Pool Volume Calculator
Gallons and litres for rectangular or round pools.
Lumber & Materials
Tank Volume Calculator
Choose your tank shape and enter its dimensions and liquid depth to see its total capacity and how much it holds now. Works for vertical, horizontal, rectangular and oval tanks.
Your result
Sample values940
Gallons total
125.7
Cubic feet
3,558
Litres total
752
Gallons at current fill
Horizontal cylinder, 4 ft by 10 ft, filled to 30 in.
Fill reference
| Depth | Volume |
|---|---|
| 12 in | 246 gal |
| 24 in | 564 gal |
| 30 in | 752 gal |
| 36 in | 875 gal |
| 48 in — full | 940 gal |
Tank Volume Calculator: Calculate Capacity and Liquid Volume
Knowing how much a tank can hold is essential when storing water, fuel, chemicals, or other liquids. The deep4sol tank volume calculator helps you estimate total tank capacity, the amount of liquid currently inside, the space still available, and the percentage filled. It supports horizontal, vertical, rectangular, and oval tanks, making it useful for household water storage, construction projects, agriculture, and industrial planning.
Use it as a water tank volume calculator or for checking other stored liquids.
What Is a Tank Volume Calculator?
A tank volume calculator is a measurement tool that determines the internal space of a container using its dimensions and geometry.
Tank capacity means the tank’s total internal volume. Liquid volume means the amount it contains at the measured depth. Remaining capacity is the difference between these values, while fill percentage expresses how full the tank is.
Unlike a simple length-times-width calculation, tank calculations must account for shape. For example, liquid in a horizontal cylinder does not increase at a constant rate as the depth rises.
Tank Shapes Supported by the Calculator
Vertical Cylindrical Tanks
Vertical tanks stand upright with a circular base. They are common in domestic water systems, rainwater collection, farming, and commercial storage. Diameter and internal height determine their total capacity. Because the cross-sectional area remains constant from bottom to top, a liquid level halfway up a straight-sided vertical cylinder represents approximately 50% of its capacity.
Horizontal Cylindrical Tanks
Horizontal tanks rest on their sides and are used for water, fuel, and other liquids. Their length and diameter determine full capacity, but calculating the liquid inside requires a circular-segment formula. At one-quarter of the tank’s diameter, the liquid occupies less than one-quarter of its full volume.
Rectangular Tanks
Rectangular tanks include box-shaped reservoirs, sumps, and some water storage containers. Length, width, and height determine total volume. For straight walls and a flat bottom, multiplying the base area by liquid depth gives the current liquid volume. This makes rectangular tanks relatively straightforward to measure.
Oval Tanks
An oval tank has a noncircular cross-section. Some oval tanks follow a true ellipse, while others have straight sections joined by curved ends. Their capacity depends on the exact profile, dimensions, and orientation. Use the actual tank profile; a manufacturer’s capacity chart may be more accurate for irregular shapes.
Tank Volume Calculator Inputs and Outputs
Enter the dimensions applicable to your tank shape.
| Input | What It Represents |
|---|---|
| Tank Shape | Horizontal, vertical, rectangular, or oval |
| Diameter | Width across a circular tank |
| Length | End-to-end tank dimension |
| Width | Side-to-side dimension for relevant shapes |
| Height | Overall vertical dimension |
| Liquid Depth | Vertical distance from the inside bottom to the liquid surface |
| Wall Thickness | Material thickness used to adjust external measurements when applicable |
The calculator provides four results:
- Total capacity
- Current liquid volume
- Remaining capacity
- Fill percentage
How to Use the Tank Volume Calculator
- Select the tank shape. Identify whether the tank is upright, horizontal, rectangular, or oval.
- Measure its dimensions. Use the diameter, length, width, or height relevant to that shape. Check whether your measurements are internal or external.
- Enter the liquid depth. Measure vertically from the tank’s inside bottom to the liquid surface, with the tank level.
- Include wall thickness if applicable. This helps distinguish outside dimensions from the smaller internal space that actually holds liquid.
- Review the results. Compare total capacity, current volume, available space, and fill percentage.
Keep all dimensions in the same length unit before calculating volume of tank storage. For instance, do not combine centimeters and meters without converting one of them first.
Tank Volume Calculation Formulas
The right equation depends on shape and orientation. In the formulas below, use internal dimensions and consistent units; the result will be in cubic units.
Vertical Cylinder
For an upright circular tank:
Total Volume:
V = π × r² × H
Liquid Volume:
V = π × r² × h
- r = Internal radius (diameter divided by two)
- H = Internal tank height
- h = Liquid depth
Rectangular Tank
For a box-shaped tank with vertical walls:
Total Volume:
V = L × W × H
Liquid Volume:
V = L × W × h
- L = Internal length
- W = Internal width
- H = Internal height
- h = Liquid depth
Horizontal Cylinder
A partly filled horizontal cylinder uses the area of a circular segment.
