Convert Foot (ft) to Terameter (Tm) instantly.
About these units
Foot (ft)
A foot, equal to 12 inches, has been used for thousands of years and likely originated from the length of a human foot. Though early definitions varied, the modern standard foot—established internationally in 1959—provides a stable and consistent reference. The foot remains the foundation of architectural and construction measurements in the United States, influencing everything from lumber dimensions to ceiling heights and room layouts. Because the foot is intuitively relatable to human scale, people often estimate heights, furniture sizes, and walking distances in feet. In aviation, altitude is universally measured in feet worldwide, even in countries that otherwise use metric units—an unusual but deeply embedded global convention. The foot's persistence shows how cultural inertia can remain strong even when a unit predates modern scientific measurement.
Terameter (Tm)
A terameter equals one trillion meters (10¹² m) and is used when discussing distances that exceed the scale of the solar system but do not yet reach the interstellar unit category. Large-scale solar system phenomena—such as the size of the heliosphere, the influence boundary of the Sun's magnetic field, or trajectories of far-reaching spacecraft—may be expressed in terameters. While not widely used in astronomical literature (which often prefers astronomical units, light-years, or parsecs), the terameter provides a SI-based unit that aligns cleanly with metric prefixes. It is especially useful in theoretical physics or cosmological modeling where sticking to SI units simplifies equations.