West Ham's capacity at their new ground has a complicated history. It can be configured to have a capacity of up to 67,000 but the lease, or agreement is set at 62,500. Here's an explanation from West Ham
https://www.whufc.com/news/articles...ed-granted-permission-london-stadium-capacity
I believe City's record attendance at the Etihad was 54,603 against Leicester City in 2016. And you will find references online to a capacity of 55k. Since then we took out 3 rows of seats at the front of the ground to facilitate large advertising hoardings. The North Stand expansion may have also temporarily reduced some capacity at the back of the 2nd tier. In 2023/24, before work on the North Stand started we averaged 53,346. When we applied for planning permission for the new stand, the documentation described the capacity as "54,048 following the expansion of the South Stand in 2014".
This season some websites give our average attendance to be 52,847. In February 2025 we played Liverpool at the Etihad and the official attendance was 52,803. There would have been some empty seats due to segregation and there would have been some loss of seats due to work on the North Stand.
The covering letter put before MCC for the North Stand expansion said, "The expansion of the Etihad Stadium North Stand to provide an additional net capacity of 7,910 and an increase in the overall stadium capacity of up to 61,958".
Note pre works capacity of 54,048 + 7,910 results in 61,958.