Can Wi-Fi Cause Cancer? What the Evidence Actually Says

Why do people worry about Wi-Fi and cancer?

A lot of the concern starts with the word radiation. It sounds alarming, but radiation covers a very wide part of the electromagnetic spectrum. Radio waves, visible light, ultraviolet radiation, X-rays and gamma rays are all electromagnetic radiation, but they do not interact with the body in the same way.

If someone asked me whether the word “radiation” alone was a reason to treat a home router like an X-ray source, I would say no. The type of radiation and the exposure level are what matter.

What does the current evidence say?

For ordinary Wi-Fi exposure, the current UK position is reassuring. UKHSA says there is no consistent evidence that radio signals from Wi-Fi devices adversely affect the health of the general population. It also notes that Wi-Fi signals are low power and that measured exposures are small compared with international exposure guidelines.

UKHSA’s research found that time-averaged output power from Wi-Fi devices is generally lower than from mobile phones, and normal exposure is also usually lower because a router is not normally held directly against the body during use.

Cancer Research UK gives a similarly clear consumer-facing answer: Wi-Fi and Bluetooth have not been shown to increase cancer risk. A WHO-commissioned 2024 systematic review of human observational studies also found no increased risk for several of the most extensively studied cancers from the radiofrequency exposure scenarios it assessed.

What about IARC’s “possibly carcinogenic” classification?

In 2011, the International Agency for Research on Cancer classified radiofrequency electromagnetic fields as Group 2B: possibly carcinogenic to humans. The detailed monograph was published in 2013.

That classification is often repeated in headlines without enough context. It is a hazard classification: it identifies whether something might be capable of causing cancer under some circumstances. It is not a statement that ordinary home Wi-Fi exposure has been proven to cause cancer, and it does not quantify the risk from a broadband router.

The original classification was based on limited evidence in humans, particularly evidence relating to glioma and acoustic neuroma in relation to mobile-phone exposure. It covered radiofrequency fields broadly rather than concluding that Wi-Fi routers specifically cause cancer.

Wi-Fi is not the same exposure as holding a phone to your head

Wi-Fi routers and mobile phones both use radiofrequency signals, but the exposure pattern is different. A phone used for a voice call can be held directly against the head or close to the body, while a router is normally positioned elsewhere in the room.

Radiofrequency field strength falls with distance from the source. UKHSA says public exposure from Wi-Fi is generally low relative to its recommended limits and that Wi-Fi exposures are typically lower than those from a mobile phone used for a voice call.

That distinction is useful when reading studies about “radiofrequency radiation”. A study involving heavy phone use or high experimental exposures should not automatically be presented as evidence about a router sitting several metres away in a home.

Do Wi-Fi 6, Wi-Fi 6E or Wi-Fi 7 change the health answer?

New Wi-Fi generations are mainly about better performance: more capacity, lower latency, improved efficiency and faster connections. Wi-Fi 6E and Wi-Fi 7 can also use the 6 GHz band alongside the established 2.4 GHz and 5 GHz bands.

That does not turn Wi-Fi into ionising radiation. The signals remain radiofrequency electromagnetic fields, and current public-health guidance does not identify ordinary use of newer Wi-Fi standards as a proven cancer risk.

If you are interested in the technology rather than the health question, our separate guide explains what Wi-Fi 7 is and how it affects home broadband.

What about children and Wi-Fi in schools?

Parents understandably tend to ask a stricter question when children are involved. Current UKHSA guidance does not say that standard Wi-Fi exposure in homes or schools is unsafe for children. Its Wi-Fi guidance specifically says it sees no reason why Wi-Fi should not continue to be used in the education sector.

That does not mean research should stop or that every possible radiofrequency exposure is identical. It means the evidence available to UK public-health authorities does not support treating normal school or home Wi-Fi as a demonstrated cancer hazard requiring special avoidance measures.

Do you need to change how you use Wi-Fi?

There is no evidence-based requirement to switch a normal home router off at night, buy “EMF blocking” accessories or reorganise your house to prevent cancer from Wi-Fi.

• ✓Put the router where it works well. A central, open position usually gives better coverage and avoids hiding it behind furniture.
• ✓Use Ethernet where it genuinely helps. Wired connections can be excellent for gaming, desktop PCs and home offices because of stability, not because Wi-Fi needs to be avoided for cancer prevention.
• ✓Turn it off at night only if that suits your routine. You may prefer fewer connected devices or distractions, but UK guidance does not require this as a health precaution.
• ✓Be sceptical of fear-based products. I would not spend money on a router shield or “radiation blocker” solely because an advert implies ordinary Wi-Fi is a proven cancer cause.

For the separate practical question, see our guide on whether you should turn Wi-Fi off at night.

Keep the risk in perspective

Questions about Wi-Fi can easily become detached from the size of the exposure and the strength of the evidence. For cancer prevention, established risk factors deserve much more attention than a standard broadband router.

For the wider health-and-safety question, see our guide to whether Wi-Fi is harmful.

So, can Wi-Fi cause cancer?

The important nuance is that radiofrequency fields still carry IARC’s older Group 2B “possibly carcinogenic” classification and research is continuing. That is a reason to keep following good evidence, not a reason to present a normal broadband router as an established cancer cause.

Frequently asked questions

Sources and further information