Time-of-Use Savings Calculator
Would an off-peak plan save you money? See it for EV charging and shiftable home loads.
A time-of-use plan pays off when you can move a big, flexible load, usually overnight EV charging, into off-peak hours. Most EV households save $300–$800 a year. Homes that can’t shift much daytime use may save little, or pay more, since on-peak rates are higher than a flat rate.
A time-of-use (TOU) rate charges more during peak evening hours and much less overnight. Whether it saves you money depends on one thing: how much of your electricity you can move to the cheap window. For EV owners who charge overnight, that share is large.
This calculator compares your flat rate to a peak/off-peak plan for the load you can shift, and shows the yearly difference, the honest version, which counts the higher peak price on everything you can’t move.
How we calculate this
We price your total usage two ways: everything at your flat rate, versus the shiftable share at the off-peak rate and the rest at the on-peak rate. The difference is your yearly saving, or loss.
What affects your cost
How much you can shift
EV charging is the ideal shiftable load, schedule it for the off-peak window and a big block of usage moves to the cheap rate automatically.
The peak-to-off-peak gap
The wider the spread between on-peak and off-peak, the more shifting pays. Some plans halve the overnight rate; others barely differ.
Your daytime usage
Everything you use during peak hours costs more on a TOU plan. Homes with heavy evening AC or cooking can end up paying more than on a flat rate.
A smart meter
TOU plans need an interval (smart) meter to record when you use power. Most US utilities already have one installed, or add it free when you enroll.
Common questions
Is a time-of-use electricity plan worth it?+−
A TOU plan is worth it when you can move a big, flexible load, usually overnight EV charging, into off-peak hours. Most EV households save $300–$800 a year; homes that can’t shift much daytime use may save little or pay more.
What is the difference between on-peak and off-peak rates?+−
On-peak rates apply during high-demand hours (typically weekday late afternoon and early evening) and cost the most. Off-peak rates apply overnight, early morning, and often weekends, when grid demand is low and electricity is cheapest.
What time is off-peak electricity?+−
Off-peak hours are usually overnight and early morning, most commonly between about 9 PM and 7 AM on weekdays, plus many weekends and holidays. Exact windows vary by utility and season, so check your specific rate plan.
How much can you save charging your EV off-peak?+−
Many EV owners cut charging costs 30–60% by charging overnight on off-peak rates. Real-world savings often land around $300–$800 a year, depending on your utility’s peak-to-off-peak gap and how many miles you drive.
Is time-of-use better than a flat rate?+−
TOU beats a flat rate only if you can shift a meaningful share of usage, like EV charging, to off-peak hours. If most of your electricity is used during peak evening hours, a flat rate is usually cheaper.
When is the best time to charge an EV to save money?+−
The cheapest time is during off-peak hours, usually after 9 PM or midnight until early morning. Set a charge schedule on your car or Level 2 charger so charging starts automatically in the off-peak window.
Do I need a special meter for a time-of-use plan?+−
Most TOU plans need a smart (interval) meter that records when you use electricity. Many US utilities have already installed one; if not, they typically add it at no charge when you enroll.
Savings compare a flat rate against a peak/off-peak plan on your usage, counting the higher on-peak price on the share you can’t shift. Defaults model an EV household charging overnight. Real TOU windows, seasonal rates, and demand charges vary by utility, enter your plan’s numbers. Full methodology →