Buying guide· Consumer Electronics
Noise-cancelling headphones: what the specs mean
How active noise cancelling works, over-ear versus earbuds, battery figures, multipoint and codecs — what to compare before you buy.
- HotWhatHow editorial team
- Last reviewed
- 4 min read
Noise-cancelling headphones use microphones and processing to reduce steady background sound such as engine hum, air conditioning and train rumble. They are popular for commuting, travel and working in busy spaces. This guide explains what the specifications on the box mean, how to compare models sensibly and what to check before you buy. It covers both over-ear headphones and in-ear earbuds.
How active noise cancelling works
Small microphones pick up sound around you, and the headphones produce an opposite sound wave that cancels part of it. Active noise cancelling (ANC) is most effective on low, constant sounds; it is less effective on sudden or higher-pitched sounds such as voices or clattering. The physical seal — the ear cushions or ear tips — blocks higher frequencies, so fit matters as much as the electronics.
Manufacturers rarely publish a standard noise-reduction figure, and when they do it is not measured in the same way across brands. Independent measurements and reviews from publications that test headphones are the best way to compare cancelling strength.
Over-ear or in-ear?
Over-ear
Large cushions surround the ear, which helps with passive isolation and comfort on long journeys. They usually have bigger batteries. They are bulkier to carry and can feel warm.
In-ear (earbuds)
Small and easy to carry, with a charging case that tops up the battery on the move. The seal depends on the ear tips, so trying different tip sizes matters. Battery life per charge is shorter than most over-ear models, but the case extends it.
Battery life and charging
Battery figures are usually quoted with ANC on and off, at a moderate volume. Look for the ANC-on figure, since that is how most people use them. For earbuds, check both the earbud battery life and the total including the case. Quick-charge features, which give a few hours of playback from a short charge, are useful for travel. USB-C charging and, for some earbuds, wireless charging are conveniences worth checking.
Connectivity and codecs
- Bluetooth version. Newer versions can improve connection stability and efficiency, but range and reliability also depend on design.
- Multipoint. Lets the headphones connect to two devices at once, such as a laptop and a phone, and switch between them.
- Codecs. The format used to send audio over Bluetooth. SBC and AAC are widely supported; some headphones support higher-bitrate codecs such as LDAC or aptX variants, but your phone must support the same codec for it to make any difference.
- Wired option. Some over-ear models have a 3.5 mm or USB-C wired mode, useful for in-flight entertainment.
Calls, controls and comfort
Look at the number of microphones and any wind-noise reduction if you take calls outdoors. Touch controls can be accidentally triggered; physical buttons are easier to use with gloves. Transparency or ambient mode lets outside sound in, which is useful when crossing roads or listening for announcements. Weight, clamping force and cushion material affect long-term comfort. If you wear glasses, the cushions matter even more.
Key specs explained
| Spec | What it tells you | What to look for |
|---|---|---|
| ANC | Active noise cancelling present, sometimes adjustable | Independent measurements for cancelling strength |
| Battery life (hours) | Playback time, ANC on and off | The ANC-on figure; for earbuds, the total with the case |
| Quick charge | Playback from a short charge | Useful if you often forget to charge |
| Bluetooth version | Wireless standard | A recent version, though design matters too |
| Multipoint | Connects to two devices at once | Yes, if you switch between phone and laptop |
| Codecs | SBC, AAC, LDAC, aptX | Codecs your phone also supports |
| Weight (g) | Comfort on long wear | Lighter for long journeys; check clamping force |
| Water resistance (IP) | Protection against sweat and rain | An IP rating if you exercise or commute in the rain |
Questions to ask before you buy
- Will I mostly use them on public transport, on flights, at a desk or for exercise?
- Do I prefer over-ear comfort or the portability of earbuds?
- What is the battery life with ANC switched on?
- Do I need multipoint to switch between a phone and a laptop?
- Does my phone support the codecs listed?
- Can I return them if the fit or comfort is not right for me?
Frequently asked questions
Do noise-cancelling headphones block all sound?
No. They are most effective on low, steady sounds. Voices and sudden noises are reduced mainly by the seal of the cushions or ear tips, not removed completely.
Is a higher-bitrate codec worth it?
Only if your phone supports the same codec and you listen to high-quality sources. For many listeners, fit and the headphones' tuning make a bigger difference.
Can I use noise-cancelling headphones on a plane?
Most people can, and ANC is well suited to engine noise. For the in-flight entertainment system, you may need a wired connection or a Bluetooth adapter, so check whether the headphones have a wired option.
Are earbuds or over-ear headphones better for calls?
It depends on microphone design rather than form factor. Check the number of microphones and any wind-noise reduction, and read independent call-quality tests if calls are important to you.
Prices & links
HotWhatHow compares live prices from retailers as they are connected to the site. When offers are available, we rank them by the total landed price — the item price plus standard delivery — and show when each price was last checked. Some retailer links are affiliate links; we may earn a commission, which never changes which offer we label as the cheapest. This guide is based on manufacturer specifications and general product information, not on our own use of the products.
Written by the HotWhatHow editorial team with AI assistance, from manufacturer specifications and general product information. We do not test products ourselves, invent ratings or quote prices in guides.