DeviceCapacity and AvailableDeviceCapacity in DeviceInformation command sent from the device to MDM is different from the capacity shown in devices settings 'About' page

The Device Information Queried from the device using MDM. The values for DeviceCapacity (Floating-point gigabytes (base-1024 gigabytes) ) and AvailableDeviceCapacity (Floating-point gigabytes (base-1024 gigabytes)) is not the same as in the device Settings --> General --> About page.

Observed in all recent iOS versions in all iOS model devices.

Response for DeviceInformation command sent to device from MDM

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "">
<plist version="1.0">

But in the device About
The capacity is 256GB and Available is 190.89 GB

Any idea on why such discrepancy exist?

This doesn’t explain all the discrepancy but the iPhone storage is calculated same as hard drive storage

1GB = 1 billion bytes, and 1TB = 1 trillion bytes; actual formatted capacity less.

i.e. 256GB = 256000000000 bytes which is in reality around 238.42 GB

I had thought the same, but still leaves a ~20Gb discrepancy.

@Annbarasi Can you share details on the MDM you are using? (including version)