🛢️Tank Calculator
The Tank Calculator Toolset

Tank Calculators, One Engine

20 tools covering the tank jobs you actually do: capacity and fill for sizing and ordering, dip charts for the gauge stick, head geometry for real vessels, weight for stands and trucks — plus drain and fill times, fish stocking limits, substrate coverage, compressed-air receiver sizing and wall-pressure forces. Every calculator reads the same tank model — the same shapes, the same head formulas, the same densities — so the numbers can never quietly disagree with each other.

Open the Volume Calculator Browse by Category
Free, no sign-up Live on every keystroke Imperial & metric
Industrial storage tanks and vessels at a process plantOne toolset for the whole life of a tankPhoto: Unsplash
Live on every keystroke
Imperial & metric
10 tank shapes
Dip chart generator
No sign-up, no caps
Browse by Job

The Calculators, Categorized

Three groups, ordered the way a tank job unfolds — capacity first, then the geometry corrections that match real vessels, then what the contents weigh. Each card opens the live tool; each category intro explains when its tools are the right ones to reach for.

01

Capacity & Fill

This is where every tank question starts — how much fits. The water tank and fish tank calculators cover the most common specialized geometries, each with worked examples and real-world fill rules. Every calculator listed here returns total capacity and filled volume in US gallons, liters, and cubic feet in a single keystroke.

Reach for these when…

  • You need the total capacity of a round or rectangular tank
  • An aquarium's usable gallons after glass-wall correction
  • A dipstick reading has to become gallons or liters
  • A delivery order needs a reliable usable-volume figure
💧

Water Tank Capacity Calculator

Calculate water tank capacity in liters and gallons for round, rectangular and square tanks — surface area, weight when full, and standard sizes from 200 to 5000L.

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🐠

Fish Tank Volume Calculator

Calculate fish tank volume in gallons and liters for rectangular, cylindrical, oval and hexagon aquariums — with glass wall thickness correction and standard sizes chart.

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🔻

Cone Bottom Tank Volume Calculator

Cone bottom tank volume — frustum hopper plus cylindrical shell, liquid level volume, cone angle and sloped-bottom tanks, with an Excel formula guide.

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📦

Rectangular Tank Volume Calculator

Calculate rectangular and square tank volume in gallons and liters — surface area, glass wall thickness correction, IBC tote sizes, fill weight and dip chart for any box-shaped vessel.

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02

Geometry & Corrections

Real tanks are not simplified cylinders with flat plates on the ends. The horizontal cylinder calculator accounts for dished-end head geometry that hand formulas ignore — hemispherical, 2:1 elliptical and torispherical heads each add a different volume to the shell, and the calculator reports that contribution separately so you can see what the ends are worth.

Reach for these when…

  • Your vessel has curved, dished or elliptical heads
  • You need the shell volume separate from the head volume
  • A horizontal cylinder needs a dip chart
  • You are sizing a bullet tank, road tanker, or frac tank
🛢️

Horizontal Cylinder Tank Volume Calculator

Calculate horizontal cylinder tank volume with flat, hemispherical, or 2:1 elliptical heads — partial fill curve, oval and rectangle cross-sections, standard sizes 100-5000 gal.

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🪙

Vertical Cylinder Tank Volume Calculator

Calculate vertical cylinder tank volume with flat or dished heads — gallons per inch dip chart, standard water tank sizes, surface area and fill weight for upright cylindrical vessels.

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⚽

Sphere & Capsule Tank Volume Calculator

Calculate pure sphere and capsule (cylinder with hemispherical heads) tank volume — partial fill curves, head volume breakdown, LPG and pressure vessel sizes.

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03

Contents & Weight

Volume answers how much fits; weight answers what it loads. The propane tank and diesel fuel calculators specialize in density-sensitive liquids — propane at 0.51× water weight with a legal 80% fill rule, diesel at SG 0.84 running 7.0 lb/gal. The weight figure is what stands, pads, trailer floors and forklift plans actually need.

Reach for these when…

  • Propane sizing from BTU demand with 80% fill rule
  • Diesel fuel tank weight for truck road-weight limits
  • Heating oil usable capacity vs. nameplate
  • Delivery top-up math from a dip chart reading
🔥

Propane Tank Size Calculator

Size a propane tank from BTU demand, check 80% fill rule capacity, and convert propane volume to weight — with standard tank sizes from 20lb to 1000 gal.

