Disclaimer, data sources & privacy

Estimates, not advice

WhenToCharge estimates what a home EV charging session would cost at different start times. The results are for general information only and are not financial, legal, or electrical advice.

The calculator assumes a constant charging rate and 90% wall-to-battery efficiency. Real sessions vary with battery temperature, charger settings, the car's charging curve near full, and your utility's fixed charges, taxes, tiers, and seasonal prices. Your utility bill is the final word on what you pay.

We provide the site as is, without warranties of any kind, and we aren't responsible for decisions made from its estimates. Always check your utility's current rate schedule before choosing a plan or changing how you charge.

Where the numbers come from

• ZIP code lookup: "U.S. Electric Utility Companies and Rates: Look-up by Zip Code (2024)," published by the National Renewable Energy Laboratory (NREL) using U.S. Energy Information Administration Form 861 data. Licensed under CC BY 4.0. We show each utility's average residential price for 2024 (total residential revenue divided by kilowatt-hours sold) and changed the data's format so the site can look it up quickly. ZIP codes are matched to utilities approximately, and some areas, especially places with retail electricity choice, aren't covered.
• Utility time-of-use plans: prices and hours for the named utility plans were collected from each utility's published rate pages and tariffs (or, for SCE, a published summary of its posted prices) and were last checked October 9, 2026. Each plan links to its source. Utilities change prices regularly, and some listed prices leave out fixed charges, fuel adjustments, riders, or taxes, as noted on each plan. Holidays are treated like regular weekdays unless you choose the weekend/holiday option.
• Sample rate plans: the flat and time-of-use plans in the menu are illustrative examples, not any specific utility's tariff.
• Public charging comparison: uses the price you enter. The typical prices offered as shortcuts are examples, not any charging network's actual rate. Network prices vary by location, time, membership, and demand, and some networks bill by the minute or charge idle fees.
• Vehicle figures: battery sizes and maximum home-charging power are rounded from manufacturer and published specifications. Your vehicle's usable capacity may differ.

Trademarks

Tesla, Model 3, Model Y, Model S, Model X, Cybertruck, Ford, F-150 Lightning, Nissan, Leaf, and all utility names are trademarks of their respective owners. WhenToCharge is independent and is not affiliated with or endorsed by any automaker or utility.

Privacy

• No accounts or tracking: the site doesn't ask for your name or email, and doesn't use advertising or analytics cookies.
• Your settings stay in your browser: your vehicle, charge levels, ZIP code, and rate entries are saved in your own browser's local storage so they're there when you return. They aren't sent to us, and you can clear them at any time by clearing this site's data in your browser.
• ZIP lookups: when you look up a ZIP code, your browser downloads a regional data file from this site and finds the match itself. Your ZIP code isn't sent to us or to anyone else.
• Hosting: the site is hosted by Cloudflare, which processes standard technical information, such as IP addresses and the pages requested, to deliver and protect the site. See Cloudflare's privacy policy.
• Fonts and charts: the site's typefaces load from Google Fonts and its charting library loads from jsDelivr. Like any web server, those services receive your IP address when your browser requests the files.

If we add features that change any of this, such as analytics, ads, partner links, or contact forms, we'll update this page first.

Contact

Questions, corrections, or a rate that looks wrong for your area:

hello@whentocharge.com