Enter diameter, cylinder height and cone height — units can differ per field
Cylindrical section
Diameter
Cyl. Height
Cone Height
Fill Level
100%
25%50%75%Full
⚠ Please enter valid numbers (greater than zero) for all three dimensions.
WaterTankCalculator.com — Cone Bottom Tank Results
Your Results
Total Volume
—
Litres (L)
Cylinder Volume
— L
Cone Volume
— L
Cubic Metres
— m³
US Gallons
— gal
UK/Imperial Gallons
— gal
Cubic Feet
— ft³
Cubic Inches
— in³
Water Weight
— kg
Weight (lbs)
— lbs
Fill Level
— %
Visual Fill Level
📖 How To Use
How to Use This Cone Bottom Tank Volume Calculator
Calculating the total capacity of a cone bottom tank takes under 60 seconds — just measure three dimensions:
Measure the internal diameter
Use the inside diameter of the cylindrical section. External diameter overstates internal volume by the wall thickness on both sides — typically 6–20 mm (¼–¾ in) in total for polyethylene or stainless steel tanks.
Measure the cylinder height
This is the straight vertical wall height of the cylindrical section only — from the top of the cone joint up to the top of the tank body. Do not include the cone depth in this measurement.
Measure the cone height
The vertical depth of the conical section from the base of the cylinder down to the outlet tip. On a 45° cone, this equals the cone's base radius. On steeper cones, it will be greater.
Choose your units per field
Each input has its own unit selector — ft, in, cm, m, or mm. Mix units freely if needed (e.g., diameter in inches, heights in cm).
Adjust the fill level slider (optional)
Set to less than 100% to calculate volume at a partial fill — useful for monitoring current inventory or planning headspace. The percentage is of the total volume; the cone fills first, and the note under the results shows how deep the liquid stands at that level.
Hit Calculate
Results appear instantly: total litres, breakdown by cylinder and cone, US/UK gallons, cubic metres, water weight, and more.
Tip: The cone section always holds less than you expect. A cone holds exactly one-third of a cylinder with the same diameter and height. On most tanks the cone is only about 10–20% of the total capacity; it reaches 25% only when the cone is as tall as the straight wall.
📐 The Formula
Cone Bottom Tank Volume Formula
A cone bottom tank is calculated as two separate geometric shapes — a cylinder on top and a cone below — added together:
Where r = Diameter ÷ 2
Litres (cm inputs): divide cm³ result by 1,000
US gallons (ft inputs): ft³ × 7.48
This calculator converts all inputs to centimetres first, computes both volumes, then applies the fill percentage — filling the cone first, then the cylinder — and converts to all output units. For a partly filled tank, the liquid depth in the cone is h = Hcone × (V ÷ Vcone)1/3, because a cone's volume grows with the cube of its depth.
Unit Conversion Reference
Unit
Equals Litres
From Litres
1 Litre (L)
1 L
× 1
1 Cubic Metre (m³)
1,000 L
÷ 1,000
1 US Gallon
3.785 L
÷ 3.785
1 UK Gallon
4.546 L
÷ 4.546
1 Cubic Foot (ft³)
28.317 L
÷ 28.317
1 Cubic Inch (in³)
0.01639 L
× 61.024
Water Weight
1 litre of fresh water weighs about 1 kg (2.2046 lb), and 1 US gallon about 8.34 lb. The exact figure is 0.998 kg per litre at 20 °C (68 °F), so 1 kg per litre is the standard rounding used for load estimates. In US units, 1 cubic foot = 7.48 US gallons and 1 US gallon = 231 cubic inches.
Typical cone bottom tank proportions and their calculated total volumes. In these examples the cone height equals the radius — a 45° cone:
Diameter
Cyl. Height
Cone Height
Total Litres
US Gal
Full Weight
60 cm
80 cm
30 cm
254
67
254 kg
80 cm
100 cm
40 cm
570
150
570 kg
100 cm
120 cm
50 cm
1,073
284
1,073 kg
120 cm
150 cm
60 cm
1,923
508
1,923 kg
150 cm
180 cm
75 cm
3,623
957
3,623 kg
180 cm
220 cm
90 cm
6,362
1,681
6,362 kg
200 cm
250 cm
100 cm
8,901
2,351
8,901 kg
Note: Actual manufacturer dimensions vary. Always verify against the supplier's data sheet and measure internal dimensions.
Cone Angle and Its Effect on Volume
Cone Slope (from horizontal)
Cone Height (for 100 cm / 39.4 in diameter)
Cone Volume
Notes
60°
86.6 cm (34.1 in)
227 L (60 gal)
Very steep — drains fully, even sludge and solids
45°
50 cm (19.7 in)
131 L (35 gal)
Common choice for full drainage
30°
28.9 cm (11.4 in)
76 L (20 gal)
Shallower — drains liquids well
15°
13.4 cm (5.3 in)
35 L (9 gal)
Gentle slope — helps the last of the liquid reach the outlet
Cone height = radius × tan(slope). Makers usually quote the slope measured from horizontal, as here; a few quote the angle from vertical or the full angle at the tip, so check which one a data sheet means before you work out the height.
