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Home › Can I swap? › SR616SW vs LR621
Can I swap?

SR616SW vs LR621: can you swap them?

1The short answer2Both ways3Differences4Buy it5Learn more
  1. 1

    The short answer

    NoSR616SW can stand in for LR621, but not the other way roundThey’re the same width and power, but SR616SW is thinner. It may wobble a little and runs out about -12% sooner. LR621 is too thick to fit where SR616SW goes.
    SR616SW+ 1.55V
    SR616SWAs thick as 2 credit cards stacked
    LR621+ 1.5V
    LR621As thick as 3 credit cards stacked
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  2. 2

    Both ways round

    Can I put LR621 where SR616SW goes?No
    Can I put SR616SW where LR621 goes?In a pinch
  3. 3

    What’s different

    SR616SWLR621
    SizeAbout as wide as a pencil eraserAbout as wide as a pencil eraser Same
    ThicknessAs thick as 2 credit cards stackedAs thick as 3 credit cards stacked
    Power1.55 volts1.5 volts
    KindWatch batteryButton battery

    Lasts longer: SR616SW (about 12% longer)

  4. 4

    Where to buy SR616SW

    As an Amazon Associate, KnowYourBatteries.com earns from qualifying purchases.

    Amazon searchEnergizer listings, any pack sizeSearch Amazon for Energizer 321
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    Amazon searchMulti-packs from any brandSearch Amazon for SR616SW multi-packs
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    Amazon searchDuracell D321 listings, the same batterySearch Amazon for Duracell D321
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  5. 5

    Learn more

    About SR616SWAbout LR621Check another pair
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Questions people ask

Can I use LR621 instead of SR616SW?

No. They’re the same width and power, but SR616SW is thinner. It may wobble a little and runs out about -12% sooner. LR621 is too thick to fit where SR616SW goes.

Can I use SR616SW instead of LR621?

In a pinch. They’re the same width and power, but SR616SW is thinner. It may wobble a little and runs out about -12% sooner. LR621 is too thick to fit where SR616SW goes.

Which one lasts longer?

SR616SW (about 12% longer).

All the numbers

SR616SWLR621
Diameter6.8 mm6.8 mm
Height1.6 mm2.1 mm
Nominal voltage1.55V1.5V
Typical capacity14.5 mAh13 mAh
ChemistrySilver oxideAlkaline
Shelf life5 yrs5 yrs
Operating temp-10 to 60 °C-10 to 60 °C
Can I use LR621 instead of SR616SW?No
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1The short answer2Both ways3Differences4Buy it5Learn more