Hot Tub Cost Calculator — Monthly & Annual Running Costs
Find out how much your hot tub really costs to run each month and year. Enter your energy use, electricity rate, chemical spend and water-refill details to get a full cost breakdown.
kWh/day
per kWh
per month
gallons
per year
per 1,000 gal
Electricity + chemicals + water (average per month)
879.75
per yearElectricity
31.1%
Chemicals
68.2%
Water
0.7%
- 1
Monthly electricity
5 × 0.15 × 30.44 = 22.83 - 2
Annual water cost
(400 ÷ 1000) × 3 × 5 = 6 - 3
Monthly water
6 ÷ 12 = 0.5 - 4
Monthly total
22.83 + 50 + 0.5 = 73.33
How does this calculator work?
Monthly hot tub cost = electricity (kWh/day × rate × 30.44) + chemicals + water refills ÷ 12. Electricity dominates at 50–70% of total cost. A typical US hot tub runs $80–$220/month; enter your actual energy use and rates to get an accurate personalised figure.
Formula
How this is calculated
Electricity is the biggest running cost for most hot tubs. A typical spa draws 3–7 kWh per day depending on insulation quality, set temperature, and how often the cover is left off. Multiply your daily kWh by your utility rate and by 30.44 (average days per month) to get the monthly electricity bill. Annual electricity is kWh/day × rate × 365.
Chemical costs cover sanitizers (chlorine or bromine), pH adjusters, shock treatments and other water-care products. Costs vary from around $30 for a careful owner to over $100/month for a heavily used tub. Enter your typical monthly spend and the calculator annualises it.
Water refills are needed 2–4 times a year to keep water chemistry manageable — divide annual gallons used (capacity × refills) by 1,000 and multiply by your water rate to get the annual water cost. All three components are summed and divided by 12 for the monthly figure. The values shown are estimates; actual costs depend on local utility tariffs, usage patterns, climate and equipment age.
Frequently asked questions
Most hot tubs use 3–7 kWh per day, averaging around 5 kWh. Well-insulated models in mild climates use less; older or poorly insulated tubs in cold weather can exceed 7 kWh. Check your before/after meter readings over a week for the most accurate figure.
A typical US hot tub costs $50–$120 per month in electricity (at roughly $0.15/kWh), plus $30–$100 in chemicals and a few dollars in water — totalling roughly $80–$220/month. Higher electricity rates or an inefficient heater can push this above $250/month.
Most manufacturers recommend draining and refilling every 3–4 months (3–4 times per year). A useful rule of thumb: divide the gallons by the number of daily users then by 12. Heavily used tubs may need more frequent changes to keep water chemistry stable.
Also known as
TG we-Calculate Editorial Team. (2026). Hot Tub Cost Calculator — Monthly & Annual Running Costs [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/hot-tub-cost-calculator
TG we-Calculate Editorial Team. "Hot Tub Cost Calculator — Monthly & Annual Running Costs." TG we-Calculate. 2026. https://we-calculate.com/calculator/hot-tub-cost-calculator.
TG we-Calculate Editorial Team, "Hot Tub Cost Calculator — Monthly & Annual Running Costs," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/hot-tub-cost-calculator
@misc{wecalculate_hot_tub_cost_calculator, title = {Hot Tub Cost Calculator — Monthly & Annual Running Costs}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/hot-tub-cost-calculator}}, year = {2026}, note = {TG we-Calculate} }
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