Parsify Desktop is not the first text calculator application out there. And while it definitely adds some unique features into the mix, it might not be the best choice for you; it's always best to decide yourself. Nevertheless, this comparison table should help you.

Element Parsify Desktop Numi Soulver 3
Price Free or €30 one-time Free or $20 one-time $34.95 after trial
Supported operating systems macOS, Windows, Linux macOS macOS
Codebase Proprietary Proprietary Proprietary
Basic units
Currency conversion ✓¹ ✓¹
Date and time operations
Custom units ✓²
Time zone operations
Import & Export
Custom themes
Plugins ✓³

¹ Feature requires purchase.

² Custom units cannot be added via user interface; coding is required.

³ ****Each plugin can only add custom units, variables, and functions. No direct access to the expression.