Free aquarium tools - 17 calculators
Aquarium calculators for planning and water checks.
Practical aquarium tools for planning a tank, cycling, dosing, filtration, measurement conversion, marine salinity, running costs, stocking, maintenance, and planted care.
Browse all 17 toolsTool directory
Find the right aquarium calculator.
Search by measurement, aquarium type, equipment, or the problem you are trying to solve.
Showing 17 of 17 tools
Aquarium volume calculator
Calculate aquarium capacity from external tank dimensions in centimeters, inches, liters, or gallons.
Metric or imperialTank capacityCalculate volumePlanningAquarium stocking calculator
Build a freshwater or saltwater fish list and compare estimated load, adult size, temperature, pH, and temperament.
266 fishStocking estimatePlan stockingPlanted & aquascapingNitrate & phosphate ratio calculator
Use this Redfield ratio calculator to check NO3 and PO4 against planted aquarium nutrient targets.
NO3:PO4 ratioPreset targetsCheck nutrient ratioPlanted & aquascapingCO2 calculator
Estimate CO2 concentration from KH and pH readings for planted tank troubleshooting.
KH and pHCO2 ppmEstimate CO2Maintenance & waterAquarium water change calculator
Convert a routine percentage into liters or gallons, or estimate the change needed to reach a nitrate target.
Routine changesNitrate reductionCalculate water changeMaintenance & waterAquarium dosing calculator
Scale product-label doses to actual water volume and convert mL, pumps, US spoons, and product-specific grams.
Label scalingCustom pump sizeCalculate dosePlanted & aquascapingEI dosing calculator
Calculate transparent Estimative Index dry-salt doses with editable weekly ppm targets and carrier-potassium accounting.
KNO3 and KH2PO4Per-dose gramsCalculate EI dosesEquipmentAquarium heater size calculator
Estimate heater wattage from aquarium volume, room temperature, target water temperature, and tank top.
Temperature riseSuggested wattageSize your heaterEquipmentAquarium lighting calculator
Estimate LED lumen output from aquarium dimensions and the light demand of your plants.
Low to high demandTotal lumensEstimate lightingMaintenance & waterNitrogen cycle helper
Interpret ammonia, nitrite, and nitrate as a cautious cycle snapshot with fish-in warnings and confirmation steps.
Ammonia and nitriteCycle phaseCheck cycle statusEquipmentFilter flow & turnover calculator
Calculate delivered turnover and keep filter or sump flow separate from total reef display circulation.
Measured or rated flowEditable deratingCalculate turnoverMaintenance & waterAquarium unit converter
Convert volume, temperature, length, pump flow, GH, and alkalinity with explicit unit conventions.
US and UK gallonsTemperatureConvert unitsSaltwaterSalinity converter
Convert practical salinity and specific gravity with sample temperature and instrument context.
Specific gravityPractical salinityConvert salinitySaltwaterSalt mix calculator
Scale the exact salt product's directions for a new batch or plan separately mixed replacement water for a salinity correction.
Product-specific ratioReplacement-water planCalculate salt mixPlanningAquarium running cost calculator
Estimate monthly and annual electricity, water-change, and recurring supply costs.
Equipment schedulesHeater duty cycleEstimate running costPlanted & aquascapingAquarium substrate calculator
Calculate substrate volume from tank footprint, front depth, rear depth, and bag size for gravel, sand, or aquasoil.
Gravel and sandAquasoil bagsCalculate substratePlanted & aquascapingAquarium plant calculator
Estimate how many potted or in-vitro aquarium plants you need from the available planting footprint.
Planting footprintPots and in-vitro cupsEstimate plantsNot sure where to start?
Choose the situation that best matches the job in front of you. Each calculator turns familiar aquarium measurements into a practical planning result.
Planning a new aquarium
Start with the tank's working volume, then compare an early livestock plan before buying fish or equipment.
Choosing equipment
Compare heater capacity, planted-tank lighting, and delivered filter flow with the job each device needs to do.
Maintenance and water checks
Turn maintenance targets and water readings into a practical water-change, cycling, or product-dosing plan.
Planted tanks and aquascaping
Estimate substrate and plant quantities, then use water readings to add nutrient and CO2 context.
Saltwater preparation
Use temperature-aware salinity context, then scale the exact salt product's directions and verify the finished batch.
How accurate are the tools?
Every result should be treated as planning guidance, not a guarantee. Tanks vary by hardscape, substrate compaction, livestock, plant mass, lighting, filtration, and test kit accuracy.
Get the app
Take Aquarium Tracker with you.
Download on iOS or Android to log water tests, plan maintenance, and keep calculator results close to your tanks.
