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Home › Batteries › LR721
Button battery

LR721 battery

1What it is2Safety3Other names4Tip5Facts6Buy it
  1. 1

    What it is

    LR721+ 1.5V

    LR721 is a button battery, about as wide as a pea. It gives 1.5 volts.

    Search Amazon for LR721As an Amazon Associate, KnowYourBatteries.com earns from qualifying purchases.

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  2. 2

    Safety first

    Keep away from children and pets

    A swallowed coin or button battery can cause serious burns inside the body within 2 hours. If you think one was swallowed, get emergency help right away.

    Swallowed one? What to do now →
  3. 3

    Names you might see in the store

    All of these are the same battery. Any of them will work.

    AG11162LR58
  4. 4

    A tip before you buy

    SR721SW is the same size and lasts longer

    It costs a little more but gives steadier power. Worth it for cameras, measuring tools and watches. For toys and laser pointers, LR721 is fine.

    About SR721SWCompare the two
  5. 5

    Quick facts

    Size
    About as wide as a pea
    Thickness
    As thick as 3 credit cards stacked
    Power
    1.5 volts
    Keeps in a drawer for
    About 5 years
    Rechargeable?
    No, use once
    Found in things like
    Analog watchesCalculatorsSmall remotes
  6. 6

    Where to buy it

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

    Amazon searchEnergizer listings, any pack sizeSearch Amazon for Energizer 162
    See results on Amazon →
    Amazon searchMulti-packs from any brandSearch Amazon for LR721 multi-packs
    See results on Amazon →
    Amazon searchDuracell listings, the same batterySearch Amazon for Duracell LR721
    See results on Amazon →

    Buttons open amazon.com 🇺🇸, picked from your country.

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See it at real size

LR721 next to a US quarter and an AA battery. “Real size” matches your hand once your screen is set up in Measure it.

LR721Thickness 2.1US quarterAA

What do the letters mean?

Battery names are a code. Here’s how to read LR721:

LAlkaline chemistry (1.5V)
RRound coin / button form factor
7≈ 7 mm diameter (exact 7.9 mm, 0.311 in)
212.1 mm thickness (exact 2.1 mm, 0.083 in)

The same battery from each brand

BrandTheir name for it
Official nameLR721
Energizer162

Exact measurements

Width
7.9 mm (0.311 in)
Thickness
2.1 mm
Voltage
1.5V (empty at 0.9V)
Energy stored
18 mAh
Weight
—
Made with
Alkaline
Works between
-10 … 60 °C
Official code
LR721

Questions people ask

Is LR721 the same as AG11?

Yes. They’re the same battery with different names. You might also see AG11, 162, LR58.

Can I use SR721SW instead?

Yes, and it’s even better. Same size, but it lasts longer and gives steadier power.

How long will a spare keep in a drawer?

About 5 years if it stays cool and dry.

Can I recharge it?

No. Never try to recharge it.

Which way up does it go?

Usually with the side marked “+” facing you or facing up. Look at how the old one sits before you take it out.

LR721+ 1.5V
LR721Button battery
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1What it is2Safety3Other names4Tip5Facts6Buy it