A microfabricated, a nanoliter capillary viscometer includes a first channel that is defined by a first channel-defining surface in a first substrate and a second channel defining surface in a second substrate. The progress of liquid through this first channel is monitored and used to determine viscosity. Viscosities in the range of 1 cP to 1000 cP are easily measured. Self-calibrating versions of the viscometer are also disclosed.