Apple’s iPhone 11 reveal will make your current iPhone worth about 30% less Image source: Photo by Virginia Mayo/AP/Shutterstock

Now that Apple has made it official and announced the date when its iPhone 11 series of devices will be unveiled at its annual September event, it’s time for a look at the other inevitability that comes with a reveal of new versions of Apple’s most important product.

We’re referring to the effect that the upcoming September 10th iPhone 11 event (which will take place in the Steve Jobs Theater at Apple HQ) will have on the value of older iPhone models — and how much of a bite the event will take out of the trade-in value of your current iPhone.

Decluttr — a tech buyback site and refurbished seller — has revealed the results of its annual phone depreciation study which shows that handsets could lose as much as 30% of their trade-in value in the 24 hours following Apple’s event.

The full depreciation results are available here. According to the site, iPhone values tend to drop by a minimum of 40% in the first month after a new iPhone launch. After that, the value seems to stabilize while losing about 1% per month over time. Last year’s iPhone XR for example, which has a current resale price of $405, saw its trade-in value fall by 43% in the last 11 months.

Decluttr reports that this is how much resale value that recent iPhone models have lost since their launch dates:

iPhone 7 has lost 81% of its value

iPhone 8 has lost 65% of its value

iPhone 8+ has lost 61% of its value

iPhone X has lost 59% of its value

iPhone XS has lost 49% of its value

iPhone XR has lost 43% of its value

For Samsung devices, the drops are even more acute. Here are those corresponding depreciation values:

S7 has lost 91% of its value

S8 has lost 82% of its value

S8+ has lost 81% of its value

S9 has lost 77% of its value

S9+ has lost 73% of its value

S10 has lost 57% of its value

S10+ has lost 52% of its value

This is all, of course, to be expected, given how much anticipation tends to surround Apple’s iPhone event each September. One of the focuses of this year’s event will be the big improvements Apple makes to the iPhone’s camera setup, along with other exciting features that no doubt haven’t leaked yet.

These values will no doubt change in the coming weeks, but here’s a rundown of current handset trade-in values, per Decluttr: