Stop the guesswork. Calculate volume, stocking, and safety with pro-grade data.
Calculate exact water volume for medication dosing, treatments, and equipment sizing. Supports all tank shapes with fill height adjustments.
Calculate exactly how much gravel, sand, or aquasoil you need. Includes water displacement for accurate volume calculations.
Calculate how many fish can safely live in your tank. Accounts for bioload, fish size, and tank volume.
Determine the right GPH flow rate and filter size for your tank. Compares HOB, Canister, and Sump requirements.
Size your heater correctly based on room temperature and tank volume. Includes safety tips for redundancy.
Calculate the perfect water change volume to reach your target nitrate levels. Keep your water chemistry stable.
Estimate the total weight of your aquarium including water, glass, and substrate. Ensure your floor can safely support the static load.
Calculate safety factors, bowing risk, and panel dimensions for DIY builds. Essential tool for custom tank design and structural peace of mind.
Underdosing won't cure sick fish. Overdosing can kill them. Precise volume measurements ensure treatments work safely and effectively.
Water weighs 8.34 lbs per gallon. A 55-gallon tank can exceed 700 lbs total. Know the weight before it's too late.
Size heaters, filters, and pumps correctly based on actual water volume. Save money and keep fish healthy.
Rectangular, bowfront, cylinder, corner tanks supported
Switch between gallons/inches and liters/cm instantly
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Calculate from your phone at the fish store
Maintaining a thriving aquarium is a delicate balance of biology, chemistry, and engineering. While the aesthetic beauty of a well-scaped tank is what draws many into the hobby, the underlying math is what keeps it alive. For decades, hobbyists relied on "rules of thumb" like the one-inch-per-gallon rule or generic filter sizing. Today, we know that these simplifications often lead to unstable environments, stressed livestock, and avoidable system failures. Success in the modern era of fishkeeping requires a transition from guesswork to precision data.
Modern aquarium science emphasizes precision. A 20-gallon "high" tank has a significantly different oxygen exchange rate and swimming area than a 20-gallon "long" tank, despite having identical volumes. Similarly, a heavily planted tank handles bioload differently than a minimalist cichlid setup. Our suite of calculators is designed to bridge the gap between complex aquatic science and everyday hobbyist needs, providing data-driven recommendations that respect the unique geometry and biology of your specific system. By calculating specific surface areas and metabolic demands, we provide a safer baseline for your aquatic pets.
Everything in your aquarium—from the temperature stability provided by your heater to the toxicity levels of ammonia—is a function of volume. However, the volume printed on your tank's box is rarely the volume of water it actually holds. Glass thickness, substrate depth, and hardscape displacement can reduce your actual water capacity by 10% to 25%. Understanding your "net volume" is the first step in responsible dosing and equipment selection. This knowledge allows you to calculate the precise "thermal mass" of your system, ensuring your heater is never underpowered during a cold snap.
The nitrogen cycle is the heart of every aquarium, but its capacity isn't infinite. Every inhabitant, from the smallest shrimp to the largest cichlid, adds to the biological demand on your system. Our tools help you quantify this demand by looking at more than just fish length. We consider the metabolic archetypes of different species, acknowledging that a messy eater like a goldfish requires vastly different filtration and volume than a lean, active tetra. This holistic view of stocking ensures that your beneficial bacteria colonies can keep pace with waste production, preventing toxic ammonia spikes that are the leading cause of fish mortality.
Whether you are a professional aquascaper planning a high-tech planted tank or a beginner setting up your first community aquarium, having access to accurate tools is essential. Our calculators utilize metabolic scaling for stocking, geometric formulas for irregular shapes, and density constants for various substrate types. By providing these resources for free, we hope to empower the community to create healthier, more stable aquatic environments for the animals in our care. We believe that better data leads to better decisions, and better decisions lead to a more rewarding and sustainable hobby for everyone.