Calculator: How Many Liters Does A Fish Tank Hold?

The volume of an aquarium is an important indicator that every tank owner needs to know. It is important also to know how many liters does a fish tank hold. This is a value that gives an idea of ​​the quantitative and qualitative capabilities of the aquarium.

how many liters does a fish tank hold

It allows you to calculate the amount of additives and determine the parameters of filter installations, prepare the required amount of water for replacement, and perform a lot of other calculations. So how do you calculate volume?

is it important to calculate How many liters a fish tank holds?

The size of the tank is the value by which all calculations are made:

  • number and size of fish;
  • plant size;
  • soil and additives;
  • medicines.

All these calculations are based on the volume of the aquarium, so first you need to find out the parameters of your aquarium.

Inexperienced users often purchase tanks that are too small, which are not able to provide normal conditions for fish and plants. In addition, small aquariums have to be maintained much more frequently, which takes time and requires some effort.

Important! It must be remembered that an aquarium is an ecosystem in which all organisms participate on equal terms. If there is not enough living space for one group of plants or fish, this will affect the rest of the inhabitants.

how many liters does a fish tank hold: actual water volume

The actual volume is the amount of water actually present in the tank. It differs from the useful volume, which is calculated based on the total dimensions of the container. However, water is never poured to the very edge.

In addition, all additional factors affect:

  • glass thickness;
  • the volume of soil and bottom structures;
  • the number of plants, etc.

All add-ons occupy a certain space and reduce the actual volume of water.

What data and tools are needed?

  1. First of all, you need to choose the material for the tank. There are glass and acrylic containers, the wall thickness of which differs markedly. Acrylic is thicker than glass.
  2. The second step will be the choice of soil. The finer the fraction, the less it is necessary to make corrections for the loose packing of particles. If fine sand is used, it can be counted as a continuous backfill. For large stones (pebbles or fragments), the layer thickness in the calculation is reduced by 10-15%, depending on the shape of the stones.

For measurements you will need:

  • ruler or tape measure;
  • caliper for determining glass thickness;
  • calculator.

Reference! Sometimes you have to draw the bottom of the aquarium on a piece of paper so that you can conditionally divide it into simple shapes. This is done when calculating reservoirs of complex shape, which cannot be calculated in one simple operation.

how many liters does a fish tank hold? Correct calculations

Volume calculation is performed according to the following rules:

  • the internal size of the container is measured (outer size minus double the thickness of the glass);
  • a few centimeters (3-5) are subtracted from the full height, leaving some unfilled volume of the tank;
  • subtract a few centimeters of soil height;
  • determine the volume of bottom structures, and add the dimensions of the filters to them.

All additional volumes are subtracted from the calculated value, resulting in the actual amount of water in the aquarium.

formula applied to calculate How many liters does a fish tank hold?

The calculation is made by multiplying the area of ​​​​the base by the height of the water. The easiest way to calculate the volume of a parallelepiped is to multiply the width, length, and height in succession. Other methods are used to determine the volumes of more complex figures.

For example, if the aquarium has beveled corners, you need to draw the shape of the bottom on a piece of paper and conditionally divide it into simple components – rectangles and triangles. After that, it is easy to calculate the areas of individual figures and add them together.

To calculate the volume of a cylindrical (marine) aquarium, you need to calculate the bottom area:

S=πr^2 = πd2/4

The number π is known from the school course and is equal to 3.14. It is not always possible to measure the radius of the aquarium, it is easier to measure the diameter, square it and divide by 4. The main condition will be to measure the inner diameter, without the thickness of the glass. This will be the actual bottom area.

examples to calculate water tank capacity in liters

The easiest way to calculate the volume of the tank is the usual rectangular shape.

To calculate the volume, it is better to convert the value to cubic meters, so that later it will be easier to convert the result to liters.

One m 3 is equal to 1000 liters.

  • Let’s say its length-width-height are 50 30-35 cm, respectively.
  • We converted these dimensions into meters and determine the volume: 0.5 × 0.3 × 0.35=0,0525 м3
  • Then we convert the resulting value into liters: 0.0525 × 1000 = 52.5 liters

Calculation of a cylindrical vessel:

Determine the area of ​​the bottom. Let’s say the diameter is 30 cm. Then: (0.3): 4 = 0.09 : 4 = 0.0225 м2

Now the bottom area must be multiplied by the height of the water column (40 cm or 0.4 m) and converted the result into liters: 0.0225 × 0.4 = 0.009 m 3 . 0.009 × 1000 = 9 liters

How Many Liters Does A Fish Tank Hold?

The calculation of the useful volume of the aquarium is based on determining the total amount of water that will fit in an empty tank.

To do this, it is only necessary to determine the dimensions of the tank without taking into account the thickness of the glass.

In this case, it is not required to make adjustments for the soil, incomplete filling of the container, and for other additional elements.

Data and tools

To calculate the useful volume, you will need measuring tools (ruler, tape measure, caliper) and a calculator for calculations.

No additional tools are needed. In the passport of the aquarium (if any), some values ​ indicated – the thickness of the glasses, the total (geometric) volume, and other indicators. They can be used for calculations, which will simplify the task and speed up the result.

Calculation rules

The calculation is done according to the following rules:

  • Measure the length and width of the container, subtracting twice the thickness of the glass.
  • Measure the height of the aquarium. The easiest way is to use a ruler and immediately measure the internal height so as not to take away the thickness of the glass.
  • The final indicator is determined by the appropriate formulas.

Since it is necessary to determine the internal volume of the tank itself, the task is simplified and does not require additional actions.


Useful volume is determined by multiplying the base area by the height of the tank. The only exception may be a spherical aquarium, where the volume is calculated by the formula:

V=3/4​ π r3

It is very difficult to determine the usable area of ​​a spherical vessel since it is not a full-fledged ball – the cut top is missing. Therefore, most users follow the empirical path by filling a spherical aquarium with water from containers with a known volume.

To determine the volume of a hexagonal aquarium, use the formula for the area of ​ the hexagon multiplied by the height.

Formula: a is the square of the side of the hexagon. The resulting value is multiplied by the height of the tank and the resulting value is converted to liters.


To calculate the volume of a parallelepiped, you must successively multiply its length, width and height. It is more difficult to calculate the volume of a hexagonal aquarium.

Suppose there is a tank with a wall length of 30 cm, then the bottom area will be equal to:

(3 × √3 a)/2 = (3 × (1.7 × 0.09)) : 2 = 0.459 : 2 = 0.23 м2

Now it remains only to multiply this value by the height of the inner part. Let’s say it is 45 cm.

0.23 × 0.45 = 0.1 м3

To convert to liters, multiply the result by 1000 and get 100 liters.

The calculations may be too complicated for some users. To facilitate the task will help online calculators, of which there are many on the Internet. It is recommended to use several of them to check the results and avoid mistakes.

The amount of water in fish tank Depends upon

Different types of aquarium fish need their own sizes of living space.

For example, for small species (cardinal, guppy, or neon), 1 liter per fish is enough.

Larger species require much more space. For example, a pair of cichlids up to 10 cm in size will require about 40 liters.

Other Calculators:


How many liters does a fish tank holds cannot be calculated by the usual measurement of its geometric dimensions. Such a calculation will give too high a value, due to which the user will constantly make mistakes in the calculations of supplements and medicines.

It is necessary to take into account the volumes of additional elements (soil, structures), and subtract a certain amount of water that is not added to the upper edge of the container. You should not save time and effort, since this procedure is performed only once, and then it is used throughout the operation of the aquarium.

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