The earth's magnetic field lines resemble that of a dipole at the centre of the earth. If the magnetic moment of this dipole is close to $$8 \times 10^{22}$$ Am$$^2$$, the value of earth's magnetic field near the equator is close to (radius of the earth = $$6.4 \times 10^6$$ m)

The magnetic field at a distance $$R$$ on the equatorial line of a short dipole is given by:

$$B_{eq} = \frac{\mu_0}{4\pi} \frac{M}{R^3}$$

$$B_{eq} = 10^{-7} \times \frac{8 \times 10^{22}}{(6.4 \times 10^6)^3}$$

$$B_{eq} \approx 0.0305 \times 10^{-3}\text{ T} = 3.05 \times 10^{-5}\text{ T}$$

$$B_{eq} = 3.05 \times 10^{-5} \times 10^4\text{ Gauss}$$ ($$1\text{ Tesla} = 10^4\text{ Gauss}$$)

$$B_{eq} \approx 0.305\text{ Gauss} \approx 0.32\text{ Gauss}$$