Aquarium Calculators & Tools
Evidence-based calculations for aquarium volume, fish stocking density, water parameter safety, medication dosing, and equipment turnover.
Aquarium Calculators
1 ToolsAquarium Tools
8 ToolsFish Compatibility Calculator
Use the Coexistence Lab to cross-reference temperaments, temperature bounds, pH ranges, and swimming depths of freshwater species before adding them to your aquarium. Prevent territorial disputes, physical injury, and chemical shock before you buy.
Aquarium Nitrogen Cycle Tracker
Interpret current ammonia, nitrite, and nitrate readings as a broad indication of a possible aquarium cycle phase.
Aquarium Fish Stocking Calculator
Estimate realistic fish stocking capacity using adult size, bioload, filtration, swimming space, tank maturity, plants, and maintenance habits. Suitable for community tanks, cichlids, predators, and planted aquariums.
Aquarium Substrate Calculator
Calculate aquarium substrate volume and optional mass.
Aquarium Tank Volume Calculator
Estimate gross aquarium volume in gallons and liters from rectangular or cylindrical dimensions, plus rough water-and-glass weight.
True Water Volume Calculator
Estimate the net usable water volume in your aquarium.
Turtle Tank Size Calculator
Calculate gross aquarium capacity, actual water volume based on depth, and compare it against the general 10-gallons-per-inch of shell rule of thumb for aquatic turtles.
Aquarium Water Changes Calculator
Estimate a single water-change percentage and volume to dilute measured nitrate toward a selected target.
Calculators
28 ToolsAmmonia Dosing Calculator for Fishless Cycling
Estimate how much ammonia solution to add during a fishless aquarium cycle. For fishless cycling only; do not dose ammonia with fish or other aquatic animals in the tank.
Freshwater Ammonia Speciation Calculator (NH3)
Enter TAN as nitrogen (mg/L), pH, and temperature to estimate freshwater molecular NH3. This model assumes zero salinity and is not for brackish or marine water.
Annual Fish Keeping Cost Calculator
Estimate the true annual cost of your aquarium by entering tank volume, heater wattage, filter and light power, heater runtime, and local electricity rate. Get a practical itemized breakdown for heating, filtration, lighting, water, and routine consumables before you set up, upgrade, or troubleshoot a tank.
Aquarium Energy Cost & Electricity Calculator
Estimate the real electricity cost of running your aquarium by entering the wattage and daily runtime of heaters, filters, air pumps, return pumps, protein skimmers, wavemakers, and lights. Great for budgeting a first tank, comparing equipment, troubleshooting high power bills, or planning an efficient fish room.
Aquarium Heater Wattage Calculator & Size Guide
Prevent underpowering or overheating your tank with this interactive Aquarium Heater Size Guide. Calculate the ideal heater wattage based on your actual temperature delta – the difference between room temperature and target tank temperature. Get a safe wattage recommendation and learn why two smaller heaters are safer than one large one.
Aquarium Medication Dosage Calculator
Enter your tank size, substrate displacement, and medication type — get an exact safe dose based on true net water volume. Includes scaleless fish half-dose warnings for copper, formalin, and malachite green treatments.
Betta Fish Feeding Guide
Betta splendens require careful portion control because overfeeding is one of the most common causes of digestive distress and water-quality deterioration in small aquariums. This guide helps you evaluate your Betta's body condition and match it to appropriate qualitative feeding guidance — no invented pellet-count formulas.
Breeding Trigger Calculator
Many Amazonian and Asian fish species refuse to breed until the rainy season arrives. Enter your tank size, current temperature, target temperature drop, and cold water temperature — get the exact volume of RO water to add, the resulting TDS change, and a pre-conditioning checklist for your species.
Aquarium CO2 Cylinder Duration Estimator
Estimate how many days or months your pressurized CO2 cylinder will last before it needs a refill. Enter your cylinder size, bubbles per second, and daily photoperiod to get an accurate duration — no guesswork required.
Planted Tank Dry Fertilizer Calculator: Estimative Index (EI) Dosing
Skip expensive commercial liquid supplements. Calculate precise DIY macro and micro dry fertilizer doses in exact parts per million (ppm) for your planted tank using the proven Estimative Index method. Enter your tank volume and target nutrient levels — get exact grams to measure.
Aquarium Filter Turnover Rate Calculator
Never buy an underpowered filter again. Calculate exactly how much filter flow rate (turnover) your aquarium needs to keep water clear, ammonia zero, and fish healthy — based on your specific tank size, stocking density, and fish species.
