Aquarium Calculators

Every number you need to plan and run a healthy tank, freshwater or saltwater. Free, instant, and sized to real-world equipment.

Tank & setup

Start here when planning a new build.

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Aquarium Volume

Gallons & liters from your dimensions, any tank shape.

⚖️

Tank Weight

Filled weight + floor-load safety check.

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Substrate / Gravel

Pounds of sand or gravel for your depth.

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Glass Thickness

Safe glass thickness for a DIY build.

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Setup Cost

Estimate the full startup cost of your tank.

Sizing equipment

Match gear to your exact tank.

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Heater Wattage

Right heater size for your volume & room temp.

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Filter Turnover (GPH)

Filter flow rate for healthy turnover.

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Lighting

Light output for fish-only or planted tanks.

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Air Pump / Flow

Circulation and powerhead sizing.

Stocking & livestock

Stock safely, avoid the overstocking trap.

🐟

Stocking / Bioload

How many fish your tank can really hold.

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Minimum Tank Size

Smallest tank a given species needs.

Water & maintenance

Keep your water dialed in.

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Water Change

Volume to change + dechlorinator dose.

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CO₂ (pH/KH)

Estimate dissolved CO₂ for planted tanks.

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Fertilizer Dosing

EI dosing for planted aquariums.

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Unit Converter

Gallons, liters, °F/°C, ppm and more.

Saltwater & reef

For marine and reef keepers.

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Salt Mix / Salinity

Salt needed for your target salinity.

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Reef Dosing

Alkalinity, calcium & magnesium dosing.

Aquarium Setup & Maintenance Planner

Take your calculator results off the screen and onto paper: stocking planner, water-test log, cycling tracker, and maintenance schedule, plus more.

Get the Planner for $39