Coin & Button Batteries — Finding the Right Size for Fobs, Trackers & Remotes
Last verified: October 2026
A calm, no-jargon way to read the code on a coin cell and match the exact size for your key fob, remote, or tracker. Rather have a second pair of eyes? My number is (330) 200-8042.
Reading a Coin-Cell Code, at a Glance
A dead key fob or quiet tracker stops being a puzzle once you can read the code stamped on the battery. This guide walks you through codes like CR2032, CR2025, CR2016, CR1632, and LR44 in plain English — what each part of the code means, where each size is used, how to match the exact one, and why some coated cells fail in trackers. There's a printable 29-page version up top.
Common Questions
1 What does a code like CR2032 mean?
Read it in three pieces. The letters are the chemistry (CR is lithium, LR is alkaline); the first two numbers are the width across in millimeters (20 mm); and the last two are the thickness in tenths of a millimeter (3.2 mm). So CR2032 is a 20 mm wide, 3.2 mm thick lithium cell.
2 Can I use a CR2025 instead of a CR2032?
Better not to. They're the same width but the 2025 is thinner, so it can sit loose, lose contact, and hold a little less charge. Match the exact code — all four numbers — for a reliable fit.
3 Where do I find the code on my fob or remote?
It's printed on the flat side of the old cell. Use your phone camera to zoom in on the tiny print. If it's worn off, the size is often printed inside the battery compartment or in the gadget's manual.
4 I put a new CR2032 in my tracker and nothing happened — why?
Often a bitter child-safety coating on the cell gets between it and the contacts in a very low-power gadget like an item tracker. Try an uncoated CR2032 of the same size, and store it extra carefully away from children.
5 Are dead coin batteries safe to toss in the trash?
Treat them as dangerous. A used coin cell can still burn a child if swallowed, so tape over each one, keep them out of reach, and take them to a battery-recycling drop-off or follow your local rules. See our button-battery safety guide.
Would You Rather I Just Help?
Reading a coin-cell code and fitting the right battery is one of my favorite quick jobs — it gets a quiet fob, remote, or tracker working again in minutes. Bring me the gadget or the old cell and I'll read the size, fit the right one the right way round, and show you how to store the spares safely. $99 flat for a visit, 30-day come-back-free, nothing to sell you.
Would you rather I just do this for you?
No shame in it — plenty of folks would rather hand it off, and that's what I'm here for. I'll come to your home, set it up right, and make sure it's working before I leave. Flat $99 per visit — no jargon, no upsell, and every visit is 30-day come-back-free.
Not a hardware job? I can often fix it remotely for $49 — a secure screen-share, up to 2 hours, that you watch the whole time and can end whenever (included free for $39/mo Support Plan members, and it counts toward the $99 if it turns out I need to come out).