18650 vs 14500
Both 3.6 V lithium-ion. The 18650 is 18 × 65 mm against the AA-sized 14 × 50 mm 14500, with three to four times the capacity.
Last reviewed
Both are rechargeable lithium-ion cells at 3.6 volts, so electrically they behave alike. The 18650 is much larger and holds three to four times as much. They do not interchange: the 14500 is AA-sized, the 18650 considerably fatter and longer. Worth knowing that the 14500 is the one that fits an AA slot — and must never be used in one.
- Verdict:
- Same chemistry, entirely different size class
- Interchangeable:
- no
Side-by-side specifications
| Specification | 18650 | 14500 |
|---|---|---|
| Chemistry | Li-ion | Li-ion |
| Type | Cylindrical | Cylindrical |
| Nominal voltage | 3.6 V | 3.6 V |
| Diameter | 18 mm | 14 mm |
| Height | 65 mm | 50 mm |
| Typical capacity | 2000–3500 mAh | 700–1000 mAh |
| Rechargeable | Yes | Yes |
| Also sold as | INR18650, ICR18650, NCR18650 | ICR14500, IMR14500 |
Size comparison
These cells do not share a footprint, so one will not sit correctly in the other's compartment.
Size
18 × 65 mm against 14 × 50 mm. The codes give the dimensions directly, so the gap is easy to read off the label.
Capacity
2000–3500 mAh against 700–1000 mAh. The 18650 carries three to four times the energy of the smaller cell.
The AA trap belongs to the 14500
Only the 14500 shares a footprint with a household cell. An 18650 will not fit an AA compartment; a 14500 will, and at 3.6 V it should never be put in one.
The naming scheme, once and for all
Every one of these codes is its own dimensions: 18650 is 18 mm across and 65 mm long, 14500 is 14 by 50, 26650 is 26 by 65. The trailing zero is a convention rather than a measurement. Once you know that, no lithium cylindrical code needs looking up.
Same chemistry, same rules
Both are lithium-ion at 3.6 V nominal, so they charge the same way, fail the same way and need the same care. Nothing about the smaller cell makes it more forgiving — if anything the 14500 is riskier, because it fits somewhere it should not.
Which torches take which
The 14500 goes into AA-format lights, the 18650 into the thicker-bodied ones that dominate the enthusiast market. Some lights ship with a spacer allowing both. As always, the manufacturer's stated range is the authority, not the fact that a cell physically slides in.
Can I use a 14500 instead of an 18650?
Not directly. The 14500 measures 14 × 50 mm against 18 × 65 mm for the 18650, so it will not seat properly in the same compartment.
Check before you swap. Batteries with similar dimensions are not always interchangeable. Always verify voltage, chemistry and the requirements printed in your device manual before fitting a replacement.
18650 vs 14500: common questions
Is the 14500 a direct replacement for the 18650?
Both are rechargeable lithium-ion cells at 3.6 volts, so electrically they behave alike. The 18650 is much larger and holds three to four times as much. They do not interchange: the 14500 is AA-sized, the 18650 considerably fatter and longer. Worth knowing that the 14500 is the one that fits an AA slot — and must never be used in one.
What is the difference between the 18650 and the 14500?
Both 3.6 V lithium-ion. The 18650 is 18 × 65 mm against the AA-sized 14 × 50 mm 14500, with three to four times the capacity. In short: same chemistry, entirely different size class.
Are the 18650 and the 14500 the same size?
No. The 18650 is 18 × 65 mm and the 14500 is 14 × 50 mm.
Which lasts longer, the 18650 or the 14500?
The 18650. It is rated at 2000–3500 mAh against 700–1000 mAh for the 14500 — roughly 3.2× the capacity, though real runtime depends on how much current your device draws.
Background reading
The wider questions behind these two codes.