Tech Tip: How Slow Is Your iPhone?
Given the recent controversy surrounding Apple’s practice of slowing down old iPhones to preserve battery life, you may be wondering if your phone was affected. Fortunately, this is easy to test with the website SlowApple.
Note: you must have low power mode turned off for this test to work properly.
On your iPhone, visit SlowApple and click the big green button. The website will run a test a javascript function test and report on how long it takes for the task to be completed. The longer it takes, the slower your phone is.
If the test reported that your phone’s speed appears to have been throttled, Apple is offering $29 batteries for the rest of 2018 (a significant discount from the regular price).
Adapted from http://www.addictivetips.com/ios/slow-iphone-check-you-device/