Online Pool Volume Calculator – How Many Gallons Are In My Pool

Knowledge of pool gallons is one of the key steps toward pool maintenance. This figure is essential as it is required to calculate the chemical requirement quantity and the heater requirements of the pool. In the blog – ” How many gallons are in my pool “, we help you to know gallons in 3 ways.

1. Pool Gallons Calculator

In the pool gallon calculator, you can add the dimensions of the pool and calculate the gallons online

Pool Gallons Calculator

Width:
Length:
Depth 1 :
Depth 2 :

Result: US Gallons Imperial Gallons

2. Calculation using formula

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

A. Calculation of gallons in a rectangular pool :

Step 1: DO THE MEASUREMENT

Measure the dimension of the pool such as length (L), width (W), and depth (D). If there are two depths denote D1 for the shallow end and D2 for the deep end.

Step 2: CALCULATE VOLUME

For a rectangular pool, the volume calculation formula is :

CASE 1 – Uniform depth

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

CASE 2 – Depth varies at two ends

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

Average Depth ( D ) = ( Depth D1 + Depth D2 ) / 2

Step 3: CONVERT VOLUME IN GALLONS

CASE 1 – Measurement in US customary units or Imperial system i.e. feet

1 Cubic Foot = 7.48 US Gallons

1 Cubic Foot = 6.23 Imperial Gallons

CASE 2 – Measurement in Metric system i.e. meters

1 Cubic meter = 264.17 US Gallons

1 Cubic meter = 220 Imperial Gallons

Examples

Calculations in US customary units and in the Imperial system

Consider a rectangular pool of 20 feet in length and 10 feet in width with a depth of 5 feet and 10 feet respectively

Average depth = ( 5 + 10 ) / 2 = 7.5 feet

Volume = 20 X 10 X 7.5 cubic feet

Volume = 1500 cubic feet

US gallons = 7.48 X 1500 = 11220 as 1 cubic foot = 7.48 US gallons

~ 11200

Imperial gallons = 6.23 X 1500 = 9345 as 1 cubic foot = is 6.23 Imperial gallons

~ 9300

Calculations in the metric system

Consider a rectangular pool of 12 meters in length and 5 meters in width with a depth of 1.5 meters and 3 meters respectively

Average depth = ( 1.5 + 3 ) / 2 = 2.25 meters

Volume = 12 X 5 X 2.25 cubic meters

Volume = 135 cubic meters

US gallons = 135 X 264.17 = 35663

~ 35700

Imperial Gallons = 135 X 220 = 29700

B. Calculation of gallons in a circular pool :

Step 1: DO THE MEASUREMENT

Measure the dimension of the pool such as diameter (Dia) and depth (D). If there are two depths denote D1 for the shallow end and D2 for the deep end.

Step 2: CALCULATE VOLUME

For a Circular pool, the volume calculation formula is :

CASE 1 – Uniform depth

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

= 3.14 X Dia X Dia X D / 4

CASE 2 – Depth varies at two ends

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

Average Depth ( D ) = ( Depth D1 + Depth D2 ) / 2

Step 3: CONVERT VOLUME IN GALLONS

CASE 1 – Measurement in US customary units or Imperial system i.e. feet

1 Cubic Foot = 7.48 US Gallons

1 Cubic Foot = 6.23 Imperial Gallons

CASE 2 – Measurement in Metric system i.e. meters

1 Cubic meter = 264.17 US Gallons

1 Cubic meter = 220 Imperial gallons

Examples

Calculations in US customary units and in the Imperial system

Consider a circular pool of 20 feet in dia with a depth of 5 feet and 10 feet respectively

Average depth = ( 5 + 10 ) / 2 = 7.5 feet

Volume = 3.14 X 20 X 20 X 7.5 / 4 cubic feet

Volume = 2355 cubic feet

US gallons = 7.48 X 2355 = 17615 as 1 cubic foot = 7.48 US gallons

~ 17600

Imperial gallons = 6.23 X 2355 = 14671 as 1 cubic foot = is 6.23 Imperial gallons

~ 14700

Calculations in the metric system

Consider a circular pool of 12 meters in dia with a depth of 1.5 meters and 3 meters respectively

Average depth = ( 1.5 + 3 ) / 2 = 2.25 meters

Volume = 3.14 X 12 X 12 X 2.25 / 4 cubic meters

Volume = 2354 cubic meters

US gallons = 2354 X 264.17 = 67189

~ 67200

Imperial Gallons = 2354 X 220 = 55955

~ 56000

C. Calculation of gallons in a triangular pool :

Step 1: DO THE MEASUREMENT

Measure the dimension of the pool such as sides ( S1, S2 & S3) and depth (D). If there are two depths denote D1 for the shallow end and D2 for the deep end.