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⛽

Diesel & Fuel Tank Calculator

Calculate diesel and fuel tank capacity, weight at any fill level, dip chart for horizontal oval tanks, and delivery top-up math — with standard truck and generator sizes.

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🛢️

Heating Oil Tank Size Calculator

Heating oil tank size calculator — 275-gal oval case study, usable capacity vs nameplate, dip chart for oval tanks, standard sizes 150-550 gal.

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04

Aquarium Stocking & Setup

Two aquarium questions sit outside geometry: how many fish the tank can hold, and how much substrate the bottom needs. The stocking calculator answers the bioload question with inch-per-gallon, surface-area and filtration-turnover rules for community, cichlid, marine and reef setups; the substrate calculator converts footprint and bed depth into pounds of gravel, sand or planted soil — and the bags to buy.

Reach for these when…

  • You are choosing fish for a new or existing tank
  • A community, cichlid, marine or reef stocking limit is unclear
  • You need pounds of gravel or sand for a target bed depth
  • A planted tank needs aqua soil coverage math
🐟

Fish Tank Stocking Calculator

How many fish fit in your tank? Calculate stocking density from bioload, inch-per-gallon and surface area rules for freshwater, cichlid and reef tanks.

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🪨

Aquarium Substrate Calculator

How much gravel, sand or planted tank soil do you need? Weight in lb and kg from tank footprint and bed depth, with reef sand bed guidance and bag conversions.

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05

Flow, Drain & Pressure

Once a tank holds liquid, physics takes over. The drain-time calculator handles orifice flow, gravity drain, pump fill/empty, two-tank transfer and pressurized outflow; the pressure calculator converts liquid depth into psi and computes the total force pushing on a tank wall. Both use the same constants — 0.433 psi per foot of freshwater, Torricelli at the outlet — so drain-time and wall-force answers stay consistent.

Reach for these when…

  • You need drain or fill time for a tank, pool or vessel
  • An outlet hole, siphon or pump sets the flow rate
  • You want psi at the bottom or on a glass wall
  • A level reading has to become pressure (or the reverse)
🚰

Tank Drain Time & Flow Rate Calculator

Calculate tank drain time, fill time and flow rate — Torricelli orifice flow, gravity drain, pump fill/empty times, two-tank transfer and pressurized outflow.

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🧯

Tank Pressure Calculator

Hydrostatic pressure at any tank depth in psi, bar and kPa — plus total force on aquarium glass walls, freshwater vs saltwater and liquid level to psi.

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06

Compressed Air

Air receivers follow different physics from liquid tanks — compressibility, not density, sets the math. This calculator sizes a receiver from compressor CFM and duty, computes usable drawdown between cut-in and cut-off pressures by Boyle's law, fill time to a target pressure, and bare geometry in gallons.

Reach for these when…

  • Matching receiver gallons to compressor CFM and duty
  • Computing usable air between cut-in and cut-off pressure
  • Predicting how long a tank takes to reach working pressure
  • Converting receiver geometry to gallons and cubic feet
🌬️

Air Receiver Tank Size Calculator

Size an air receiver from compressor CFM and demand — usable air between cut-in and cut-off pressure by Boyle's law, fill time and gallon conversions.

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07

Pipeline & Piping

Every pipe is a long, thin cylinder — and the formulas are the same πr²L geometry the tank engine uses, just applied to tubes instead of shells. The pipe volume calculator returns gallons per foot, total gallons for a run, fill time from a GPM figure, and standard PVC and steel pipe lookup so you can size a line or estimate a system without hand math.

Reach for these when…

  • A plumbing or irrigation run needs total volume and fill time
  • Designing a pipe coil or heat exchanger and need internal volume
  • Sizing a condensate line or hydronic loop by water capacity
  • Estimating how much inhibitor or treatment to dose into a pipeline
🟦

Pipe Volume Calculator

Calculate pipe volume in gallons, liters and cubic feet from diameter and length — with wall-thickness correction, PVC and steel pipe size lookup, total pipeline mode and fill-time math.

