Defined term
Internal rate of return
Internal rate of return is a discount rate at which the net present value of a specified cash-flow series equals zero, when such a solution is defined.
Also known as IRR
economics · Concept code GS-CONCEPT-074 · Last verified August 20, 2026
Definition and boundaries
Definition
Internal rate of return is a discount rate at which the net present value of a specified cash-flow series equals zero, when such a solution is defined.
Definition claim verification: Verified August 20, 2026
In plain language
Use Internal rate of return only after the cash-flow perspective, timing, contract structure, included costs, and omitted items are made explicit.
What it is not
It is not an annual savings rate, loan APR, or guaranteed investment return.
Decision context
Why it matters
Cash-flow sign patterns can produce no solution or multiple solutions, and the metric omits an external reinvestment assumption unless one is added separately.
Decision-context claim verification: Verified August 20, 2026
Information boundary
This page provides general educational context, not a site design, production guarantee, utility determination, contract interpretation, legal opinion, tax conclusion, or individualized financial advice. Verify property, equipment, utility, jurisdiction, program, and agreement details before acting.
Concept relationships
Affects
- Payback periodPublished conceptInternal rate of return can affect how Payback period is evaluated
Primary sources
- National Renewable Energy Laboratory: System Advisor Model Help
Revision System Advisor Model 2023.12.17 help · Source event as of December 17, 2023 · Ontology accessed August 20, 2026 · Ontology verified August 20, 2026
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