LR521 specifications
Typical applications
- Toys
- calculators
- small lights
- simple electronics
Replacement decision
Resolve the original marking to this profile, then confirm nominal voltage, chemistry, dimensions, polarity and any drain or terminal suffix. Capacity alone does not establish interchangeability.
Equivalence and fit table
These rows use the catalog’s source-backed profile data and compatibility rules. An exact alias resolves to the same profile; every other row is a comparison to review, not an automatic substitute.
| Marking | Catalog profile | Voltage | Chemistry | Dimensions | Fit decision |
|---|---|---|---|---|---|
| LR521 / AG0 | LR521 · Alkaline | 1.5 V | Alkaline manganese dioxide | 5.8 × 2.1 mm | Exact catalog match Resolves to LR521; confirm polarity and the device marking. |
| 379 | 379 · Silver oxide | 1.55 V | Silver oxide | 5.8 × 2.15 mm | Same diameter · different height Use the specified height; do not rely on contact spring travel. |
| LR516 | LR516 · Alkaline | 1.5 V | Alkaline manganese dioxide | 5.8 × 1.6 mm | Same diameter · different height Use the specified height; do not rely on contact spring travel. |
Fit guidance for LR521
The catalog resolves LR521 and AG0 to the LR521 profile. Reviewed comparison rows are 379: same diameter · different height, LR516: same diameter · different height. Use the Fit decision column and the device manual before selecting a non-exact row.
Verify before replacing LR521
- Read the complete marking and check whether it resolves to LR521 or to another profile.
- Compare the 1.5 V, Alkaline manganese dioxide, and 5.8 × 2.1 mm values shown above with the device manual.
- For a non-exact row, follow its generated fit decision and confirm polarity, terminals, drain behavior, or charging requirements before installation.
Related reading: Silver oxide vs alkaline button cells · How to read a button-cell code · How to measure a battery safely
Reviewed comparisons
Technical sources
- International Electrotechnical Commission — IEC 60086-1:2026 — Primary batteries, general requirements
Primary-battery nomenclature, form, fit, function, terminal and electrochemical-system framework.
- Energizer — Battery Replacement Guide
Cross-reference codes and manufacturer guidance to replace the same size and type together.
- Duracell — Battery Cross Reference Chart
Independent manufacturer cross-reference families and corresponding product numbers.
- Duracell — Battery chemistry technical bulletins
Alkaline, lithium-manganese-dioxide, zinc-air and silver-oxide chemistry behavior.