Open a packet of hearing aid batteries and you will find a row of tiny silver discs and a colour on the packaging. The numbers and colours are not random. They are a long-running shorthand that lets everyone, from manufacturers to pharmacy shelves, talk about the same battery. This article explains what the sizes and colour codes mean and how rechargeable hearing aids fit into the picture, written as general information rather than advice about any particular device.
What Is Inside a Disposable Hearing Aid Battery
Most disposable hearing aid batteries are zinc-air cells. Air entering through small holes in the casing reacts with the zinc to produce power. To keep that reaction from starting too early, each battery is sealed with a coloured foil tab, and once the tab is removed the battery begins to discharge. That is why the tab is only taken off when a battery is about to be used.
These cells are small, light and give a steady output, which suits devices that sit in or behind the ear.
The Four Common Sizes
Four sizes cover most disposable hearing aid batteries: 10, 312, 13 and 675. Each has a colour that is printed on the packaging and the tab. The table uses dimensions published by battery manufacturers; exact figures can differ slightly between makers.
| Size | Colour code | Approx. size (diameter x height) | Commonly used in |
|------|-------------|-----------------------------------|------------------|
| 10 | Yellow | 5.8 x 3.6 mm | Very small devices, such as completely-in-canal styles |
| 312 | Brown | 7.9 x 3.6 mm | In-the-ear and some behind-the-ear styles |
| 13 | Orange | 7.9 x 5.4 mm | Behind-the-ear and some in-the-ear styles |
| 675 | Blue | 11.6 x 5.4 mm | Larger, higher-power behind-the-ear styles |
The pattern is simple: smaller numbers generally sit in smaller devices, and the largest, size 675, belongs to the larger behind-the-ear designs. Which size a particular hearing aid takes is set by the device itself, and the manufacturer's manual states it. The sizes are not interchangeable.
Why the Colour Codes Exist
The colour code is there to cut down on confusion. The numbers are small and the batteries are smaller still, so a bright, consistent colour makes it easy to match a packet to a device. The colour is shown on the pack and on the tab, and the same colours are used by most common brands.
A word on the numbers themselves: sizes 10, 312 and 13 are not a ladder from small to large. Size 312 and size 13 share the same diameter and differ in height, which is part of why the number alone can be confusing and the colour helps.
Where Rechargeable Hearing Aids Fit In
Some hearing aids are rechargeable instead of using a disposable battery. In place of a changeable zinc-air cell, they contain a built-in rechargeable cell, and the device sits in a charging case or charger when it is not in use. Our hearing aid solutions hub describes the two options, disposable zinc-air batteries that are activated by air and rechargeable devices that charge in a case.
A few general points tend to come up:
- Rechargeable models generally do not take the numbered batteries above, so there is no size or colour code to match.
- Charging cases and chargers are part of the device system and are specific to each manufacturer and model.
- Some devices offer a choice of rechargeable or disposable-battery versions within the same style, and the product information for that model sets out which options exist.
How the Choice Gets Made
Whether a device takes disposable or rechargeable power is part of its design, and it often comes up alongside other features such as size and style. Our explainers on hearing aid styles and what is new with modern hearing aids cover those other pieces, and the general upkeep side is in caring for your hearing aids.
A Quick Summary
- Most disposable hearing aid batteries are zinc-air cells sealed with a coloured tab.
- The four common sizes are 10 (yellow), 312 (brown), 13 (orange) and 675 (blue).
- The colour code makes matching a pack to a device easier, and the sizes are not interchangeable.
- Rechargeable hearing aids use a built-in cell and a charger rather than the numbered batteries.
If you'd like to chat about your hearing, the friendly team at CQ Audiology in Rockhampton is here to help. You can read about hearing aids in Rockhampton, call (07) 4848 6528 or book online.
This article is general information, not personal medical advice. For advice about your own hearing, speak with your GP or a hearing care provider.
Sources: battery manufacturer product information (sizes, colours, dimensions and zinc-air tab); hearing aid manufacturer product information (battery type for each model).
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