Many "free online calculators" ask you to download a .exe or grant browser permissions. These often contain keyloggers, miners, or ransomware. The safest method is to use a reputable paid tool (DC-Unlocker costs ~$4 per code) or a trusted open-source script.
The latest security standard used in the newest Huawei mobile broadband devices. How to Calculate V4 and V5 Unlock Codes
: These calculators primarily target modems and routers. For smartphones, Huawei officially ceased providing bootloader unlock codes in 2018.