There are several factors that can affect the NVR storage data retention and it would be very difficult to guess how many days an NVR can record video without using the right tool.
The Bandwidth and Storage Calculator can be used as a tool to calculate frame rate, resolution and compression.
This software is free of charge and is designed for all Hanwha NVR and software products to calculate bandwidth and storage utility.
The tool can be downloaded here: https://www.hanwhasecurity.com/media/attachment/file/b/a/bandwidth_calculator_4.34.0_setup_lite.zip
There's even a feature to view a detailed report, which you can present to a client or save as reference or benchmark.