IRR or Irr may refer to:

Finance

* Implied repo rate, in the futures market *

Internal rate of return Internal rate of return (IRR) is a method of calculating an investment’s rate of return. The term ''internal'' refers to the fact that the calculation excludes external factors, such as the risk-free rate, inflation, the cost of capital, or fin ...

, a profitability metric *

Iranian rial The rial ( fa, ریال ایران, riyâl-è Irân; sign: ﷼; abbreviation: Rl (singular) and Rls (plural) or IR in Latin; ISO code: IRR) is the official currency of Iran. There is no official symbol for the currency but the Iranian standar ...

, currency of Iran by ISO 4217 code *

Interest rate risk In finance and economics, interest is payment from a borrower or deposit-taking financial institution to a lender or depositor of an amount above repayment of the principal sum (that is, the amount borrowed), at a particular rate. It is distinc ...

, financial risk from fluctuating interest rates

Organisations

* Incident Response Regiment (Australia), an emergency response agency * Institute of Race Relations, a policy institute *

Institute for Religious Research The Institute for Religious Research (IRR) is an American Christian apologetics and counter-cult organization based in Cedar Springs, Michigan. It declares itself to be a non-denominational, non-profit Christian foundation for the study of rel ...

, an apologetics organization *

Iraqi Republic Railways Iraqi Republic Railways Company (IRR; ar, الشركة العامة لسكك الحديد العراقية) is the national railway operator in Iraq. Network IRR comprises of . IRR has one international interchange, with Chemins de Fer Syrien ...

, a transportation operator * South African Institute of Race Relations, a think tank

Science and technology

* Image rejection ratio, a radio metric * Interrupt Request Register, a register used for managing interrupts in programmable interrupt controllers *

Internet Routing Registry An Internet Routing Registry (IRR) is a database of Internet route objects for determining, and sharing route and related information used for configuring routers, with a view to avoiding problematic issues between Internet service providers. The ...

, a network routing database * Irregular galaxy, a galaxy that does not have a distinct regular shape

Other

Incidence rate ratio In epidemiology, a rate ratio, sometimes called an incidence density ratio or incidence rate ratio, is a relative difference measure used to compare the incidence rates of events occurring at any given point in time. It is defined as: : \text = \ ...

, a statistic derived from a Poisson regression model * Individual Ready Reserve, a personnel status of the United States Military *

Infusion-related reaction Cytokine release syndrome (CRS) is a form of systemic inflammatory response syndrome (SIRS) that can be triggered by a variety of factors such as infections and certain drugs. It refers to cytokine storm syndromes (CSS) and occurs when large numb ...

or infusion reaction, a form of systemic inflammatory response syndrome caused by some diseases or drugs * Inner Ring Road (disambiguation) * Inter-rater reliability {{disambiguation