🏭 Use Cases
When to Use a Cone Bottom Tank Volume Calculator
Cone bottom tanks (also called hopper bottom tanks or conical tanks) appear across many industries wherever complete drainage or solids collection is needed. This calculator is the right tool whenever you need to:
🧪
Chemical Processing
Dose chemicals accurately from batch tanks. Knowing exact volume means precise concentration calculations.
🍺
Brewing & Fermentation
Conical fermenters use the bottom cone to collect yeast. Total volume determines batch yield.
💧
Water Treatment
Settling and clarifier cones require accurate volume for dosing coagulants and sizing pumps.
🌾
Agriculture & Feed
Hopper-bottom grain bins and liquid fertiliser tanks need capacity figures for stock management.
💊
Pharmaceuticals
Sterile process vessels with conical bottoms require validated volume data for batch records.
🛢️
Liquid Storage
Juice, dairy, oil, and other food-grade liquids are stored in conical tanks to ensure zero residue.
🧮 Worked Example
Worked example: a 4 ft cone bottom tank, half full
A cone bottom tank is 4 ft (1.22 m) across inside, with 5 ft (1.52 m) of straight wall and a 45° cone 2 ft (0.61 m) deep.
Cylinder: π × 2² × 5 = 62.83 ft³.
Cone: ⅓ × π × 2² × 2 = 8.38 ft³ — about 12% of the total.
Half full (266 gallons): the cone's 63 gallons fill first, so the liquid stands about 4.2 ft above the tip of the cone — well over half the 7 ft total height.
That last point is why a sight-tube or dipstick reading on a cone tank can't be turned into gallons by a simple percentage of the height.
❓ FAQ
Frequently Asked Questions
How do I calculate the volume of a cone bottom tank?
A cone bottom tank has two parts: a cylinder on top and a cone below. Calculate each separately and add the results. Cylinder volume = π × r² × h. Cone volume = (1/3) × π × r² × h_cone. This calculator handles all the math and unit conversions automatically — just enter diameter, cylinder height, and cone height.
What is a cone bottom tank used for?
Cone bottom tanks are used wherever complete drainage or solids settling is needed. Common applications include fermentation (collecting yeast), chemical dosing, water treatment (settling solids), food processing, pharmaceuticals, and agricultural liquid storage. The sloped cone ensures nothing is left behind when emptying.
What is the difference between cone height and total tank height?
Total tank height = cylinder height + cone height. The cylinder height is only the straight-wall section from the top of the cone joint to the top of the body. The cone height is the vertical depth of the tapered section alone. Enter them separately into this calculator — they are calculated with different formulas (cylinder vs. cone geometry).
How much volume does the cone section hold compared to the cylinder?
For the same base diameter and height, a cone holds exactly one-third (33.3%) of a cylinder's volume. In practice, because tank cone heights are typically 30–60% of cylinder heights, the cone section represents roughly 9–17% of total tank capacity. The calculator shows both values separately so you can see the breakdown clearly.
Should I use internal or external dimensions for cone bottom tank volume?
Always use internal dimensions. External diameter includes wall thickness on both sides — typically 5–15 mm each side for polyethylene, and up to 10 mm per side for stainless steel. For a 60 cm (23.6 in) external diameter tank with 8 mm walls, the internal diameter is 58.4 cm — a 2.7% difference in diameter, which becomes about a 5% difference in volume because volume goes with the diameter squared.
How do I measure the cone height if I can't access the bottom?
If you know the cone's slope, you can work out the height from the radius. Makers usually quote the slope from horizontal: Cone Height = r × tan(slope). A 45° cone's height equals its radius (half the diameter); a 30° cone is 0.577 × r, a 60° cone 1.732 × r, and a 15° cone 0.268 × r. If the data sheet gives the angle at the tip instead, Cone Height = r ÷ tan(half the tip angle) — a 90° tip is the same as a 45° slope. Check which convention the manufacturer uses.
Can this calculator handle metric and imperial units at the same time?
Yes. Each dimension field has its own independent unit selector. You can enter diameter in inches, cylinder height in feet, and cone height in centimetres all in the same calculation. The calculator converts everything to centimetres internally before computing volumes, ensuring correct results regardless of the mix of units used.
What is the weight of a full cone bottom tank?
Fresh water weighs about 1 kg per litre, or 8.34 lb per US gallon. A full 1,000-litre (264-gallon) cone bottom tank holds about 1,000 kg (2,200 lb) of water plus the tank shell (typically 40–100 kg depending on material and size) and its stand. For industrial tanks on raised frames or mezzanines, always have a structural engineer verify the load rating. Use our Water Tank Weight Calculator for precise structural load figures.
✅ Sources & Review
Sources and review
The formulas are standard geometry; the conversion factors and figures on this page come from these references:
USGS Water Science School — Water Density: about 1 kg per litre (62.4 lb/ft³, 8.34 lb per US gallon).
Reviewed by John Mac, PE, Water Systems Specialist
Texas-licensed Professional Engineer with 13+ years in residential water storage and 180+ tank projects. John writes and reviews every calculator on this site.
