Horizontal Cylinder Volume Calculator
Horizontal cylinder liquid volume uses V = segment area times length. For a horizontal tank with radius 1 m, length 5 m, and fill depth 1 m (half-full), liquid volume is 7.854 m3, or 7,853.98 litres (2,074.80 US gallons). Enter your horizontal tank dimensions and dipstick depth below to calculate volume.
Calculator
Horizontal tank orientation
Partially filled horizontal tank geometry
This tool computes liquid volume in sideways cylinders. Because surface width changes with depth, partial volume uses circular segment math.
Circular segment formulas for horizontal vessels
To find partial volume, calculate the circular segment area and multiply by tank length. Enter your tank size and dipstick depth below.
Frequently Asked Questions
Why is horizontal volume so hard to calculate manually?
Because the tank's circular face is turned sideways, the liquid is filling against a curve. The width of the fluid surface gets wider at the middle, and narrower at the top, making the math entirely non-linear.
How do you calculate horizontal cylinder volume at 100% full?
If the tank is entirely 100% full to the brim, the math is simple. Just use the standard formula: Volume = Pi × radius² × length.
What is the formula for a partially filled horizontal cylinder?
The core formula requires finding the area of the circular fluid segment first: Area = r² × arccos((r-h)/r) - (r-h) × √(2rh - h²). You then multiply that segment Area by the total Length.
What kind of tanks are normally horizontal?
Standard propane tanks, home heating oil reservoirs, massive underground gas station reservoirs, and 18-wheeler liquid transport trucks are almost universally horizontal cylinders.
Can I use standard dipstick 'inches' to find horizontal gallons?
Yes. Our tool is designed exactly for that. Measure the wet depth of the liquid on your dipstick in inches, enter it as the 'Fill Height', and we will convert the complex curve into accurate gallons.
How do you calculate the volume of a partially filled horizontal cylinder?
For a horizontal partially filled cylinder (such as a fuel or water tank on its side), the formula calculates the circular segment area multiplied by the length: V = L × [r² × arccos((r − d) / r) − (r − d) × √(2rd − d²)], where L is the cylinder length, r is the radius, and d is the liquid depth measured from the bottom. A horizontal cylinder is less than half full when d < r and more than half full when d > r.