Tank Gallons Calculator – How Many Gallons is My Fish Tank

Today in this blog ” How many gallons is my fish tank “, we will help you calculate the gallons of a tank and you will be able to know the gallons in your fish tank. There are 3 ways to know gallons.

1. Tank Gallons Calculator

In the tank gallon calculator, you can add the dimensions of your fish tank in either imperial of metric units.

Fish Tank Gallons Calculator

Width:
Length:
Depth:

Result: US Gallons Imperial Gallons

2. Tank gallons calculation using the formula

This is a simple three-step method, which will help you to calculate gallons.

A. Calculation of gallons of a rectangular tank:

Step 1: DO THE MEASUREMENT

Measure the dimension of the fish tank such as length (L), width (W), and depth (D).

Step 2: CALCULATE VOLUME

For a rectangular fish tank, the volume calculation formula is :

Volume = Length (L) X Width ( W) X Depth ( D )

Step 3: CONVERT VOLUME IN GALLONS

1 US Gallon = 231 cubic inches / 0.13368 cubic feet / 0.003785 cubic meters / 3.7854 liters

1 imperial Gallon = 277.419 cubic inches / 0.16054 cubic feet / 0.004546 cubic meters / 4.546 liters

Examples

Calculations in US customary units and in the Imperial system

Consider a rectangular tank of 25 inches in length and 15 inches in width with a depth of 18 inches

Volume = 25 X 15 X 18 cubic inches

Volume = 6750 cubic inches

US gallons = 6750 / 231 = 29.221 (1 US gallon = 231 cubic inches )

Imperial gallons = 6750 / 277.419 = 24.3314 (1 Imperial gallon = 277.419 cubic inches )

Calculations in the metric system

Consider a rectangular tank of 1 meter in length and 0.5 meters in width with a depth of 0.5 meters.

Volume = 1 X 0.5 X 0.5 cubic meters

Volume = 0.25 cubic meters

US gallons = 0.25 / 0.003785 = 66 gallons (1 US gallon = 0.003785 cubic meters )

Imperial Gallons = 0.25 / 0.004546 = 55 gallons (1 imperial gallon = 0.004546 cubic meters )

B. Calculation of gallons of a circular tank :

Step 1: DO THE MEASUREMENT

Measure the dimensions of the fish tank such as diameter (Dia) and depth (D).

Step 2: CALCULATE VOLUME

For a Circular fish tank, the volume calculation formula is :

Volume = Pie X Diameter (Dia) X Diameter (Dia) X Depth ( D ) / 4

Step 3: CONVERT VOLUME IN GALLONS

1 US Gallon = 231 cubic inches / 0.13368 cubic feet / 0.003785 cubic meters / 3.7854 liters

1 imperial Gallon = 277.419 cubic inches / 0.16054 cubic feet / 0.004546 cubic meters / 4.546 liters

Examples

Calculations in US customary units and in the Imperial system

Consider a circular tank of 40 inches in dia with a depth of 18 inches

Volume = 3.14 X 40 X 40 X 18 / 4 inches feet

Volume = 22608 cubic inches

US gallons = 22608 / 231 = 81.494 (1 US gallon = 231 cubic inches )

Imperial gallons = 22608 / 277.419 = 97.87 (1 Imperial gallon = 277.419 cubic inches )

Calculations in the metric system

Consider a circular fish tank of 1 meter in dia with a depth of 0.5 meters

Volume = 3.14 X 1 X 1 X 0.5 / 4 cubic meters

Volume = 0.3925 cubic meters

US gallons = 0.3925 / 0.003785 = 103.7 gallons (1 US gallon = 0.003785 cubic meters )

Imperial Gallons = 0.3925 / 0.004546 = 86.34 gallons (1 imperial gallon = 0.004546 cubic meters )

C. Calculation of gallons of a triangular tank :

Step 1: DO THE MEASUREMENT

Measure the dimensions of the fish tank such as sides ( S1, S2 & S3) and depth (D).

Step 2: CALCULATE VOLUME

For a triangular fish tank, the volume calculation formula is :

In triangular shapes, we need to calculate semi-perimeter before calculating volume.

Semi perimeter SP = ( S1 + S2 + S3 ) / 2

Volume = Square root ( SP X ( SP – S1 ) X ( SP – S2 ) X ( SP – S3 ) X Depth ( D ) / 4

Step 3: CONVERT VOLUME IN GALLONS

1 US Gallon = 231 cubic inches / 0.13368 cubic feet / 0.003785 cubic meters / 3.7854 liters

1 imperial Gallon = 277.419 cubic inches / 0.16054 cubic feet / 0.004546 cubic meters / 4.546 liters

Examples

Calculations in US customary units and in the Imperial system

Consider a Triangular fish tank with sides 25 inches, 20 inches, and 15 inches with a depth of 12 inches.

