Free Aquarium Calculators

Interactive tools to help you plan and maintain the perfect aquarium. All free, no sign-up required.

Stocking Calculator

How many fish can your tank handle? Add species and get real-time bioload analysis, compatibility checks, and schooling warnings.

Calculate exact water change percentage based on nitrate levels. Includes personalized maintenance schedule and before/after visualization.

Find the right wattage heater based on tank size, room temperature, and target temperature. Product recommendations included.

How much gravel, sand, or aquasoil do you need? Supports sloped aquascaping layouts. Cost estimates included.

Calculate gallons and liters for rectangular, bowfront, cylinder, and hexagonal tanks. Common tank size presets.

Our calculators work best alongside these guides: