4 Container Shapes
Rectangular, cylindrical, triangular and oval containers — covering the vast majority of real-world tanks and pools.
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The Fastest Water Volume
Calculator Online
Enter the dimensions of any container — pool, tank, barrel, aquarium or cistern — and get the exact capacity in liters, gallons and cubic meters in under a second.
4
Container shapes
5
Measurement units
8
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Swimming pools
Water tanks
Aquariums
Cisterns
IBC containers
Rainwater collection
Hot tubs & spas
Irrigation tanks
Construction cisterns
Industrial drums
How to Calculate Water Volume
Three simple steps to know exactly how many liters fit in your container.
1
Choose your container shape
Select from rectangular (pools, tanks, boxes), cylindrical (drums, barrels, wells), triangular (prisms, wedge tanks) or oval/elliptical (elliptical pools, capsule tanks).
Rectangular
Cylindrical
Triangular
Oval
2
Enter the dimensions
Input length, width, depth (or diameter and height for cylinders). Pick your preferred measurement unit — meters, centimeters, millimeters, feet or inches. AquaCalc handles all the unit conversion automatically.
m
cm
mm
ft
in
3
Get instant results
Receive your water capacity in multiple units simultaneously: liters, cubic meters, US gallons, UK gallons and weight in kilograms. A visual water-fill bar gives you an intuitive sense of scale.
Liters
m³
US gal
kg
Everything You Need to Calculate Tank Capacity
AquaCalc was built to be the most complete free water volume calculator available — no paywalls, no registration.
5 Measurement Units
Enter dimensions in meters, centimeters, millimeters, feet or inches. The calculator converts automatically before computing.
Multiple Output Units
Results in liters, m³, US gallons, UK gallons and kilograms — all displayed at once without needing extra conversions.
8 Languages
Fully translated into English, Spanish, German, French, Italian, Japanese, Korean and Hindi. Language auto-detected from your browser.
ENES
DEFR
IT日本語
한국어हिंदी
Fully Responsive
Works on any device — phone, tablet or desktop. Optimized for quick field measurements with large tap targets and clear typography.
Instant & Free
No registration, no email, no ads. Open the tool, enter your measurements, get your result. Calculation is instant and client-side.
Water Volume Formulas Explained
AquaCalc uses the standard geometric volume formulas below. All results are converted to liters (1 m³ = 1,000 L).
Rectangular Tank / Pool
Volume (L) = Length × Width × Depth × 1000
The simplest calculation. Used for swimming pools, rectangular cisterns, storage tanks and any box-shaped container. All dimensions must be in the same unit (e.g., meters) before multiplying by 1000 to get liters.
Cylindrical Tank / Barrel
Volume (L) = π × (Diameter / 2)² × Height × 1000
Used for drums, barrels, rain-collection cylinders, water wells and round storage tanks. Enter the total outer diameter and the usable height of the liquid level.
Triangular Prism Tank
Volume (L) = ½ × Base × Triangle Height × Depth × 1000
Useful for V-shaped sumps, wedge-bottomed holding tanks and custom irrigation reservoirs. The base and triangle height refer to the triangular cross-section.
Oval / Elliptical Pool
Volume (L) = π × (A/2) × (B/2) × Depth × 1000
Applies to elliptical swimming pools, oval hot tubs and capsule-shaped tanks. A and B are the two perpendicular axis lengths (length and width of the ellipse).
When Do You Need a Water Volume Calculator?
Knowing the exact capacity of a container is critical for dozens of real-world situations.
Swimming Pool Chemical Dosing
Chlorine, pH correctors and algaecides are all dosed per 1,000 liters. An inaccurate pool volume leads to under-treatment (bacteria risk) or over-treatment (skin and eye irritation).
Rainwater Harvesting Tanks
Before installing a rainwater collection system, you need to know how many liters your storage tank holds to match it to your roof catchment area and consumption needs.
Aquarium Setup & Fish Stocking
Every aquarium medication, water conditioner and fish stocking guide is based on tank volume in liters. Getting this right is essential for the health of your fish.
Agricultural Irrigation Tanks
Farmers and horticulturists need to know irrigation tank capacity to plan fertilizer dilution ratios and ensure enough water is available between fill cycles.
Construction & Civil Engineering
Structural engineers must calculate water tank loads (1 liter = 1 kg) to verify that foundations and slabs can support the weight of a full water storage system.
Hot Tub & Spa Maintenance
Spa chemicals, water balance products and sanitizer quantities all depend on the exact liters in your hot tub. Most manufacturers recommend testing and dosing per 1,000 L.
Available in 8 Languages — Auto-Detected
AquaCalc detects your browser language and switches automatically. Every label, formula hint and result unit is fully translated — not just the UI chrome.
English
Default
Español
Spanish
Deutsch
German
Français
French
Italiano
Italian
日本語
Japanese
한국어
Korean
हिंदी
Hindi
Frequently Asked Questions
Everything you need to know about calculating water volume and capacity.
For a rectangular container, multiply length × width × depth (all in meters) and then multiply by 1,000 to get liters. For example, a tank 2 m long, 1 m wide and 0.5 m deep holds 2 × 1 × 0.5 × 1,000 = 1,000 liters. AquaCalc automates this for rectangular, cylindrical, triangular and oval shapes with any unit of measurement.
Multiply the pool's length × width × average depth (in meters) × 1,000. A typical family pool 8 m × 4 m × 1.5 m deep holds 8 × 4 × 1.5 × 1,000 = 48,000 liters. Always use the actual water depth, not the wall height. Use AquaCalc's rectangular mode for an instant, accurate result.
One cubic meter equals exactly 1,000 liters. To convert, simply multiply m³ × 1,000. For example, 0.5 m³ = 500 liters, 2.75 m³ = 2,750 liters. AquaCalc displays both m³ and liters in every result automatically.
The formula is V = π × r² × h, where r is the radius (diameter ÷ 2) and h is the height. Multiply by 1,000 to get liters. For a 200-liter drum with a 60 cm diameter and 90 cm height: π × (0.30)² × 0.90 × 1,000 ≈ 254 liters. AquaCalc handles this automatically when you select the cylindrical shape.
Water weighs approximately 1 kilogram per liter at room temperature (1 kg/L is the practical standard). So a 10,000-liter swimming pool holds 10,000 kg (10 tonnes) of water, not counting the structure. AquaCalc includes the weight in kg in every result to help with structural load calculations.
Yes. AquaCalc lets you enter dimensions in meters, centimeters, millimeters, feet or inches. It automatically converts all units to meters internally before computing the result, so you never have to do manual unit conversions.
For an oval (elliptical) pool the formula is π × (length/2) × (width/2) × depth × 1,000 = liters. For a 6 m × 3.5 m × 1.4 m deep oval pool: π × 3 × 1.75 × 1.4 × 1,000 ≈ 23,091 liters. Select the Oval shape in AquaCalc and enter the two axis lengths and depth.
Volume is the three-dimensional space a container occupies or encloses, measured in m³ or ft³. Capacity is the amount of liquid the container can hold, typically expressed in liters or gallons. In practice they are equivalent — 1 m³ of internal volume can hold 1,000 liters of water. AquaCalc calculates both simultaneously.
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