How much does it cost to replace the battery in a iPhone 12 Pro max

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iPhone Battery Replacement - Official Apple Support

What country? It's $69 plus tax if done by Apple in the United States. There are additional shipping charges if it has to be sent out for whatever reason. Apple Authorized Service Providers are free to set their own prices although they tend to be competitive with Apple. Prices in other countries vary. The other issue is that in some countries Apple reduces all services to complete replacement, although it may be at an equivalent price.