Tank volume FAQ

Total volume is πr²L (radius squared × pi × length). For a partly filled tank the liquid forms a circular segment, so you need the segment area × length — our horizontal cylinder calculator does it exactly, and the formula page shows the full derivation.

V(h) = [r²·acos((r−h)/r) − (r−h)·√(2rh−h²)] × L, where h is liquid depth. It’s the circular-segment area times the length — closed-form, spreadsheet-friendly, and explained on the horizontal cylinder formula page.

Be careful which “oval” you have: a true ellipse uses πab×L (our oval calculator), but most home heating-oil tanks are actually obround — flat sides with semicircular ends — which needs different piecewise math on the heating oil tank calculator.

Yes — the cone-bottom calculator handles the conical section (volume grows with the cube of depth there) plus the cylindrical body, in gallons or litres. At 40% depth a typical cone tank holds only about 26% of its volume.

An ellipse is a circle scaled horizontally, so the area is π×a×b and a partial fill is (a/b) times the equivalent circular segment — exact, no approximation. See the elliptical formula page or run it on the oval calculator.

Full sphere is (4/3)πr³; a partial fill uses the spherical-cap formula πh²(3r−h)/3. It’s strongly nonlinear — exactly half the sphere at half depth, but only ~15.6% at quarter depth. The sphere calculator handles both.

Yes — the frustum calculator uses πH(R²+Rr+r²)/3 for the full tank and interpolates the wetted radius for partial fills, covering buckets, hoppers and tapered vats.

An ASME torispherical (F&D) head has no tidy closed form, so we scale the spherical cap by an effective depth (0.1545×D) matched to the standard head volume — worst-case error under 0.06% of a 500-gallon vessel. Details and the error bounds are published; use the propane calculator for dished-head vessels.

A pipe is a horizontal cylinder on its inside diameter: V = π(ID/2)²×L. The pipe volume calculator gives gallons and water weight per length; use the nominal vs actual ID carefully, since schedule changes the bore.

A round stock tank is a vertical cylinder: gallons per inch of depth = π(D/2)² ÷ 231. A 10-ft-diameter tank holds about 587 gallons per foot of depth. Enter your diameter on the vertical cylinder calculator, or print a chart with the dip chart generator.

Yes — volume is L×W×H ÷ 231 for gallons (or ÷1000 for litres from centimetres). The rectangular calculator handles totes, sumps and aquariums at any fill level.

A hemisphere is half a sphere: (2/3)πr³. A capsule (cylinder with two hemispherical ends) combines a cylinder with one full sphere of heads — see the capsule formula or the sphere calculator for the cap math.

Add the cylindrical shell (a circular segment × length) to the two dished heads. Ellipsoidal 2:1 heads scale the spherical cap by ½; ASME F&D heads are shallower. The propane calculator models F&D heads; the formula page shows the method.

It’s the easy one: every slice is the same circle, so volume is exactly linear — πr²h, with a constant gallons-per-inch of πr²÷231. The vertical cylinder calculator covers it.

A sloped or coned bottom holds less near the floor than a flat one. For a conical bottom use the cone-bottom calculator; for a slight slope, approximate with the cone section depth. The key point is that the bottom portion is never linear — don’t use flat-tank gallons-per-inch there.

Enter your tank’s dimensions and shape in the dip chart generator, pick a step (1″, ½″, 1 cm or 5 cm), and download a laminate-ready PDF converting every depth to volume — with your dimensions printed on each page for field verification.

Yes, but the conversion isn’t linear — the middle inches hold the most. Use a per-tank chart or generate one for your exact size; for straight-walled tanks the gallons-per-inch calculator gives the constant.

The 275 vertical and 275 horizontal chart pages have full inch-by-inch tables and printable PDFs — cross-checked against the Highland Tank gauge book.

Gallons of propane = gauge percent × water capacity. A 500-gallon tank at 38% holds 190 gallons. Remember the gauge reads percent of water capacity and “full” is 80% — the 500 propane chart has the table.

Stick the tank to the bottom, read the wet line, and convert with the chart for your tank’s size and orientation. The 1000-gallon chart covers the common underground cylinder; print it for the field.

For a vertical 48-inch-diameter tank it’s a constant 7.83 gallons per inch (π×24²÷231). For a horizontal 4-foot tank it varies with depth — most at the centerline, least near top and bottom — so use a chart. Try the gallons-per-inch calculator.

Yes — the dip chart generator produces a calibrated strapping chart for any tank from exact geometry, the same math verified against manufacturer gauge books.

Lower a clean stick straight down to the tank bottom, hold it vertical, lift it out and read the wet/dry line — that depth converts to gallons on your chart. The full technique, including water-finding paste, is in the stick method guide.

