An age band is a range of ages used by insurers to determine premium rates. Rather than setting a unique premium for every single age, insurers group ages into bands — for example, 18-24, 25-29, 30-34, and so on in five-year increments. Your premium stays the same while you remain within an age band and increases when you move into the next band at renewal. Age bands reflect the fact that health care costs generally increase with age. Premiums can increase significantly at certain age thresholds, particularly after age 50 and again after age 60. Understanding age bands helps you anticipate future premium increases and compare plans accurately. Some insurers use narrower bands (three-year increments) or single-age pricing, which results in smaller but more frequent increases.