9V battery size and other names
A 9V alkaline battery is a rectangular block up to 48.5 mm tall, 26.5 mm wide and 17.5 mm deep (1.91 × 1.04 × 0.69 in), with both snap terminals on top. Energizer's 522 weighs about 45 g.[1 · Oct 29, 2026]
| Nominal voltage | 9.0 V[1 · Oct 29, 2026] |
|---|---|
| Height | 46.4 to 48.5 mm[1 · Oct 29, 2026] |
| Width × depth | 24.5 to 26.5 mm × 15.5 to 17.5 mm[1 · Oct 29, 2026] |
| Standard names | ANSI 1604A; IEC 6LR61 or 6LF22[1 · Oct 29, 2026] |
| Also labeled as | 522, A522, L522, MN1604, A1604[2 · Oct 29, 2026] |
| Shelf life (Energizer 522) | 5 years[1 · Oct 29, 2026] |
9V batteries in smoke alarms
- Some alarms run on a 9V; Kidde's i9050, for example, is powered by one.[3 · Oct 29, 2026] Others use AA batteries or a sealed 10-year battery, so check the label on the back of the alarm or its manual.[4 · Oct 29, 2026][5 · Oct 29, 2026]
- Kidde says off-brand or old batteries can put an alarm into low-battery mode.[4 · Oct 29, 2026]
- Replace the battery at least once a year, and right away if the alarm chirps.[5 · Oct 29, 2026][6 · Oct 29, 2026] More in the smoke alarm battery guide.
Storing and tossing 9Vs
Both terminals sit side by side on top, so a loose 9V can touch keys or coins. Energizer warns against carrying batteries loose in a pocket with coins, which can short them and make them heat up.[2 · Oct 29, 2026] For recycling, the EPA and The Battery Network suggest bagging batteries or covering the terminals with non-conductive tape.[7 · Oct 29, 2026][8 · Oct 29, 2026]
Affiliate links: if you buy through a link in this box we may earn a commission, at no extra cost to you. It does not change the sizes or sources on this page. How we handle affiliate links.
Sources: 1. Energizer 522 9V alkaline datasheet (PDF). 2. Energizer, Battery cross reference guide (PDF, 2021). 3. Kidde, i9050 battery operated smoke alarm product page. 4. Kidde, What type of battery does my alarm use?. 5. NFPA, Changing clocks and batteries. 6. Kidde, How do I replace my smoke alarm's battery?. 7. US EPA, Used household batteries. 8. The Battery Network, What to recycle. Checked Oct 29, 2026. Inch conversions are our own arithmetic from the millimeter figures. Brand names and trademarks belong to their owners; specs are restated in our own words and tables, not reproduced.