How the ChargerGrade score works
A planning score built only from observable station records and geography. It is not measured uptime, a live availability prediction or a promise that a charger will work.
The 100-point formula
Every published multi-port DC fast-charging location is graded with the same seven components. We round the sum to the nearest whole point.
20 when marked available; 0 when temporarily unavailable.
3.125 points per DC fast port, capped at eight ports.
15 when the AFDC access-hours field explicitly lists 24-hour access.
3 points per other DC fast site within 10 straight-line miles, capped at five.
2.5 points per other network represented within 25 miles, capped at four.
5 for CCS and 5 for J3400/NACS as listed in the station record.
5 at ≤45 days; 3 at ≤180; 1 at ≤365; otherwise 0.
Grades
A: 85–100 · B: 70–84 · C: 55–69 · D: 40–54 · F: below 40. These bands describe resilience under our formula, not the percentage of successful charging sessions.
Why we do not publish “uptime”
The federally administered EV-ChART system collects reliability and uptime information for certain funded chargers, but station-level submissions are not released as a public national dataset. Calling our score “uptime” would overstate the evidence.
Distances and alternatives
Nearby sites are identified with a haversine calculation over latitude and longitude. The distance is straight-line distance, not route distance. A nearby record may be inaccessible due to roads, hours, compatibility or real-time conditions.
Publication threshold
Individual reports cover public operational or temporarily unavailable stations with at least two listed DC fast ports. One-port sites still participate in nearby-fallback calculations. Planned sites are excluded.
Reproducibility
Each report exposes component points, station ID, snapshot date and source. The source snapshot is retained so a score can be reconstructed even when AFDC later changes.