How this index was compiled

Byrvia is a lookup for people who have a dead cell in one hand and a code written on it. The page should answer, in order: what the code means, what voltage and size it is, which other codes are the same cell, and which similar codes are not.

Electrical numbers are taken from manufacturer documents read for this build on 29 October 2026. The set is Energizer product datasheets, Energizer's battery cross-reference guide and the alkaline, silver-oxide and zinc-air manuals, Panasonic's September 2022 coin-lithium lineup, and Renata's consumer scope of supply, part ZW9843, version 07.2016. A source URL is stored on every cell. Where a PDF path returned 404, the number that used to be indexed from it was left out.

Capacity is published as the brand printed it, with the load and cutoff when the sheet states them. Energizer's CR2032 is 235 mAh to 2.0 V on 15 kΩ at 21°C. Panasonic's CR2032 is 225 mAh. Those are both kept. They are not averaged. If a sheet did not state a milliamp-hour or a dimension, the field says "varies by brand" and the gap is listed in DATA_GAPS.md in the project files.

Equivalence is taken from a chart that names both codes, or from the designation line of a datasheet. Energizer's A76 product page lists AG13, and also lists 357 and SR44. The page records that list and then says what the alkaline handbook says about using an alkaline cell where a silver-oxide cell was specified. Fit and chemistry are written as separate claims.

The drawings are generated by the build script from the same millimetres shown in each table. Round cells get a top view and a side view at one scale; the 9 V, CR-P2 and 2CR5 get the rectangle the Energizer drawing says they fit inside. Terminal steps, seals and markings are not drawn, because the sources do not give their sizes. Where a dimension is missing, as for CR2, there is no drawing. The true-size outlines use CSS millimetres, which depend on the screen; the calibration control corrects that, and printing at 100% uses paper millimetres.

The compare verdicts come from fixed rules over those figures, listed on the compare page. They lean towards "do not swap". Device lists come only from the device column of Energizer's cross-reference guide.

Car-brand key-fob tables are not included. The assignment changes by model year, and no official manual was used to build one. The key-fob page tells you to read the cell in the fob.

Corrections are welcome at hello@byrvia.com. Name the code, the figure you think is wrong, and the datasheet. Byrvia FZE publishes the site.