Free tools for planted aquarium hobbyists

Accurate calculators for every stage of the hobby — from setting up your first tank to dialling in your CO2.

Calculators & Tools

Nitrogen Cycle Tracker

Track your fishless cycle day by day — log ammonia, nitrite, and nitrate readings and get clear guidance on what to do next. Your readings are securely saved locally so you can come back daily and track progress through charts.

Start tracking

Tank Volume Calculator

Calculate tank capacity in litres and gallons from dimensions.

CO2 Calculator

Find dissolved CO2 ppm from pH and KH readings.

Electricity Cost Calculator

Calculate the running cost of your heater, light, and filter per year.

Heater Size Calculator

Find the right heater wattage for your tank size and room temperature.

Filter Flow Rate Calculator

Find the right filter flow rate for your tank size and setup type.

CO2 Refill Predictor

Predict when your CO2 cylinder will run out and get an estimated refill date.

Fertiliser Dosing Calculator

Generate a weekly EI fertiliser schedule or liquid dose for your tank volume.

Water Change Calculator

Work out how many water changes are needed to hit your target parameters.

RO Water Mixing Calculator

Calculate the exact ratio of RO and tap water to hit your target GH and KH.

Substrate Volume Estimator

Estimate substrate volume and weight, with bag quantity suggestions per substrate type.