Liquid Volume:
V = L × [r² × arccos((r − h) ÷ r) − (r − h) × √(2rh − h²)]
- L = Internal tank length
- r = Internal radius
- h = Liquid depth, from 0 to 2r
The inverse cosine is expressed in radians. For full capacity:
V = π × r² × L
Elliptical Oval Tank
If the tank has a true elliptical cross-section and a uniform length, its full volume is:
V = π × a × b × L
- a = Internal horizontal semi-axis
- b = Internal vertical semi-axis
- L = Internal length
Partially filled oval tanks require a depth-based calculation appropriate to the profile. A stadium-shaped or rounded-rectangle tank needs a different formula.
For all shapes:
Remaining Capacity = Total Capacity − Current Liquid Volume
Fill Percentage = (Current Liquid Volume ÷ Total Capacity) × 100
These equations describe geometric storage volume, not the maximum safe operating fill level.
Practical Example: Calculating Water Tank Capacity
Suppose you have a vertical cylindrical water tank with these internal measurements:
- Diameter: 2 m
- Height: 3 m
- Current water depth: 1.2 m
First, divide the diameter by two to obtain a radius of 1 m.
Total Capacity
3.1416 × 1² × 3 = 9.425 m³
Current Water Volume
3.1416 × 1² × 1.2 = 3.770 m³
Remaining Capacity
9.425 − 3.770 = 5.655 m³
Fill Percentage
(3.770 ÷ 9.425) × 100 ≈ 40%
Since one cubic meter equals 1,000 liters, the tank holds approximately 9,425 liters when full and currently contains 3,770 liters. About 5,655 liters of geometric capacity remains, assuming a flat bottom and no internal obstructions.
This shows how to calculate tank volume for an upright water tank. Horizontal tanks require a different formula.
Tank Volume Unit Conversions
Tank measurements may use millimeters, centimeters, meters, inches, or feet. Convert all dimensions to the same unit before applying a formula.
| Volume Measurement | Equivalent |
|---|---|
| 1 cubic meter (m³) | 1,000 liters |
| 1 liter (L) | 1,000 cubic centimeters |
| 1 cubic foot (ft³) | About 28.317 liters |
| 1 U.S. gallon | About 3.785 liters |
| 1 Imperial gallon | 4.54609 liters |
U.S. and Imperial gallons are different, so confirm which one is required. See NIST conversion factors for standard measurement relationships.
Why Calculate Tank Capacity and Liquid Level?
A reliable calculator for tank volume supports everyday and technical decisions. It can help you:
- Estimate stored water for households, irrigation, or livestock.
- Check available space before scheduling a tank refill or liquid delivery.
- Compare tank sizes during construction or equipment selection.
- Monitor approximate liquid inventory in workshop or industrial storage.
- Plan overflow protection and maintain a suitable operational margin.
For regulated transfers or precision inventory, use calibrated instruments.
Accuracy Factors to Check
Internal versus External Dimensions
A tank’s labeled outside size includes its walls. If dimensions were measured externally and wall thickness is uniform, the internal diameter or width is generally reduced by twice the wall thickness. Adjust length or height only for the walls or end closures actually included in that measurement.
Tank Ends and Fittings
Domed heads, rounded corners, slopes, baffles, and internal pipes change usable volume. Standard cylinder and box formulas assume ideal shapes.
Liquid-Depth Measurement
Read the depth vertically with the tank level. Tilt, sediment, and an uneven bottom can distort results.
Operating Headspace
A nominally full tank may still require freeboard or expansion space. The geometric volume should not automatically be treated as the approved working capacity.
For critical measurements, compare the estimate with the manufacturer’s specifications or a calibrated tank chart.
Common Mistakes to Avoid
Mixing Units
Entering a width in centimeters alongside a length in meters can produce a major error.
Using Outside Dimensions as Inside Dimensions
This overestimates the space available to liquid.
Treating Depth Percentage as Volume Percentage
This works for straight-sided vertical tanks, not partially filled horizontal cylinders.
Measuring Liquid Depth at an Angle
The formula requires a vertical depth from the internal bottom.
Assuming Every Oval Tank Is Elliptical
Actual construction may require a different cross-sectional formula.
Ignoring Unusable Space
Sediment, fittings, and operating limits can reduce practical storage capacity.
Verify dimensions and geometry before entering values. The deep4sol tank volume calculator estimates capacity, liquid contents, remaining space, and fill percentage for practical planning.
Questions
Frequently Asked Questions
Measure the tank’s internal dimensions and apply the formula for its shape. If the result is in cubic meters, multiply by 1,000 to convert it into liters.
Yes. Use the tank’s internal diameter, length, and measured liquid depth. A circular-segment formula calculates the liquid volume because water depth and volume do not increase proportionally.
Wall thickness reduces the internal dimensions and available storage volume. When using external measurements, account for the sidewalls and tank ends before calculating capacity.
Subtract the current liquid volume from the tank’s total internal capacity. The result represents the empty geometric space, which may be greater than the permitted operating headspace.
Oval tanks may have elliptical, rounded-rectangle, or other cross-sectional profiles. Rounded ends, internal fittings, and measurement errors can affect results, so check the manufacturer’s capacity chart.
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