FuelInfo
The FuelInfo mod provides extended information about standard Minecraft furnaces (including their variants) and brewing stands. Now you can easily find out how many items can be smelted, how much time remains until the process is completed, and how many potions can be brewed.
To use the mod, simply hover your cursor over the progress arrows, flame icons, and fuel indicators:

Additional feature: hold the Shift key while hovering the cursor to switch the way information is displayed.
Compatibility
The mod is available for NeoForge and Fabric versions of Minecraft.