Payback Period Calculator
Work out how many years and months an investment takes to pay for itself from its cost and yearly savings or cash flows, with the discounted payback too. Use even savings, or type uneven cash flows year by year, add a discount rate, and see when the investment pays back, or that it does not within the years you check.
Your numbers
What the buyer pays now: price, installation, setup.
Net of any yearly running cost the purchase adds.
How long the savings last, or the years the buyer looks at.
For discounted payback and NPV. Use the buyer's cost of capital or hurdle rate.
Payback period
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- Payback in years
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- Total cash flows over 10 years
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Cash flows are taken at the end of each year, and the year the cost is repaid is split as if the money came in evenly through it.
A guide for a business case, not financial, tax or legal advice.
The calculation runs in your browser and ParrotNotes does not store your numbers. They sit in the page address so you can bookmark or share the result.
How the payback period is worked out
Payback is the time it takes for the cash an investment brings in to repay what it cost. The calculator takes the cost as paid now and each year's cash flow at the end of that year, adds them up year by year, and finds the year the running total turns positive. That year is split on the assumption the money comes in evenly through it: years before + amount still to recover ÷ cash flow that year.
With the same savings every year this comes to cost ÷ yearly savings. A $60,000 machine saving $18,000 a year: 60,000 ÷ 18,000 = 3.33 years, or 3 years and 4 months. Savings should be net of what the purchase adds in running costs: power, service, licences.
Uneven cash flows
Savings rarely arrive in equal amounts: a solar system makes less in a cloudy year, software saves more once the team is trained, and a machine may need an overhaul in year 4. On the cash flows by year tab, type each year's amount; a negative number is money going out that year. Penn State's course example has a second outlay in year 1 (−250 after −200 now), then 150, 180, 220 and 200: the running total turns positive in year 4 and the payback is 3.55 years.
Discounted payback
Simple payback counts a dollar in year 5 the same as a dollar today. Discounted payback divides each year's cash flow by (1 + rate) to the power of the year before adding them up, so later money counts for less. Type the buyer's discount rate, often their cost of capital or the return they require, to see it, with the NPV of the years you entered. When the discounted flows never repay the cost, the NPV is negative at that rate and the calculator says the cost is not repaid within the years given.
Payback, ROI and NPV
Payback answers how fast. ROI answers how much, as a share of the cost, and NPV answers how much in today's money at a chosen rate. A finance team usually wants all three. The ROI calculator and the NPV calculator on this site take the same numbers; the break-even calculator works the same idea in units sold instead of years.
For reps building a business case
An equipment, solar or software rep who puts a payback in the proposal gives the buyer a number to take to the person who signs. Build it from the buyer's figures, not yours: what they spend now on energy, labor, scrap or the old system, and what the purchase changes. Show the year-by-year table so finance can check it, and give the discounted figure at their rate before they ask.
What this calculator does not do
It works in whole years, with each year's cash flow at the end of the year. It does not handle tax, depreciation, financing or inflation unless you build them into the cash flows you type. If the running total turns positive and then negative again because of a later outlay, the first time it turns is the payback. The result is a guide for a business case, not financial, tax or legal advice.
Sources, each read on 2026-10-28:
More for reps building a business case: Capital equipment sales, Solar sales, B2B SaaS sales, Value-based selling.
The savings come from the buyer's own numbers
The figures that go into a business case come up on the call: what the buyer spends now on energy, labor or the old system, and what they expect to change. Record it in ParrotNotes and get a note, a summary and the action items, so their numbers are in the notes when you build the case. Free for 100 minutes of recording a month.
Get Started FreeRelated tools
- NPV CalculatorWork out the net present value of an investment from its cash flows and discount rate, with IRR, payback and a year-by-year table.Open the tool
- ROI CalculatorWork out return on investment, annualized ROI and payback period from what you put in and what you get back, for a purchase or a customer's business case.Open the tool
- Break-Even CalculatorFind the break-even point in units and revenue from fixed costs, price and variable cost, plus the sales needed for a target profit.Open the tool
- TCO CalculatorCompare the total cost of ownership of two or three options over the years you will own them: purchase, running costs, maintenance and resale.Open the tool