The honest formula
Cost per charge = energy drawn × your rate. Energy drawn is a bit more than the battery gains, because AC charging loses roughly 8–12% to heat in the charger and cables — you pay for the wall side, not the battery side. That's the difference between "77 kWh pack" math and your actual bill.
Why we ask for your rate instead of guessing
Electricity prices vary several-fold by country, utility and time of day; any "average" would be wrong for most readers. Your bill's per-kWh price — or the off-peak rate if you charge overnight — takes ten seconds to find and makes every number on this page true for you. It also keeps this tool honest as prices change.
Home vs public vs gas
- Home AC: the cheap baseline; overnight off-peak plans are the EV sweet spot.
- DC fast charging: convenient, but often 2–4× home rates plus fees — fine for trips, expensive as a habit.
- Gas comparison: the second tab uses the same per-distance math for both fuels, so the savings number is apples-to-apples.
FAQ
Full charge cost?
Battery kWh × rate ÷ (1 − loss). A 77 kWh pack from empty at $0.16/kWh ≈ $13.70 with 10% losses.
Cheaper than gas?
At home rates, typically 2–3× cheaper per mile; run your numbers in the second tab.
Why more kWh drawn than added?
Charging losses — heat in the charger, cables and battery management.
Does fast charging cost more?
Almost always; plug the station's per-kWh price into the rate field to see a trip's real cost.
Where's my rate?
On your utility bill, listed per kWh; use the off-peak figure for overnight charging.