Aquarium running-cost calculator

Your full monthly cost, not just the power bill. The values filled in are examples, so replace them with your own. Your inputs are saved on this device only.

1. Electricity

Electricity rate ($ per kWh):

Check your utility bill. ReefKalk cites about $0.17 as the US average (source). Duty cycle is the share of time a device draws power while it's on. Heaters often run 20–40% of the time in a heated room, according to the same source.

Device	Watts	Hours/day	Duty %	kWh/mo	$/mo

Total: ·

2. Consumables

Water change, gallons per week Salt price per bucket or bag ($) Gallons that bucket mixes Top-off (evaporation), gallons per day RODI resin/cartridge cost ($) Gallons per resin/cartridge RODI filters & membrane, $ per year Food, $ per month Testing (kits, reagents), $ per month Additives & dosing, $ per month Filter media (carbon, GFO, socks, floss), $ per month

Salt and RODI water are calculated from your water-change and top-off volumes (weekly × 52 ÷ 12). Freshwater tank? Leave salt at $0.

Monthly

Yearly

Cost breakdown

Where to save

See the cheapest good options by category →

Formula: kWh/month = watts × hours/day × duty × 30.44 ÷ 1000. Monthly cost = kWh × rate + consumables.