Middle age is typically defined as the period from 40 to 65 years, and old age officially begins at 65 years and older in most developed countries.
What Is Middle Age?
Most experts and health organizations agree that middle age begins around 40 years and ends between 65 and 70 years, depending on the context.
Wikipedia (2025 update) defines middle age as ranging from 40–45 to 65–70 years, often ending around retirement age. (Source)
The APA Dictionary of Psychology categorizes “middle adulthood” as approximately 36–64 years. (Source)
Demographic discussions and generational studies often use the range 45–64 years to define middle-aged individuals. (Source)
Summary: In 2025, 40–65 years is the most widely accepted range for middle age.
What Is Old Age?
In most countries, old age officially begins at 65, especially in terms of health care, retirement, and social services.
Wikipedia (2025) cites 65 years as the standard starting point for old age in developed nations.
The World Health Organization (WHO) and United Nations sometimes define older adults as 60+, especially in global and lower-income settings.
(Source)
In the U.S., agencies like the CDC and Social Security Administration use 65+ for older adult health statistics and benefits. (Source)
Summary: 65 years and older is the official and widely recognized start of old age in most modern systems.
Final Quick View
| Life Stage | Age Range (Years) |
|---|---|
| Middle Age | 40–65 years |
| Old Age | 65+ years |