount factor, present value and cumulative total
  • Profitability index and discounted payback period
  • Clear accept/reject reading against an NPV of zero
  • CSV download of the full discounted cash flow table
  • All calculated locally — nothing is uploaded or stored

How to use the NPV Calculator

  1. 1

    Enter the initial investment as the period 0 cash flow, usually negative.

  2. 2

    Add one row per period with the expected cash flow for that period.

  3. 3

    Set your discount rate per period and choose the period label.

  4. 4

    Read the net present value, profitability index and discounted payback period.

  5. 5

    Scan the per-period table or download it as CSV.

About the NPV Calculator

The ByteTools NPV Calculator discounts a whole series of cash flows back to today using NPV = Σ CFₜ ÷ (1 + r)ᵗ. Enter the initial outlay as period 0 and then one row per period, set your discount rate, and the tool shows the net present value along with the discount factor, present value and running cumulative total for every single period.

That cumulative column is where the useful detail sits: it tells you the period at which the project first turns positive in present-value terms, which is the discounted payback period. The tool also reports the profitability index and the total undiscounted cash flow, so you can see how much of the result is timing and how much is size.

Unlike a single-sum present value calculator, this handles an irregular, uneven series of any length, including negative flows part-way through. Everything runs in your browser with nothing uploaded, and the table can be downloaded as CSV. Results are arithmetic, not investment advice — the discount rate you choose drives the whole answer.

Frequently asked questions

How do you calculate net present value?

Divide each period's cash flow by (1 + r) raised to the power of that period number, then add them all up. For flows of −1,000, 500, 400, 300 and 100 at a 10% discount rate, the NPV is $78.82, so the project adds value at that rate.

What does a positive NPV mean?

It means the project is expected to return more than your discount rate, so it adds value in present-terms money. A negative NPV means the opposite, and an NPV of exactly zero means the project earns precisely the rate you required — no more, no less.

What discount rate should I use for NPV?

Usually your cost of capital or the return you could earn on a comparable alternative. It is the single most influential input, so run the calculation at two or three rates: a project whose NPV flips sign across a plausible range deserves more scrutiny.

Should the initial investment be entered as a negative number?

Yes. Money going out is negative and money coming in is positive. Period 0 is not discounted, since it happens today, which is why the initial outlay flows straight through to the total at full value.

What is the difference between NPV and IRR?

NPV tells you how much value a project adds at a discount rate you choose; IRR tells you the discount rate at which that value would be exactly zero. They answer the same question from opposite directions and are best read together.

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