Open-E - Calculate how much space will be available in a specific RAID configuration with your Open-E DSS V7 or DSS V7 SOHO data storage software thanks to the new Storage License
Synology: Online RAID Calculator Tool – Marius Hosting
RAID Calculator APK for Android Download
Raid Calculator - Apps on Google Play
How can 2TB drive give protection for 12TB of data in a SHR (Synology Hybrid RAID)? - Server Fault