Ontario EV charging cost: TOU vs ULO vs tiered

Compare Ontario electricity plans for your household and electric vehicle together. Start with household use that excludes the EV. The calculator then adds the same charging demand to each plan, so a low charging price does not hide a higher cost for the rest of the home.

Enter household kWh in the eight time windows shown, or use supported dated meter records. Keep the period, local time zone and season consistent. Each household kWh should appear once. Do not include existing EV charging in the household amounts if you are adding it again here.

For a manual estimate, add annual driving, vehicle energy use and charging losses. Choose one charging window or split charging across the listed windows. The split describes when you expect to charge; it does not schedule your charger. An imported file instead uses the separately metered EV charging in its ev_kWh column.

Check a file before relying on an imported comparison. The upload needs the supported columns, units and a complete supported calendar month. Use the meter service time zone and the first-tier allowance confirmed for those dates. For manual totals, use the displayed season and the same monthly household use for every plan. Enter zero explicitly in windows with no use.

Monthly EV energy = annual km × kWh/100 km ÷ 100 ÷ (1 − charging losses) ÷ 12. Allocate it to the entered price windows. TOU and ULO use the same eight household windows. Tiered charging is tiered(household + EV) minus tiered(household), rather than treating EV energy as a new first block. Compare both incremental charging and whole-house cost.

Compare both result totals. The extra charging cost is the difference made by adding the EV. The combined household result includes the home and charging together. The plan with the lowest extra charging cost may not have the lowest combined cost.

These illustrative inputs are separate from your saved answers. Prices, use and performance are held constant for this worked scenario; they are not personal defaults.

This worked example uses the dated OEB snapshot shown in its rate inputs.

Household use excludes the EV. Cheapest charging alone can differ from the cheapest combined household plan. Published rate period is fixed; exact calendar billing needs interval data.

Imported records are processed on your device. The saved estimate retains source metadata and validated totals. Unknown dates, missing intervals, unsupported formats or units stop the import; missing data is never filled in.

Use the charging-loss field only for losses that are not already included in your vehicle energy figure. Check the source of that figure before adding losses. Annual driving is spread over twelve months; actual monthly travel can vary.

Check the utility-confirmed first-tier allowance for the month. Household use can already fill part or all of that block before the EV is added. Money is rounded for display, while the calculation keeps unrounded values.

The Ontario comparison covers the Electricity line and Global Adjustment. It excludes delivery, regulatory charges, tax and rebates, so it is not a complete bill forecast. Published prices have a stated period and checked date.

Use personal prices that match the billing month when the stored prices do not fit your scenario. Follow the local time windows shown for TOU and ULO. TOU means time-of-use pricing; ULO is the ultra-low overnight plan. Your utility can confirm the relevant allowance and plan details.

Use a qualified local electrician for home charging equipment. The calculator does not check your home supply, wiring, charger rating or safe installation.

Ask your utility or an energy adviser to review unclear bill periods, time windows or tier allowances. Bring your meter records, current tariff and charging plan. Keep the saved inputs so they can see exactly what the comparison assumes.