Semi-perimeter SP = ( 25 + 20 + 15 ) / 2 = 30

Volume = Square root ( 30 X ( 30 – 25 ) X ( 30 – 20) X ( 30 – 15) ) X 12 cubic inches

Volume = Square root ( 30 X 5 X 10 X 15 ) X 12 cubic inches

Volume = Square root ( 22500) X 12 cubic inches

Volume = 150 X 12 cubic inches

Volume = 1800 cubic inches

US gallons = 1800 / 231 = 7.79 (1 US gallon = 231 cubic inches )

Imperial gallons = 1800 / 277.419 = 6.49 (1 Imperial gallon = 277.419 cubic inches )

Calculations in the metric system

Consider a Triangular fish tank of sides 1 meter, 1 meter, and 1 meter in dia with a depth of 0.5 meters

Semi-perimeter SP = ( 1 + 1 + 1 ) / 2 = 1.5

Volume = Square root ( 1.5 X ( 1.5 – 1 ) X ( 1.5 – 1 ) X ( 1.5 – 1 ) ) X 0.5 cubic meters

Volume = Square root ( 1.5 X 0.5 X 0.5 X 0.5 ) X 0.5 cubic meters

Volume = Square root ( 0.1875) X 0.5 cubic meters

Volume = 0.433 X 0.5 cubic meters

Volume = 0.2165 cubic meters

US gallons = 0.2165 / 0.003785 = 57 gallons (1 US gallon = 0.003785 cubic meters )

Imperial Gallons = 0.2165 / 0.004546 = 47 gallons (1 imperial gallon = 0.004546 cubic meters )

D. Calculation of gallons of a square tank :

Step 1: DO THE MEASUREMENT

Measure the dimension of the fish tank such as length (L), and depth (D).

Step 2: CALCULATE VOLUME

For a square fish tank, the volume calculation formula is :

Volume = Length (L) X Length (L) X Depth ( D )

Step 3: CONVERT VOLUME IN GALLONS

Step 3: CONVERT VOLUME IN GALLONS

1 US Gallon = 231 cubic inches / 0.13368 cubic feet / 0.003785 cubic meters / 3.7854 liters

1 imperial Gallon = 277.419 cubic inches / 0.16054 cubic feet / 0.004546 cubic meters / 4.546 liters

Examples

Calculations in US customary units and in the Imperial system

Consider a square tank of 30 inches in length with a depth of 24 inches

Volume = 20 X 20 X 24 cubic inches

Volume = 9600 cubic inches

US gallons = 9600 / 231 = 41.56 (1 US gallon = 231 cubic inches )

Imperial gallons = 9600 / 277.419 = 34.6 (1 Imperial gallon = 277.419 cubic inches )

Calculations in the metric system

Consider a square tank of 1 meter in length with a depth of 0.5 meters

Volume = 1 X 1 X 0.5 cubic meters

Volume = 0.5 cubic meters

US gallons = 0.5 / 0.003785 = 132 gallons (1 US gallon = 0.003785 cubic meters )

Imperial Gallons = 0.5 / 0.004546 = 110 gallons (1 imperial gallon = 0.004546 cubic meters )

E. Calculation of gallons of a round tank :

Step 1: DO THE MEASUREMENT

Measure the dimensions of the fish tank such as diameter = DIA

Step 2: CALCULATE VOLUME

For a rectangular pool, the volume calculation formula is :

Volume = Pie X Diameter (Dia) X Diameter (Dia) X Diameter (Dia) / 4

Step 3: CONVERT VOLUME IN GALLONS

1 US Gallon = 231 cubic inches / 0.13368 cubic feet / 0.003785 cubic meters / 3.7854 liters

1 imperial Gallon = 277.419 cubic inches / 0.16054 cubic feet / 0.004546 cubic meters / 4.546 liters

Examples

Calculations in US customary units and in the Imperial system

Consider a round fish tank of 18 inches in diameter

Volume = pie X 18 X 18 X 18 / 4 cubic inches

Volume = 3053.63 cubic inches

US gallons = 3053.63 / 231 = 11 (1 US gallon = 231 cubic inches )

Imperial gallons = 3053.63 / 277.419 = 13.23 (1 Imperial gallon = 277.419 cubic inches )

Calculations in the metric system

Consider a round fish tank of 0.5 meters

Volume = 3.14 X 0.5 X 0.5 X 0.5 / 6 cubic meter

Volume = 0.006545 cubic meters

US gallons = 0.006545 / 0.003785 = 17.29 gallons (1 US gallon = 0.003785 cubic meters )

Imperial Gallons = 0.006545 / 0.004546 = 14.4 gallons (1 imperial gallon = 0.004546 cubic meters )

Summary – How many gallons is my fish tank

• Fish tank gallons can be determined by
• Online calculator
• Calculations
• Using table
• 1 US Gallon = 231 cubic inches / 0.13368 cubic feet / 0.003785 cubic meters / 3.7854 liters
• 1 imperial Gallon = 277.419 cubic inches / 0.16054 cubic feet / 0.004546 cubic meters / 4.546 liters
• 1 Cubic Foot = 7.48 US Gallons / 6.23 Imperial Gallons
• 1 Cubic meter = 264.17 US Gallons / 220 Imperial gallons