# item.guide
Side-by-Side Comparison Cylindrical Cells

21700 vs. AAA Battery

Comparing 2 standards across 4 specifications. 4 key differences identified.

Comparing:
21700
AAA Battery

A 21700 Li-ion cell measures 21.1mm in diameter and 70.4mm in length. Offering 4000 to 5000 mAh capacity at 3.6V nominal, it provides up to 50% more energy density than an 18650 cell.

View full 21700 spec sheet →

A AAA battery (IEC designation LR03, ANSI 24A) measures 10.5mm in diameter and 44.5mm in length. Alkaline AAA cells output 1.5V nominal; NiMH rechargeable AAA cells output 1.2V. Typical alkaline capacity runs roughly 800 to 1,200 mAh depending on discharge rate.

View full AAA Battery spec sheet →

Specification Comparison Table

4 Parameters
Parameter / Spec
Diameter
21.10 mm 10.50 mm
Overall Length
70.40 mm 44.50 mm
Nominal Capacity
4000–5000 mAh
Alkaline Voltage
1.50 V