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08

Volume & Area Conversions

Three conversions sit between almost every tank job: gallons ↔ square feet for surface water and pond planning, liters ↔ gallons for cross-border spec sheets, and cubic feet ↔ gallons ↔ square feet for civil work. These calculators tie every pair together — with quick formulas, live bidirectional input and conversion tables you can keep open in a second tab.

Reach for these when…

  • A pond or pool design needs gallons from square feet and depth
  • Quoting or ordering from both imperial and metric suppliers
  • Converting between m³, liters, gallons and ft³ for engineering docs
  • Checking rainfall catchment or irrigation coverage per gallon
🌊

Gallons to Square Feet Converter

Convert gallons to square feet and back for ponds, pools, irrigation and rainwater — with depth assumption presets, cubic feet ↔ square feet ↔ gallons three-way conversion.

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🔄

Liter to Gallon Converter

Live bidirectional liter to gallon converter supporting both US and imperial gallons — with quick reference formula, 1–100 L conversion table and cubic meter ↔ liter ↔ gallon chain.

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09

Volume ↔ Weight

Volume answers how much fits; weight answers what it loads — and the density gap between water, diesel and gasoline is large enough that guessing at it breaks trucks and pads. The liquid-weight calculator converts any volume to pounds, kilograms and tons from a density preset (water, diesel, gasoline, milk, seawater, custom SG) and runs both directions so a weight target becomes a volume number you can fill to.

Reach for these when…

  • Turning gallons of diesel, water or gasoline into pounds or kilograms
  • Designing a tank pad or stand from filled weight
  • A recipe or process needs to know what a given volume of liquid weighs
  • Checking temperature effects on water density between summer and winter
⚖️

Liquid Weight Calculator

Convert gallons to pounds and liters to kilograms for water, diesel, gasoline, milk, seawater and any custom SG — bidirectional mode, temperature-corrected water density, tons output.

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⚙️

Tank Shell Weight Calculator

Calculate empty tank shell weight for steel, stainless steel and aluminum — vertical/horizontal cylinder and rectangular shells, wall thickness to weight, aquarium glass thickness.

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One Model, Proven

One Tank, Four Tools, Zero Disagreement

The test of a shared model is simple: run the same tank through every tool and the story has to stay consistent. Here is the classic 275-gallon home heating-oil tank through the four tools it meets most often — every figure traces back to the same 27 × 44 × 60 inch oval geometry.

STEP 1

Volume calculator

268 US gallons total

A classic 275-gal home heating-oil tank — 27" × 44" × 60" with an oval cross-section — works out to 268 gal of geometric capacity. The nameplate rounds up.

STEP 2

Dip chart generator

≈21% at quarter depth

An 11-inch dipstick reading in that tank is about 57 gallons — 21% of capacity, not the 25% a straight-line guess would give. The strapping table converts every future reading to gallons on sight.

STEP 3

Liquid weight converter

≈1,900 lb of heating oil

Heating oil runs SG 0.85 — about 7.1 lb per gallon. Two hundred gallons in the tank puts over 1,400 lb on the stand and the floor joists.

STEP 4

Tilt correction

Real volume at the real angle

Installers slope oil tanks toward the drain end. At 1.5° over 60 inches the ends differ by 1.6 inches of depth — the correction integrates the whole length.

A technician measuring a storage tank before running the calculatorSame tank, every tool, every timePhoto: Unsplash

Why This Matters on a Real Job

The classic failure is not one bad number — it is two good numbers that were never talking. A stand sized for water while the tank holds oil. A delivery ordered from a linear guess of the dipstick. A capacity quoted from a flat-end formula on a dished vessel. Each one is an honest mistake made across tool boundaries.

Sharing one model is the structural fix. The head geometry that sets your capacity also sets your dip chart; the density that weighs your inventory also loads your truck. When the definitions are shared, the mistakes get caught by arithmetic instead of by the crew.

Run your tank now
Quick Router

Which Tool Answers Your Question?

Find the question you are holding, follow the row, open the tool. Every calculator is one click from this table — and back to the volume engine when the next question starts.

