Casio · Calculators

Casio fx-350ES PLUS battery

1 × 1.5V alkaline button cell

Printed IDs: fx-350ES PLUS

How to replace it

Notes	Follow Casio user’s guide battery replacement steps for your model.

Last checked 7 October 2026

Casio fx-350ES PLUS uses 1 × LR44.

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Optional tools for opening, testing or charging — separate from the battery answer.

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Fluke 101 Digital Multimeter
Accurate open-circuit voltage and basic electrical checks
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Klein Tools MM400 Multimeter
General DC voltage checks including battery terminals
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Digital multimeter
Measure open-circuit voltage and general electronics checks
Voltage alone does not establish usable capacity, especially for rechargeables.
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Buy links are optional and separate from the battery answer.

A fresh 1 × LR44 should restore Casio fx-350ES PLUS if the battery was the problem. Work through the checks below before replacing the device.

Check the battery type
This device needs 1 × LR44 (alkaline). Rechargeable cells are not supported for this device. Same size does not always mean the same battery.
Check known model-specific issues
Primary LR44 only — no solar listed on Casio support specs
Confirm the battery itself
For most coin cells, fitting a known-good fresh cell of the correct code is simpler than capacity testing.
Still not responding?
If a correct, fresh battery installed properly does not restore the device, the fault may be elsewhere — the device may need service or replacement.

These checks follow this device’s orientation, battery type, and important notes from the maker.