The average magnetic field strength at the Sun’s surface is about 1 Gauss.
A gauss is a unit used to measure magnetic-field strength; 1 gauss equals 10⁻⁴ tesla. The Sun’s average surface field is relatively modest compared with its concentrated magnetic regions. Sunspots, for example, can have fields measuring thousands of gauss, making them far stronger than the surrounding quiet surface.
The Sun’s magnetic field is generated by the movement of electrically conducting plasma, especially in and around its convection zone. Because the Sun is gaseous rather than solid, different latitudes rotate at different speeds. This differential rotation stretches and twists magnetic field lines, helping drive the approximately 11-year solar activity cycle.
The field is not uniform: its strength changes with location and time. Magnetic fields organize prominences, coronal loops, flares, and coronal mass ejections. They also guide charged particles into the solar wind. Thus, 1 gauss is an average figure, not the field strength of every point on the solar surface.