Aquarium Tools & Calculators
Practical calculators and utilities to help you maintain a healthy aquarium. No guesswork - just enter your numbers and get clear answers.
Keeping an aquarium healthy involves numbers - water change volumes, stocking limits, equipment sizing. These tools do the math so you can focus on your fish. Each calculator is based on established fishkeeping formulas and designed to give you practical, actionable results.
Whether you are setting up your first tank or maintaining a mature system, getting the numbers right matters. Underdosing medication leaves parasites alive. Oversizing a heater wastes energy and risks overheating. Converting between litres and gallons incorrectly throws off every calculation that follows. These tools take the guesswork out of the most common fishkeeping calculations so you can make confident decisions for your aquarium.
About our tools
- 4 tools available and growing
- Based on standard fishkeeping formulas
- Works for freshwater, marine & brackish setups
Available Tools
Free browser-based calculators and converters for everyday fishkeeping tasks. No sign-up required - just enter your numbers and get results.
Nitrate Water Change Calculator
Enter your current nitrate level and target concentration to find out exactly how much water to change. Works for any tank size, freshwater or saltwater.
Heater Size Calculator
Find the right heater wattage for your aquarium based on tank volume, target temperature, and room temperature. Properly sized heaters keep temperatures stable and reduce stress on fish.
Aquarium Volume Calculator
Calculate your tank volume in litres, US gallons, and UK gallons. Supports rectangular, cylindrical, and hexagonal shapes. Essential for dosing, stocking, and equipment sizing.
Aquarium Unit Converter
Convert between Celsius and Fahrenheit, litres and gallons, centimetres and inches. All the unit conversions fishkeepers need in one place.
Coming Soon
These tools are currently in development. Check back for updates.
Stocking Calculator
Plan your tank inhabitants based on tank volume, filtration capacity, and species compatibility. Avoid overcrowding and reduce aggression risks.
Frequently Asked Questions
Common questions about our aquarium tools and calculators.
Are these aquarium calculators free to use?
Yes. All tools on Piscora are completely free with no account required. They run directly in your browser and do not store any personal data.
How accurate is the nitrate water change calculator?
The calculator uses a standard dilution formula to estimate the water change volume needed to reach your target nitrate level. Results are a close approximation - actual nitrate levels can vary based on factors like bioload, feeding, and plant uptake. Always confirm with a test kit after performing water changes.
Can I use these tools for saltwater aquariums?
The nitrate water change calculator works for both freshwater and saltwater tanks since the dilution math is the same. Future tools will include options specific to marine setups where relevant.
What tools are planned for the future?
We are working on a stocking calculator to help you plan fish combinations for your tank size. More tools will follow based on what fishkeepers find most useful.
Why should I calculate water changes instead of just doing a fixed percentage?
A fixed percentage water change (like 25% weekly) is a good general habit, but it does not account for your actual nitrate levels. If nitrates are high after a missed water change or heavy feeding, you may need a larger change. The calculator tells you exactly how much water to replace to hit a safe target.
Related Guides
Learn more about the science behind the numbers. These guides explain the concepts our tools are built on.
Nitrate vs Nitrite
Understand the difference between these two nitrogen compounds and why both matter for fish health.
Read the guideTank Cycling
The nitrogen cycle is the foundation of a healthy tank. Learn how to cycle properly before adding fish.
Read the guideWater Changes
How often to change water, how much to replace, and the right way to do it without stressing your fish.
Read the guide