Aqulator is a free aquarium calculator and fish tank manager for freshwater and saltwater tanks. Get accurate stocking levels and chemical doses in seconds.

Check tank mate compatibility across 250+ species. Track water test results over time. One aquarium app instead of ten bookmarks.

CALCULATORS

🐠 Stocking Calculator
Calculate exactly how many fish your aquarium can support based on volume and species bioload. Enter your tank size and get an accurate stocking level without rough rules of thumb. The calculator also surfaces recommended water parameters for every species you stock so you always know what conditions to maintain.

🔀 Fish Compatibility Checker
Check tank mate compatibility across 250+ freshwater and saltwater species before you buy. Aqulator flags conflicts in temperament and water parameter needs, then explains exactly why a pairing doesn't work so you can make an informed decision.

⚗️ Chemical Dosing Calculator
Get the exact dose for over 450 aquarium chemicals based on your tank volume. Each product includes safety warnings and detailed dosage output so you know exactly what you're adding to your aquarium.

🌿 CO2 Calculator
Calculate the right CO2 injection rate for planted tanks based on volume and plant load. Keeps your aquarium plants healthy without harming fish.

📐 Tank Volume Calculator
Calculate gallons or liters for rectangular, cylindrical, bowfront, and hexagonal aquarium shapes. Also shows the filled weight so you know what your floor is holding before you set up.

🌡️ Heater Wattage Calculator
Find the right heater wattage for your aquarium size and room temperature.

⚠️ Ammonia Toxicity Calculator
Check whether your ammonia levels are dangerous based on pH and temperature. Ammonia toxicity shifts dramatically with pH - this calculator accounts for that.

🪨 Substrate Calculator
Calculate how much gravel or sand your aquarium needs for your target depth and tank footprint.

⚖️ Weight Calculator
Know how heavy your full aquarium setup will be before you fill it.

💧 Water Change Calculator
Get the right water change percentage and frequency based on your stocking level.

🔄 Unit Converter
Imperial to metric conversion for every common aquarium measurement.

TANK MANAGEMENT

🏠 My Tanks
Create a profile for each freshwater or saltwater aquarium you own. Calculators, reminders, logs, and history all connect back to it. Switch between tanks from anywhere in the app so managing multiple aquariums stays organized.

⏰ Reminders
Set aquarium maintenance reminders tied to your tanks and schedule. The dosing calculator feeds directly into reminders so you can schedule a treatment with the exact dose already filled in. Turn on personality mode and get notifications written from your fish's perspective using the names you gave them.

📊 Water Test Log
Track water test results and chemistry readings over time so you can spot problems before they get serious. Maintenance records sit alongside your parameter history for a complete picture of each aquarium.

📋 Calculation History
Every calculation you run saves to your history. Reference past results or rerun them with updated numbers any time.

🔓 AQULATOR PRO

Free users get full access to every aquarium calculator with two tanks and three reminders each. Upgrade to Pro to unlock:

• Unlimited tanks and reminders
• Full database of 250+ fish species and 450+ chemicals
• Aquarium planner and fish recommender
• Backup, export, and import your aquarium data
• Cross-device sync
• Calculation and tank activity history
• Support independent development
• More features coming soon

One-time purchase. Yours forever. No subscription.

Whether you're setting up your first fish tank or managing a multi-tank fishroom, Aqulator is the free aquarium app built for real fishkeepers. Download it and stop guessing.

Aqulator Labs

Additional Information