FAQ: Logic and Voltage Translation > Fixed DIR / DIR CNTRL Level-Shifters >> Current FAQ
Consider the worst-case values in the electrical characteristics table; VT+(max) and VT−(min) are what matters for VIH and VIL respectively. See Understanding Schmitt Trigger.
However, the VOL / VOH values into the level-shifter are most likely different than your actual worst case. They are specified for a certain output current and the actual output current will be much smaller when connected to a high-impedance CMOS input. Hence, the actual output voltages into the level-shifter will be near GND or VCC.
Note, CMOS outputs can be modeled as resistors; see [FAQ] What is the output voltage (VOH or VOL) when the output current is X or the supply voltage is Y?)