Some older calculators used reverse-engineered firmware algorithms to generate codes locally on a PC or phone.
Most "calculators" are software tools that use your device’s IMEI number huawei unlock code calculator 16 digit
Check if your phone has a "SIM lock" screen when inserting a foreign SIM. If it just boots normally without asking for a code – your phone is already unlocked, or it uses the new OTA method. huawei unlock code calculator 16 digit