During an HV Check, an estimate of the battery capacity is also shown on screen.
All models (except Prius Plus and Prius Plugin) have a nominal 6.5 Ah battery capacity.
To evaluate capacity follow these guidelines:
1) be sure to have at least 60% SOC, engine and battery at operating temperatures (i.e. not too low or too high)
2) park the car
3) start A/C at the lowest temperature, to put some load on the battery
4) be sure the petrol engine is not running and have completed S1 phase
4) start HV Check
5) keep the check running until actual SOC is at least 10% less than the starting SOC
The Estimated Capacity will change color when enough data will be collected.
The same information is present on the report from Hybrid Reporter