If you need to know…
Open…
You get…
How many gallons does this tank hold?
💧Water Tank Capacity Calculator
Capacity in gal, L, m³, ft³
How much is in it right now?
⛽Diesel & Fuel Tank Calculator
Filled volume and % full with SG
What volume does my dipstick reading mean?
🛢️Heating Oil Tank Size Calculator
Oval cross-section dip chart
How much can I still add before it is full?
🛢️Horizontal Cylinder Tank Volume Calculator
Partial fill curve + ullage
Do the dished ends change the capacity?
🛢️Horizontal Cylinder Tank Volume Calculator
Flat vs hemisphere vs 2:1 elliptical
What size propane tank do I need?
🔥Propane Tank Size Calculator
BTU demand → tank size with 80% fill
What will the contents weigh when full?
⛽Diesel & Fuel Tank Calculator
lb, kg and tons at any SG
I need a tank that holds X gallons — what size should it be?
💧Water Tank Capacity Calculator
Round / rectangular sizing by volume
How many liters is my fish tank?
🐠Fish Tank Volume Calculator
Gallon ↔ liter after glass correction
How long does this tank take to drain — or fill?
🚰Tank Drain Time & Flow Rate Calculator
Gravity, pump, orifice & transfer times
How many fish can this tank hold?
🐟Fish Tank Stocking Calculator
Bioload, inch-per-gallon & surface limits
How much gravel or sand does the bottom need?
🪨Aquarium Substrate Calculator
Weight in lb/kg + bags to buy
What psi is at the bottom — or on the glass?
🧯Tank Pressure Calculator
psi, bar, kPa & wall force
What volume does the cone bottom add?
🔻Cone Bottom Tank Volume Calculator
Frustum + shell at any liquid level
What size air receiver does my compressor need?
🌬️Air Receiver Tank Size Calculator
CFM sizing, drawdown & fill time
How much water fits in that pipe or pipeline?
🟦Pipe Volume Calculator
Gallons per foot, total gallons, fill time
How many gallons does my pond or pool hold?
🌊Gallons to Square Feet Converter
Square feet × depth → gallons, 3-way converter
Convert between liters and gallons (US or imperial)?
🔄Liter to Gallon Converter
Live bidirectional, 1–100 L table, m³ chain
How heavy is 50 gallons of water or diesel?
⚖️Liquid Weight Calculator
Volume ↔ weight, 7 liquids, temperature correction
The Core Tool

Inside the Tank Volume Calculator

The volume calculator is where the whole toolset begins, and its inputs are the vocabulary every other tool assumes you know. Six settings do all the work — each one mapped to a decision you make on the job, none of them hidden behind an account or a paywall.

10 tank shapes

Horizontal and vertical cylinders, rectangle, ovals, capsules, ellipse, 2:1 elliptical and dish ends — the full field repertoire in one dropdown.

Dish-end head geometry

Flat, hemispherical, 2:1 elliptical and torispherical heads, each reported separately from the shell, with custom dish depth support.

Liquid weights built in

Water, diesel, gasoline, milk, crude oil and more — or a custom density in SG, kg/m³ or lb/gal — converted to pounds, kilograms and tons.

Imperial and metric together

Each dimension carries its own unit selector — in, ft, yd, mm, cm, m — and every result shows its twin so cross-border spec sheets never need a second conversion.

Tilt correction

Sloped installations are the norm, not the exception. Enter the angle and where you dipped, and the engine integrates the depth along the whole shell.

Live on every keystroke

No calculate button, no sign-up, no result caps. Change a dimension and watch the diagram, volume and weight move before your finger leaves the key.

From Dimensions to a Defensible Number

Under the hood the engine runs the closed-form volume of the shape you picked, the circular-segment integral for anything partially filled, the head formulas when the ends are not flat, and the density conversion when weight matters. Nothing is tabulated or approximated behind the curtain — every figure traces to a formula the site publishes.

The outputs are organized the way the work is read: capacity first, because it drives sizing and ordering; then the filled volume and ullage that drive deliveries; then the weight that drives stands, pads and trucks. The dip chart turns the same geometry into a field document.

Walk the full how-to
Gauge measurements being taken on an industrial tankTwo dimensions in, every number outPhoto: Unsplash
Trust, Then Verify

Four Hand Checks for Any Result

A calculator that hides its math is asking for blind trust; this one does not. Every figure the toolset produces can be reproduced with a tape measure, a phone calculator, and the four checks below — the same mental math operators have used for decades, refined to the decimal by the engine. Run them once on a tank you already know, and the tool has earned its place on the job.

