How many watts does a hot tub use?
A hot tub draws 4,000–5,500 watts while running, which is 16.7–22.9 amps on a 240 V circuit.
Hot tub watts, amps and circuit
| Running watts | 4,000–5,500 W |
|---|---|
| Voltage | 240 V |
| Running amps | 16.7–22.9 A |
| Circuit | 50 A breaker, dedicated circuit |
| Wire size (copper, NM-B cable) | 6 AWG |
Also called: spa, jacuzzi.
Hot tub watts by size and type
| Size or type | Running watts, W | Volts, V | Amps, A | Starting watts, W |
|---|---|---|---|---|
| Hot tub | 4,000–5,500 | 240 | 16.7–22.9 | — |
| Heater on 120 V (plug-in spa) | 1,000–1,250 | 120 | 8.3–10.4 | — |
What size generator runs a hot tub?
A hot tub needs a generator that supplies at least 5,500 running watts. Starting a hot tub takes a short surge of several times its running watts, and the surge is not listed here: size the generator from the locked-rotor amps (LRA) on the nameplate or the maker's generator guidance, not from the running watts. The generator must have a 240 V outlet or be connected through a transfer switch or interlock.
What it costs to run a hot tub
Running a hot tub at 4,750 W, the middle of its 4,000–5,500 W range, for one hour a day uses 1,733.8 kWh a year. That costs about $312 a year at $0.18 per kWh, the US average residential price for August 2026.
Your bill's total ÷ kWh used. 0.18 is the US residential average.
- Per day
- $0.85
- Per year
- $312
- Energy per day
- 4.75 kWh
- Energy per month
- 144.5 kWh
How it is calculated
- kWh per day = 4,750 W × 1 h ÷ 1,000 = 4.75
- Per month = 4.75 kWh × 30.4 days × $0.18 = $26
What affects hot tub power use
The running watts are the water heater, which draws the most: 4 to 5.5 kW on a 240 V tub. The pumps add more when the jets run. A good cover and the outdoor temperature decide how often the heater runs. Many 240 V hot tubs need a dedicated 50 A circuit through a GFCI; some smaller ones run on 30 A or 40 A, and on 30 A the heater may not run while the jets do. Follow the spa's manual.
How the amps are calculated
Amps = watts ÷ volts. For 5,500 W at 240 V that is 22.9 A. The 4,000–5,500 W range covers typical models; the nameplate on a hot tub gives the exact figure.