CalcStack — free, instant, no signup. The interactive calculator loads automatically.
A 100 W device running 8 hours a day at $0.17/kWh costs $49.64 a year. The dryer: $0.38 a load. The math your utility hopes you never do.
Electric bills arrive as one opaque number — this calculator decomposes it. Every device is watts × hours ÷ 1000 = kWh, times your rate. Price the dryer load ($0.38), the always-on server, the second fridge in the garage, and the space heater that quietly out-earns your raise in the wrong direction.
Anyone staring at a power bill uses it: 100 W × 8 h at $0.17/kWh is $49.64 a year — price every appliance, find the vampires.
The hierarchy is consistent: HVAC dominates at 40–50% of a typical bill (a 3.5 kW central AC running 6 hours daily is $107/month at average rates), water heating second at ~14–18% (4.5 kW element, ~2 hours of run time), then the dryer ($0.38/load adds up to $46/year at 3 loads weekly), refrigeration ~8%, and lighting now under 5% thanks to LEDs. The vampire tier deserves its audit: cable boxes and game consoles idle at 10–30 W continuously — $15–45/year each for doing nothing. The audit method that works: run this calculator on the top five suspects, and you will find 80% of the bill. A $20 plug-in kill-a-watt meter catches the liars whose labels don't match real draw.
It is on the bill but disguised: divide the total dollar amount by total kWh used — that blended number (usually $0.12–0.25 nationally, ~$0.17 average) is the honest rate because it includes delivery charges and fees that the advertised "generation rate" hides. Watch the traps: tiered pricing (rate jumps after a baseline), time-of-use plans (peak afternoon power can cost 2–3× off-peak — huge for EV charging timing), and fixed monthly charges that make your marginal kWh cheaper than your average. Hawaii (~$0.40+), California (~$0.30), and the Northeast run high; Louisiana, Washington, and Idaho (~$0.10) are the cheap seats — which is why EV economics and heat-pump math flip completely by state.
Yes — standby ("vampire") draw typically runs 1–10 W per device, and a house full of them burns 50–100 W continuously: $75–150/year. The offenders: cable/DVR boxes (20–45 W even "off" — among the worst), game consoles on instant-on (10–15 W), smart speakers (2–4 W), chargers left plugged in (~0.3 W, negligible despite the reputation), and anything with a clock display. The math decides which battles matter: a 25 W DVR costs $37/year — smart-strip territory; a 0.3 W phone charger costs 45 cents — ignore it. Rule of thumb for the audit: every watt of 24/7 draw costs about $1.50/year at average rates, so round up the usual 10 W+ suspects and unplug with confidence.