Calling an 03 number from the UK will cost the same as calling a standard landline number, which means that it is usually included in your bundled minutes if you have a contract with a mobile phone provider. If you do not have any bundled minutes, the cost of calling an 03 number will be the same as calling a standard UK landline number, which is typically around 10p to 20p per minute from a landline and 20p to 55p per minute from a mobile phone, depending on your provider and call plan. However, it’s best to check with your provider for specific pricing details as rates can vary.