SR44 vs LR44 is a chemistry decision, not a size decision. Both cells fit the same approximately 11.6 × 5.4 mm envelope, but SR44 is a 1.55 V silver-oxide cell while LR44 is a 1.5 V alkaline cell. A device may power up with either and still deliver different accuracy, runtime or end-of-life behavior.
SR44 and LR44 comparison
| Specification | SR44 / Energizer 357-303 example | LR44 / Energizer A76 example |
|---|---|---|
| Chemistry | Silver oxide, Zn/Ag2O | Alkaline manganese dioxide, MnO2 |
| Nominal voltage | 1.55 V | 1.5 V |
| Approximate size | 11.6 mm diameter × 5.4 mm height | 11.6 mm diameter × 5.4 mm height |
| Published typical capacity | 150 mAh to 1.2 V under 6.8 kΩ at 21 °C | 150 mAh to 0.9 V under 7.5 kΩ at 21 °C |
| Selection priority | Stable-voltage, threshold-sensitive or manufacturer-specified silver-oxide service | Equipment designed around alkaline discharge behavior and cost |
The numbers above come from Energizer’s official 357/303 SR44 datasheet and A76 LR44 datasheet. They are useful because the manufacturer publishes the test conditions, not just the marketing capacity.
The 150 mAh comparison trap
Both cited datasheets show 150 mAh. That does not make the cells equivalent. The SR44 value is measured to a 1.2 V cutoff with a 6.8 kΩ load. The LR44 value is measured to a lower 0.9 V cutoff with a 7.5 kΩ load. Temperature is the same, but the load and endpoint are not.
Capacity is the charge delivered between a defined start and cutoff under a defined load. Lowering the cutoff lets a test count energy that a threshold-sensitive device may never use. A meter that stops operating at 1.2 V cannot benefit from capacity measured down to 0.9 V. Procurement teams should therefore compare discharge curves at the device’s actual load and minimum voltage, not copy two headline mAh values into a bid sheet.
This test-condition check applies beyond LR44 and SR44. The coin cell selection guide explains how chemistry, cutoff and load interact across a wider range of button cells.
When the chemistry difference changes device behavior
Silver-oxide cells are commonly selected where a stable operating voltage matters. Examples include calibrated measuring tools, cameras, watches and other circuits whose reading or timing depends on supply voltage. An alkaline cell can be appropriate where the equipment was designed around its voltage decline and where procurement cost has more weight than a flat discharge profile.
This is a design rule, not a promise that every SR44 will outperform every LR44 in every product. Actual behavior depends on load, temperature, cutoff, storage history and supplier. Energizer lists watches, toys, glucose monitors and calculators among A76 applications on its official LR44/A76 page, showing why the equipment specification still governs.
Can SR44 and LR44 be substituted?
Physical fit is usually not the obstacle. The main questions are the permitted voltage range and the device’s end-of-life threshold. A substitution is lower risk only when the equipment maker permits both chemistries or the designer has tested both across the complete operating window.
Do not approve a substitution from a retailer’s cross-reference alone. Product pages often group LR44, A76, AG13, 357 and SR44 because they fit the same compartment. Some of those labels identify different chemistries. The cross-reference helps locate a size; it does not rewrite the discharge curve.
| Device condition | Recommended decision | Reason |
|---|---|---|
| Manual explicitly requires SR44 or silver oxide | Use the specified silver-oxide cell | The circuit may depend on the voltage profile |
| Calibrated instrument or legacy camera/meter | Validate SR44 first; do not cost-substitute blindly | Supply-voltage drift can affect operation before the cell is empty |
| Manual lists LR44/A76 alkaline | Use the approved LR44 chemistry unless engineering releases an alternative | The product was qualified around alkaline behavior |
| New OEM design | Test both only if both will be approved sources | Qualification should cover pulse, cutoff, temperature and storage |
How to qualify an alternative cell
- Confirm the IEC designation, chemistry and exact dimensions on the datasheet.
- Measure operating voltage at the device’s normal and peak loads.
- Set the endurance-test endpoint to the device’s real minimum voltage.
- Test at the coldest and hottest specified device temperatures.
- Check readings, timing, alarms or motor behavior throughout discharge.
- Inspect the holder contact pressure and polarity protection.
- Record the approved manufacturer and model rather than the size alias alone.
JBWCELL supplies separate silver-oxide button cell and 1.5 V alkaline AG/LR ranges. Keeping the two categories separate in the bill of materials prevents a warehouse-level size match from becoming an unreviewed chemistry change.
Dimensions and names still need checking
Even when the nominal envelope is the same, review the manufacturer drawing for maximum height, diameter, gasket profile and terminal face. A tight compartment or marginal spring contact can turn a paper-compatible cell into an intermittent connection. For nearby formats and code interpretation, use the button cell sizes chart, then return to the exact datasheet before release.
Control the approved cell in purchasing and inspection
Once testing is complete, record the chemistry, manufacturer and exact model in the approved bill of materials. The incoming-inspection plan should verify the label, dimensions, open-circuit voltage and supplier paperwork against that released source. If purchasing proposes a different alias, factory or chemistry, route it through component change control and repeat the tests that are sensitive to voltage profile. Keep qualification samples and test reports tied to the production lot. This prevents an apparently equivalent 11.6 mm cell from entering production through a warehouse cross-reference that engineering never reviewed.
Frequently asked questions
Is SR44 the same as LR44?
No. They commonly share the same physical envelope, but SR44 is a 1.55 V silver-oxide chemistry and LR44 is a 1.5 V alkaline chemistry. Their voltage behavior and published capacity test conditions differ.
Can I replace LR44 with SR44?
Only when the device manufacturer permits it or engineering testing confirms the device tolerates the voltage profile across load and temperature. Physical fit alone is not sufficient approval.
Why do SR44 and LR44 datasheets both show 150 mAh?
In the cited Energizer examples, the values were measured with different loads and different cutoff voltages. The SR44 test ends at 1.2 V; the LR44 test continues to 0.9 V. Those headline numbers are not a controlled apples-to-apples capacity comparison.
Specify chemistry in the RFQ
Send the device type, required chemistry, normal and peak load, minimum operating voltage, temperature range, compartment dimensions, termination and annual volume. JBWCELL’s enquiry channel can then quote an SR44 or LR44 configuration against the actual operating requirement rather than an ambiguous size alias.
