Payback Period Calculator
Find out how long an investment takes to pay back its initial cost from its cash flows.
Try an example
4 years
About this calculator
What Is the Payback Period?
The payback period is the length of time it takes an investment to earn back its initial cost from the cash it generates. If you spend $50,000 on a new machine that adds $10,000 of net cash flow each year, the payback period is five years. It is one of the simplest and most popular ways to judge a project, a purchase or a business idea: the shorter the payback, the sooner you are out of the red and the less time your money is exposed to risk.
How to Calculate It
For even annual cash flows: Payback period = Initial investment ÷ Annual net cash flow. When cash flows differ from year to year, add them up year by year until the running total reaches the investment, and take the fraction of the final year that is needed. For instance, with a $20,000 outlay and cash flows of $8,000, $7,000 and $9,000, the cumulative total passes $20,000 during year three: 8,000 + 7,000 = 15,000, and the remaining 5,000 ÷ 9,000 gives about 0.56 of that year, so the payback is roughly 2.56 years.
Worked Example
A $20,000 investment generating $5,000 per year in cash flow pays back in 4 years.
Understanding Cash Flow
Cash flow is the money moving in and out of a project or business. Inflows — revenue, savings, or reduced costs — increase liquid assets, and outflows — expenses, rent, taxes, maintenance — reduce them. For payback, you want the net amount per period: inflows minus outflows. Make sure you count only real cash, not accounting profits.
Discounted Payback Period
The simple version treats a dollar in year five as equal to a dollar today. The discounted payback period corrects that by discounting each future cash flow back to its present value at a chosen rate before adding them up (see the Present Value Calculator). It always gives a longer period than the simple version, and it is a more realistic test of whether an investment truly pays for itself.
Strengths and Limits
- Pros: easy to compute and explain, and a good quick screen for liquidity and risk.
- Cons: it ignores everything that happens after payback, so a project with huge long-term returns can lose to a quick small one. It also ignores the time value of money unless discounted.
Use it together with measures such as return on investment and net present value, not as your only yardstick.
Worked example
A $20,000 investment generating $5,000 a year pays for itself in 20,000 ÷ 5,000 = 4 years.
Frequently asked questions
Does this account for the time value of money?
No — this is the simple payback period, which treats each year's cash flow equally. A discounted payback period would weight later cash flows less, but requires an assumed discount rate.
What counts as a good payback period?
It depends entirely on the type of investment and industry — a faster payback is generally lower-risk, but there's no universal threshold.
Does this assume the cash flow is the same every year?
Yes — for cash flows that vary year to year, you'd need to add them up cumulatively until they cover the initial investment instead.
