An
intermediate-range ballistic missile (
IRBM) is a
ballistic missile with a
range of 3,000–5,500 km (1,864–3,418 miles), between a
medium-range ballistic missile (MRBM) and an
intercontinental ballistic missile (ICBM). Classifying ballistic missiles by range is done mostly for convenience, in principle there is very little difference between a low-performance ICBM and a high-performance IRBM. The range definition used here is used within the U.S.
Missile Defense Agency. Some other sources include an additional category, the
long-range ballistic missile (
LRBM), to describe missiles with a range between IRBMs and true ICBMs. The more modern term
theater ballistic missile encompasses IRBMs, MRBMs and SRBMs, including any ballistic missile with a range under .