1

Check the capacity against the πr²L rule

gal ≈ 0.0034 × D² × L

Full-cylinder capacity in US gallons from diameter and length in inches — a 27" × 60" tank works out to 148.7 gal. Run the calculator on the same tank: the totals should match to the decimal, because both come from the same geometry (π × 13.5² × 60 = 34,353 in³ ÷ 231).

2

Check the fill against the quarter-depth curve

25% depth ≈ 19.6% of volume

A horizontal cylinder filled to a quarter of its depth holds about a fifth of its capacity — the circle is narrow at the bottom. Any dip-chart row that disagrees wildly with this curve on a round tank has an input problem: the wrong diameter, the wrong depth basis, or the wrong tank.

3

Check the heads against πr³/3

2:1 elliptical head = πr³/3 each

One 2:1 elliptical head holds πr³/3 — on a 27" tank that is about 2,576 in³ per head, or 22.3 gallons for the pair. The head-vs-shell breakdown should show exactly that figure for the 2:1 option, with the hemispherical rows above it and the F&D rows below it in the same proportion.

4

Check the weight against 8.34 lb/gal

lb = gal × 8.34 × SG

Water weighs 8.34 lb per gallon; multiply by the liquid's specific gravity for anything else — diesel at SG 0.84 runs about 7.0 lb/gal. A 148.7-gallon tank of diesel should read roughly 1,040 lb full, and the weight converter will show it to the pound.

Tank reference charts and a laptop with the tank calculator open on a workbenchEvery tool has a guide behind itPhoto: Unsplash
Tools + Guides

Not Sure Which Number to Trust? Read the Guide.

Every calculator on this page has a matching set of guides that explain the ideas behind its inputs — what a dip chart actually tabulates, why curved heads change capacity, where the circular-segment integral comes from, and how to check a supplier's capacity figure against your own measurements.

The guides and the tools are written as a pair: the reading explains why a number moves, the tool shows how far it moves. If a result ever surprises you, the guide library is the fastest way to find out whether the surprise is the math or the measurement.

Browse the guide library

Questions About the Toolset

Are all of the calculators free to use?▼

Yes — every tool on this page is free, requires no account, and has no usage caps or paywalled fields. The site is a reference toolset, not a lead-generation funnel: nothing gates a result, and no result is emailed to anyone.

Do the calculators share inputs with each other?▼

They share the geometry, not a session. Each tool is a view of the same tank model — the dip chart generator reads the same dimensions and head settings as the main volume calculator — so a figure from one tool is always consistent with the others. There is no second copy of the math to drift out of date.

Where do the numbers come from?▼

Exact solid geometry. Total capacity follows the closed-form volume of each shape; partial fills use the circular-segment and spherical-cap integrals the industry handbooks publish; head volumes use the standard per-head formulas (πr³/3 for 2:1 elliptical, 0.0809·D³ for ASME F&D style dished ends). Each section of the site shows the formula it applies so you can verify any result by hand.

Which calculator should I start with?▼

The tank volume calculator. It is the hub: the capacity and filled-volume figures it produces feed dip charts, weight planning and head corrections. Start with the shape and inside dimensions you actually have, then follow the links from this page to the tool that answers the next question about that same tank.

Can I work in metric only?▼

Yes. Every dimension field has its own unit selector — millimeters, centimeters and meters included — and results appear in liters and cubic meters beside the US units. A metric-only run never needs a manual conversion, and an imperial nameplate can be entered inch by inch on the same page.

How can I verify a result before I rely on it?▼

Use the four hand checks on this page: the πr²L capacity rule, the quarter-depth fill curve, the πr³/3 head factor, and 8.34 lb/gal times specific gravity. Each one reproduces a calculator output from published geometry, so any number can be confirmed in about a minute — without trusting anyone's code, ours included.

Can I request a calculator that is not here yet?▼

Please do. Send the calculation you keep doing by hand — what inputs you start from, what result you need out — through the contact page. Requests that describe a real, repeated field problem go to the top of the queue, and the toolset grows the same way the guide library does: from questions that were worth writing down.

Run Your First Tank Now

Pick a shape, enter the inside dimensions, and set a fill depth — the engine returns capacity, filled volume, ullage and weight in one keystroke. Then generate the dip chart the gauge stick deserves. Free, private, and instant.

Open the Tank Volume Calculator Read the Guides First