"Why Is My Fish Dying?" Diagnostic Tool
Don't panic — most fish illnesses are treatable if caught early. Select the exact symptoms your fish is showing and our diagnostic engine will identify the most likely cause, whether it's Ich, Dropsy, ammonia poisoning, or a parasite — and walk you through exactly what to do right now to save them.
Fish Growth Rate Estimator
Most fish are sold as tiny 1-inch juveniles that look harmless in the store — but some will reach 12, 18, or even 24 inches within a year. Enter your fish's species category and current size to visualize exactly how fast it will grow, when it will outgrow your tank, and what size aquarium it will actually need as an adult.
Koi Feeding Temperature Guide
Koi (Cyprinus carpio) are poikilothermic: their digestive throughput is directly governed by water temperature. This guide provides temperature-responsive feeding guidance based on documented observations of Cyprinid feeding activity and gut evacuation rates — without universal hard cutoff thresholds that the scientific literature does not support.
Koi Pond Stocking Calculator
Koi are massive fish that produce immense amounts of biological waste. Calculate your pond's maximum adult Koi capacity based on volume and filtration metrics to prevent stunted growth, toxic nutrient accumulation, and lethal ammonia spikes.
Aquarium Light Duration & Photoperiod Calculator
Dial in the perfect photoperiod for your aquarium. Enter your tank type, plant density, and viewing schedule to calculate the optimal daily light duration that fuels plant growth, suppresses nuisance algae, and gives your fish a healthy day/night cycle — without guesswork.
Nitrite Toxicity Risk Calculator
Nitrite poisoning — known as Brown Blood Disease — can silently suffocate your fish even in a crystal-clear, well-oxygenated tank. This calculator factors in your actual pH and water temperature to show you exactly how toxic your nitrite reading is right now, and what you need to do about it.
Is My Tank Overstocked? Instant Checker
Wondering if you can squeeze in one more fish? This instant checker calculates the biological load of your current stocking against your tank size and filtration, tells you if you are overstocked, understocked, or right at the limit — and explains what to actually do about it.
pH Crash Recovery Calculator
Old Tank Syndrome causes catastrophic pH crashes that chemically burn fish gills — but fixing it too fast is just as deadly. This calculator generates a personalized, day-by-day buffering schedule based on your current pH, target pH, and tank volume, so you can raise the pH at a rate your fish can physiologically survive.
Pond Volume Calculator
Ponds are rarely perfect rectangles — and dosing chemicals based on a wrong volume estimate can kill every fish in your pond overnight. Enter your pond's shape, dimensions, and average depth to accurately calculate total water volume in gallons and litres, so every treatment, filter size, and pump rating is based on a number you can trust.
Aquarium Quarantine Duration & Protocol Calculator
One sick fish can crash an entire display tank in days. This calculator generates a personalized quarantine timeline and prophylactic medication schedule based on where you bought your fish, what species they are, and what symptoms — if any — are already visible. Know exactly what to treat, when to treat it, and when it is genuinely safe to move your new fish into your main tank.
Reef Auto Dosing Schedule Calculator
Knowing your daily dose is only half the battle. If your alkalinity and calcium pumps fire at the same time, they react on contact and precipitate into a useless calcium carbonate snowstorm — wasting expensive supplements and starving your corals. This calculator generates a staggered, optimised 24-hour micro-dosing schedule for your specific pump setup, keeping your reef chemistry rock-solid around the clock.
Marine Reef Two-Part Dosing Calculator: Alkalinity & Calcium Adjustment
Calculate safe two-part alkalinity and calcium corrections for reef tanks, including practical dosing context for SPS, LPS, mixed reefs, and beginners.
Salinity Temperature Correction Calculator
Convert and correct salinity readings so reef, marine, and brackish tanks are not adjusted from misleading hydrometer or refractometer results.
Aquarium Salt Dosing Calculator
Calculate safer aquarium salt doses for freshwater fish treatment, stress support, nitrite emergencies, quarantine tanks, and short-term parasite management. Avoid overdosing or harming salt-sensitive species.
Reef Salt Mix Brand Calculator
Calculates dry reef salt mix requirements across major commercial brands by volume or weight to hit target specific gravity.
Substrate Weight & Depth Calculator
Estimate substrate weight or bag count for sand, gravel, aquasoil, sloped aquascapes, planted tanks, cichlid tanks, and reef sand beds. Avoid running out mid‑setup or creating dangerous deep beds.
Aquarium Layout & Inspiration Builder
Choose an aquascaping direction based on hardscape, plants, maintenance level, livestock, budget, and whether you want a low-tech or high-tech layout. Avoid random decor and build a tank that suits your fish and your routine.