Wh/km
Electric efficiency as watt-hours per kilometer, the fine-grained unit some trip computers and spec sheets use. Lower is better.
Wh/km measures electric consumption in watt-hours per single kilometer. It carries exactly the same information as kWh/100 km, just at a finer grain: divide a Wh/km value by 10 and you have kWh/100 km, so 160 Wh/km and 16.0 kWh/100 km are one number in two outfits.
You will meet Wh/km on some trip computers and in spec databases. Its precision makes it the unit CarPairly stores internally. The WLTP and EPA efficiency figures are stored as separate Wh/km values, one per test cycle. kWh/100 km, kWh/100 mi, and mi/kWh are derived from the stored value for the relevant cycle using fixed formulas, never entered separately.
As with every consumption figure, lower is better, official values come from a named test cycle, and your own trip computer can read higher in winter and at speed.