Work out what your own blanket costs

Number one: the wattage

The hard one, because most manufacturers do not publish it. Four places to look, in descending order of reliability.

1. 1A rating label on the blanket. Check the controller, the plug, and any sewn-in tag at the corner of the hem. This is the manufacturer's own figure for your exact unit and it beats everything else.
2. 2A plug-in energy monitor. About $20, reads actual draw in watts. Plug the blanket in, set it to the level you use, read the number. This is better than any published figure because it measures your blanket rather than the model.
3. 3The manufacturer's listing. Eight of the 29 products we track state a wattage there. Our compiled version is the watts, by model.
4. 4Nothing else. If none of the above gives you a number, you do not have one. That is an unsatisfying answer and it is the true one.

Number two: the hours

Easier, and worth being honest with yourself about. We default to eight hours because it approximates a night's sleep, but a lot of people use these products very differently.

The first row is the one worth noticing. Preheating and switching off costs about a cent and is how the cheapest possible use of a heated blanket looks. Several products build it in: Bedsure's preheat cycle and the selectable one-hour timers on Sunbeam and Serta all support exactly this pattern.

Number three: your rate

On your electricity bill, usually expressed as cents per kWh. Use that number, not ours.

We publish 18.34 cents because it is the US average residential rate for June 2026 from the EIA, and it is linked on every table that uses it. It is a national mean. US residential rates vary by more than a factor of two between states, so for any individual household it is approximately right at best.

Three mistakes that make online calculators wrong

1. 1Using a made-up wattage. The most common one. A 400 W assumption produces a figure four times too high for a 100 W blanket, and it will look perfectly authoritative.
2. 2Not stating the rate. A cost figure without a rate attached cannot be checked or adapted, which makes it useless outside whatever household the author had in mind.
3. 3Using a rate from the wrong country. Several of the better-written pages on this topic are British and price in pence at the Ofgem cap. Good work, wrong market, and converting it is worse than starting over.

Sanity-check your answer

When you have a number, check it against the range. Published heated blanket wattages run 100 W to 220 W, so at a typical US rate an eight-hour night should land somewhere between roughly 10 and 40 cents.

If your answer is a few dollars a night, you have almost certainly used a space-heater wattage by mistake. If it is a fraction of a cent, check whether you divided by 1000 twice. Those two account for most arithmetic errors here, and the per-night page has every published model worked out if you want something to compare against.