Exact volume for any tank, at any fill level.
Most tools only compute a full tank. This calculator solves the partial-fill problem with exact closed-form geometry — circular segments, ellipse sections, obround oil-tank profiles and dished propane heads — so the gallons at your dipstick reading are right, not approximated.
Exact segment geometry — see methodology. Dished-head propane math is documented there too.
One calculator per geometry, built deep.
SEC. 02 / SHAPE LIBRARYHorizontal Cylinder
Fuel, oil & water tanks lying on their side. Circular-segment partial fill.
TVC-102Vertical Cylinder
Standing water & chemical tanks. Linear gallons-per-inch.
TVC-103Rectangular Tank
Aquariums, sumps, totes and transfer tanks.
OBROUNDTVC-104Heating Oil Tank
True obround 275/330 profile — not an ellipse approximation.
80% RULETVC-105Propane Tank
ASME vessels with dished heads, gauge % and fill limits.
TVC-106Oval / Elliptical
True-ellipse horizontal tanks. Exact ellipse-section math.
TVC-112Dished Bottom
Vertical tanks on 2:1 ellipsoidal heads. Exact head math.
TVC-107Cone-Bottom
Industrial mixing & settling tanks with conical outlets.
TVC-108Sphere
Spherical vessels & floats. Spherical-cap fill volume.
TVC-109Frustum / Tapered
Buckets, hoppers and tapered vats.
POPULARTVC-110Pipe Volume
Volume & liquid weight per length of pipe, any diameter.
TVC-111Fill Time
How long to fill or drain a tank at a given GPM.
SAFETY MATHTVC-401Thermal Expansion
Ullage check, max safe temp, the math behind fill rules.
FIELD TOOLTVC-301Dip Chart Generator
Laminate-ready strapping chart for any tank, any dimensions.
Tank charts you can actually read.
SEC. 03 / DIP CHART LIBRARYInch-by-inch gallon tables for every standard tank — interactive on screen, printable as a clean one-page PDF for the boiler room wall.
Questions people ask.
SEC. 04 / FAQHow do I calculate how many gallons are in my tank?
Measure the liquid depth with a stick, pick your tank shape above, enter the tank dimensions, and set the fill slider to your reading. The calculator returns gallons, liters and percent full using exact partial-fill geometry — or use a pre-built tank chart for standard tanks.
Why is partial-fill volume hard for round tanks?
In a horizontal cylinder the middle inches hold far more liquid than the top and bottom inches, so volume is not proportional to depth. This calculator solves the circular-segment area exactly instead of approximating.
Does this work for metric tanks?
Yes. Switch the dimension unit to centimeters or meters; results show gallons and liters side by side.
Is my data stored anywhere?
No. All math runs locally in your browser. Nothing you type is transmitted or stored.