By Capacities
- SD / The second-generation Secure Digital (SDSC): ≤ 2GB
- The Secure Digital High Capacity (SDHC): >2 GB–32 GB
- The Secure Digital eXtended Capacity (SDXC): >32 GB–2 TB
- The Secure Digital Ultra Capacity (SDUC): >2 TB–128 TB
By Sizes
- Standard SD card: 32.0×24.0×2.1 mm（1.26×0.94×0.083 inch）
- Mini SD card: 21.5×20.0×1.4 mm（0.85×0.79×0.055 inch）
- Micro SD card: 15.0×11.0×1.0 mm（0.59×0.43×0.039 inch）
