Aquarium Calculators & Tools
Free tools for planning, stocking, planting and maintaining your aquarium.
Aquarium tools
Aquarium Planner
Build a beginner-safe aquarium setup in a few minutes.
Fish Compatibility Checker
Check species conflicts, group requirements, aquarium size, and water parameters.
Aquarium Plant Problem Diagnosis Checker
Rank likely causes of aquarium plant symptoms using the Plant Database and aquarium context.
Aquarium Volume Calculator
Estimate aquarium volume based on dimensions, shape and water height.
Aquarium Stand Calculator
Check a defined stand or generate a DIY lumber frame, support layout and cut list.
Aquarium PAR Lighting Calculator
Calculate PAR, lux and photoperiod for planted aquariums and aquascapes.
Aquarium Nutrient Solution Calculator
Calculate dry fertilizer doses, nutrient contributions, and custom stock solutions for planted aquariums.
Aquarium Fertilizer Dosing Calculator
Calculate nutrient additions and visualize dosing over time for planted aquariums.
Aquarium Substrate Calculator
Calculate the volume you need and see current in-stock package combinations for soil, sand, or gravel.
Aquarium Heater Size Calculator
Estimate heater wattage based on aquarium volume and temperature difference.
Aquarium pH/KH/CO2 Calculator
Estimate CO2 levels from pH and KH values for freshwater aquariums.
Aquarium Calcium & Magnesium Calculator
Calculate calcium, magnesium, aquarium GH, and the Ca:Mg ratio from common water values.
Planning guidance
Free Aquarium Calculators for Better Planning
Aquarium calculators can make it easier to plan a freshwater aquarium before choosing equipment, plants or livestock. Start with your aquarium volume, then use that information when estimating heater size, fertilizer dosing, substrate requirements or other setup needs.
For planted aquariums, the lighting, fertilizer, substrate and CO₂ tools help you estimate important setup parameters. The Fish Compatibility Checker compares species requirements, while the Aquarium Planner brings several setup decisions together in one guided workflow.
Calculator results are planning estimates rather than fixed rules. Always consider your actual aquarium, livestock, plants and equipment, and make changes gradually.