1. Standard SIM card (Mini-SIM) Size: 25mm × 15mm
2. Micro-SIM card Size: 15mm × 12mm
Device used: iPhone 4/4s, some old Android models (such as Samsung Galaxy S3/S4), etc.
How to distinguish: Larger than Nano-SIM, but smaller than standard SIM. The plastic frame is narrower, but there is still a clear frame.
3. Nano-SIM card Size: 12.3mm × 8.8mm
Devices used: iPhone 5 and later, modern Android flagships (such as Samsung Galaxy S10 and later).
How to distinguish: Smaller than Micro-SIM, the metal chip occupies most of the card area. Some Nano-SIMs may have a notch on the back (depending on the manufacturer's design).
