I found myself pondering the useful range of these digital-barometer MEMS-chippies, and set about finding a pressure-altitude calculator.
This one proved useful. Can be set for units of mbar or kPa, as used in sensor specs*, and m or ft, as used for measuring altitude.
Interestingly, the altitude can also be returned in units from Planck length** to parsecs, but not in FL nor angels.
* Bosch uses hPa for some reason.
** Considerably less than 8 feet.