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CreativeEdges | Organic Aquarium Volume Calculator
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Organic Aquarium Volume Calculator

Nature-inspired precision tools — accurate water volume, glass compensation, and intelligent stocking guidance. Trusted by aquarists worldwide.

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3 Shapes
cm/mm/in
90% Real Fill
Glass Comp
🌿
🌱
✨

Realistic fish swimming — accurate calculations inside!

Precision Volume Calculator

Get accurate capacity in litres, UK & US gallons — designed for real-world aquarium use

cm mm inches
Subtracts wall displacement for true water volume

What is this Calculator & Why Do You Need It?

Essential Guide This is a professional-grade aquarium volume calculator designed specifically for fishkeepers. Unlike basic online tools, our calculator provides realistic water capacity after accounting for substrate, decor, and the air gap.

Why “Real Water Volume” is Critical: Most aquariums are marketed by gross dimensions. In reality, you fill only about 90% — substrate takes 5-10%, and you need a 2-3cm air gap. Use our realistic figures for medication dosing, filter sizing, and stocking.

📐 How to Use This Calculator

  1. Select tank shape — Rectangular, Cylinder, or Sphere.
  2. Choose unit — cm, mm, or inches.
  3. Enter dimensions and optional glass thickness.
  4. Click Calculate — Get realistic water volume, UK/US gallons, and stocking guideline.
  5. Copy CSV or Print — Save results for future reference.
Pro Tip: Click “Copy CSV” after calculation to save your results for medication dosing and aquarium journaling.

Common Tank Sizes: Real vs Stated Volume

Reference Guide

This professional reference table compares gross (empty) volume with realistic water volume after accounting for substrate (5-10%), decor, and the necessary 2-3cm air gap. Use the “Real Water” column for medication dosing, filter selection, and stocking decisions.

Gross Volume (Litres)Real Water (Litres)UK GallonsUS GallonsTypical Application
30 L~27 L5.9 gal7.1 galBetta / Shrimp / Nano Plants
60 L~54 L11.9 gal14.3 galNano Community / Small Tetras
100 L~90 L19.8 gal23.8 galCommunity Starter / Rasboras
180 L~162 L35.6 gal42.8 galCichlid / Planted / Angelfish
240 L~216 L47.5 gal57.0 galLarge Display / Discus / Reef
350 L~315 L69.3 gal83.2 galOscar / Large Cichlid / Marine

Glass Compensation

Subtracts wall displacement for true water volume.

Smart Stocking

Species-aware guidelines beyond “inch per gallon”.

Export Reports

Save calculations as CSV for your aquarium journal.

Frequently Asked Questions

How accurate is this calculator?
Our calculator uses precise geometric formulas and optional glass thickness compensation. For rectangular tanks with glass thickness entered, accuracy is within 0.5 litres.
Why do I need the 90% realistic fill?
Substrate displaces 5-10% of volume, and you always leave a 1-3cm air gap. Use realistic fill for medication and stocking.
Can I use this for saltwater/reef tanks?
Absolutely! For reef tanks, live rock displaces even more water — consider adding 10-15% extra displacement.
Is this tool really free?
Yes — 100% free, no ads, no signups, no tracking. Built by aquarists for aquarists.

Ready to calculate your exact water volume?

Professional-grade accuracy. No guesswork. Just honest numbers for a healthier aquarium.

CreativeEdges.org — Precision Aquarist Tools. Designed for conscious fishkeeping.
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