A strapping (dip) chart tabulates volume at each depth increment using the tank’s exact partial-fill geometry — circular segments for round tanks, piecewise math for obround. Our methodology page documents every formula; the generator builds the chart.

Yes — every calculator here takes a liquid depth and returns volume for the matching shape. Start at the universal calculator, pick your tank, and move the depth slider or type the stick reading.

A standard 275 is an obround tank about 27″ wide × 44″ tall × 60″ long (vertical orientation), holding ~267.9 gallons brim-full and filled to ~250. Full specs and weight are on the 275 dimensions page.

If “10 foot” is the diameter, a round stock tank holds about 587 gallons per foot of water depth (π×5²×7.48). A 2-foot-deep fill is ~1,175 gallons. Enter your exact diameter and depth on the vertical cylinder calculator.

A 500-gallon ASME propane tank is about 37.5″ in diameter and ~10 feet long overall including the dished heads. Dimensions, weights and NFPA 58 clearances are on the 500 propane page.

A 3×3×3-foot cube is 27 cubic feet × 7.48 = about 202 gallons. For exact figures on any box dimensions use the rectangular calculator.

Standard IBC totes are 275 and 330 gallons. The bottle is roughly rectangular with rounded corners, so use the molded markings near the bottom and the 275 / 330 tote charts for in-between depths.

Standard rectangular frac (frac/storage) tanks typically hold around 21,000 gallons (500 barrels); a “20K” unit is about 20,000 gallons. Because models vary by manufacturer, confirm against the nameplate — then verify any depth with the rectangular calculator.

About 1,337 cubic feet — for example a vertical cylinder roughly 12 ft in diameter and 12 ft tall, or 10 ft diameter × 17 ft. Manufacturers vary the proportions; the sizes library and calculator let you check any combination.

Common diesel storage runs 100, 250, 500, 1000 gallons and up; transfer tanks are 50–100 gallons. See the tank sizes library for dimensions and the diesel weight page for load planning (500 gallons ≈ 3,525 lb).

In the US, size by bedrooms — 1,000 gallons is the typical 3-bedroom minimum; in India, by users under IS 2470. The septic calculator covers both, but your local health authority’s code governs the final number.

Common steel USTs use 48″ or 64″ diameters: a 64″×108″ holds ~1,500 gallons, 64″×144″ ~2,000. Dimensions and charts for the standard sizes are in the sizes and charts libraries.

About 3,525 lb (at ~7.05 lb/gal; the 7.0–7.1 grade range puts it at 3,500–3,550). In a typical skid tank that’s 4,200–4,700 lb gross — beyond a half-ton pickup’s payload. Full breakdown on the 500 gallons of diesel page.

Yes — the thermal expansion calculator computes ΔV = V×β×ΔT with sourced coefficients (diesel 0.00046/°F per Chevron), tells you whether your ullage absorbs the swing, and gives the max safe temperature.

Enough to absorb thermal expansion plus a working margin: heating oil tanks fill to ~90% (a 275 to ~250 gal), and codes/suppliers set the practice. The thermal calculator shows the physics; see also what ullage is. Codes govern over the bare math.

UAN 32% is about 11.06 lb/gal and UAN 28% about 10.65 — so a 275-gallon tote of UAN 32 is over 3,000 lb. Cited figures and a calculator are on the UAN weight page.

Vapor (ullage) space is tank capacity minus liquid volume; for crude, overfill protection follows API 2350, which reserves more than thermal expansion alone requires. Crude density varies widely by grade (6.6–8.1 lb/gal), so we don’t publish a single value — use measured gravity. The thermal/ullage tool covers the expansion math.

Ullage is the empty distance from a top reference down to the surface; sounding (innage) is the liquid depth from the bottom. They sum to the reference height. Every calculator here reports both — see the ullage guide.

Weight = volume × (specific gravity × 8.345 lb/gal). The weight library lists cited densities and gives gallons→pounds/kilograms for 15 liquids; multiply SG by 8.345 for any other fluid.

The thermal expansion tool shows the physics-based fill room and always reports the larger of expansion and a 5% working margin. It’s a screening estimate only — chemical and pressure-tank fill limits are set by codes (NFPA, OSHA, API) that govern over any calculator.

The water alone is about 8,345 lb (1,000 gal × 8.345) — over four tons — plus the tank. Design the slab or stand for it; see the water weight page.

Liquid propane expands far more than fuels — roughly 15× water per degree — which is exactly why NFPA 58 caps the fill at 80% and the float gauge is calibrated to it. You don’t compute LPG ullage yourself; the 80% rule is the answer. Background is on the thermal expansion page.