New iPhone 18 battery draining quickly

Yes, some extra battery drain can be normal during the first few days with a new iPhone. The phone may still be syncing iCloud, indexing photos, restoring apps, and completing background setup.

Check Settings > Battery to see what is consuming the most power. Also install the latest iOS update, restart the phone, and check whether Photos or iCloud is still syncing.

If the battery is still draining quickly after about a week with light use, contact Apple Support and ask them to run a battery diagnostic.

You may also find this NexPloreInfo guide useful: iPhone 18 Pro Review, Price & Specs:

[Edited by Moderator]

See especially “If battery life is less than expected after an update“ here. You did just perform a major update.

If the battery in your iPhone or iPad drains too quickly - Apple Support

Maybe you have an 80% or 90% charge limit? Take the limit off.

iphones burn probably 40-50% battery in a day without any "use" by you.