Field levels and exposures

Field levels

The average magnetic field in homes in the UK is about 0.05 µT (50 nT).

What determines the field levels?

This is an average. The sort of home we live in can affect the level of fields we are exposed to. 

It’s not just where you live that matters. As you move about, you experience fields from many other sources (such as appliances) as well as the background fields in the home. This means your personal exposure is higher than the background field in the home

How do different countries compare?

The average magnetic field in a home in the UK - 0.05 μT- is lower than in many other countries and in particular lower than in the USA.

How do fields change over time?

See more detail on daily, annual and longer changes in fields over time.

Fields above various thresholds

The great majority of homes in the UK have fields less than 0.4 µT. About 1.5% of UK homes have average fields greater than 0.2 µT and about 0.4% greater than 0.4 µT. These percentages of homes with higher fields are smaller than in many other countries. More on fields greater than 0.2 and 0.4 µT

Only about a half of homes in the UK with fields above 0.4 µT get that exposure from high-voltage power lines – in the rest, the field probably comes from the distribution system or house wiring