Step 2: CALCULATE VOLUME

For a triangular pool, the volume calculation formula is :

CASE 1 – Uniform depth

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

CASE 2 – Depth varies at two ends

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

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

Average Depth ( D ) = ( Depth D1 + Depth D2 ) / 2

Step 3: CONVERT VOLUME IN GALLONS

CASE 1 – Measurement in US customary units or Imperial system i.e. feet

1 Cubic Foot = 7.48 US Gallons

1 Cubic Foot = 6.23 Imperial Gallons

CASE 2 – Measurement in Metric system i.e. meters

1 Cubic meter = 264.17 US Gallons

1 Cubic meter = 220 Imperial Gallons

Examples

Calculations in US customary units and in the Imperial system

Consider a Triangular pool of sides 25 feet, 20 feet, and 15 feet with a depth of 5 feet and 10 feet respectively

Average depth = ( 5 + 10 ) / 2 = 7.5 feet

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

Volume = Square root ( 30 X ( 30 – 25 ) X ( 30 – 20) X ( 30 – 15) ) X 7.5 cubic feet

Volume = Square root ( 30 X 5 X 10 X 15 ) X 7.5 cubic feet

Volume = Square root ( 22500) X 7.5 cubic feet

Volume = 150 X 7.5 cubic feet

Volume = 1125 cubic feet

US gallons = 7.48 X 1125 = 8437 as 1 cubic foot = 7.48 US gallons

~ 8400

Imperial gallons = 6.23 X 1125 = 7008 as 1 cubic foot = is 6.23 Imperial gallons

~ 7000

Calculations in the metric system

Consider a Triangular pool of sides 12 meters, 10 meters, and 8 meters in dia with a depth of 1.5 meters and 3 meters respectively

Average depth = ( 1.5 + 3 ) / 2 = 2.25 meters

Semi-perimeter SP = ( 12 + 10 + 8 ) / 2 = 15

Volume = Square root ( 15 X ( 15 – 12 ) X ( 15 – 10 ) X ( 15 – 8 ) ) X 2.25 cubic meters

Volume = Square root ( 15 X 3 X 5 X 7 ) X 2.25 cubic meters

Volume = Square root ( 1575) X2.25 cubic meters

Volume = 39.69 X 2.25 cubic meters

Volume = 89.3 cubic meters

US gallons = 89.3 X 264.17 = 23590

~ 23600

Imperial Gallons = 89.3 X 220 = 19646

~ 19600

D. Calculation of gallons in a square pool :

Step 1: DO THE MEASUREMENT

Measure the pool’s dimensions such as length (L), and depth (D). If there are two depths denote D1 for the shallow end and D2 for the deep end.

Step 2: CALCULATE VOLUME

For a square pool, the volume calculation formula is :

CASE 1 – Uniform depth

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

CASE 2 – Depth varies at two ends

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

Average Depth ( D ) = ( Depth D1 + Depth D2 ) / 2

Step 3: CONVERT VOLUME IN GALLONS

CASE 1 – Measurement in US customary units or Imperial system i.e. feet

1 Cubic Foot = 7.48 US Gallons

1 Cubic Foot = 6.23 Imperial Gallons

CASE 2 – Measurement in Metric system i.e. meters

1 Cubic meter = 264.17 US Gallons

1 Cubic meter = 220 Imperial Gallons

Examples

Calculations in US customary units and in the Imperial system

Consider a square pool of 20 feet in length with a depth of 5 feet and 10 feet respectively

Average depth = ( 5 + 10 ) / 2 = 7.5 feet

Volume = 20 X 20 X 7.5 cubic feet

Volume = 3000 cubic feet

US gallons = 7.48 X 3000 = 22440 as 1 cubic foot = 7.48 US gallons

~ 22400

Imperial gallons = 6.23 X 3000 = 18690 as 1 cubic foot = is 6.23 Imperial gallons

~ 18700

Calculations in the metric system

Consider a square pool of 12 meters in length with a depth of 1.5 meters and 3 meters respectively

Average depth = ( 1.5 + 3 ) / 2 = 2.25 meters

Volume = 12 X 12 X 2.25 cubic meters

Volume = 324 cubic meters

US gallons = 324 X 264.17 = 85591

~ 85600

Imperial Gallons = 324 X 220 = 71280

~ 71300

Summary

• Pool gallons can be calculated in 3 different ways
• 1 Cubic Foot = 7.48 US Gallons
• 1 Cubic Foot = 6.23 Imperial Gallons
• 1 Cubic meter = 264.17 US Gallons
• 1 Cubic meter = 220 Imperial gallons