Convert Hand (hand) to Megameter (Mm) instantly.
About these units
Hand (hand)
The hand is a traditional unit of length equal to 4 inches, historically used to measure the height of horses. Its origins go back thousands of years, when people commonly relied on body-based measurements. While early hands varied from culture to culture, the modern standardized hand—set at exactly 4 inches—was adopted to bring uniformity to equine measurement worldwide. When measuring a horse, the height is taken at the withers, the ridge between the shoulder blades, because this location provides a stable and consistent point unaffected by head movement. Horse heights are often written in a mixed-unit style: for example, "15.3 hands" means 15 hands plus 3 inches, not 15.3 × 4 inches. Though rarely used outside the world of horsemanship, the hand has become deeply embedded in equestrian culture. It provides a system that is intuitive, easy to visualize, and respectful of longstanding tradition. In modern times, even highly scientific equine breeding and veterinary studies continue to quote measurements in hands.
Megameter (Mm)
The megameter, measuring one million meters (1,000 kilometers), is useful for describing large geographical or geophysical distances on planetary scales. Earth's radius (approximately 6.37 Mm) and the thickness of atmospheric layers can be expressed effectively in megameters. This unit provides a clean and compact way to represent massive distances without resorting to scientific notation. The megameter also appears in discussions of communication signals, satellite orbits, and especially planetary science. While kilometers are still more common in public-facing contexts, megameters offer a more mathematically elegant representation for large calculations. They provide a middle ground between human-scale geography and astronomical units.