Tank Dip Chart Generator
Build a custom tank dip chart — also called a strapping chart or calibration chart — from your own measurements. Enter a horizontal cylinder, vertical cylinder, or rectangular tank's dimensions and get a level-to-volume table from empty to full, in US or imperial gallons, litres, cubic feet, or cubic metres. Read the depth with a dipstick, then look up the volume.
≈ 49 rows
What this tool does
This generator turns a tank's dimensions into a printable level-to-volume chart. Instead of a single capacity figure, it lists the volume at every depth step you choose — every inch, half inch, centimetre, or a custom increment — so you can read how much liquid is in the tank at any dipstick reading. It works for the three most common storage shapes and uses the same exact volume math as the main tank volume calculator.
What is a tank dip chart?
A tank dip chart (or dipstick chart) is a reference table that converts a measured liquid depth into a volume. You drop a stick into the tank, read how many inches or centimetres are wet, and look that number up in the chart to find the gallons or litres held at that level. Because the relationship between depth and volume depends on the tank's shape and orientation, each tank needs its own chart — which is exactly what this tool produces for your dimensions.
Dip chart vs strapping chart vs calibration chart
These terms are largely interchangeable. A dip chart or dipstick chart emphasises the measuring method. A strapping chart takes its name from the practice of "strapping" a tank — physically measuring it band by band — to build the table; you will see this term most in fuel, oil, and bulk storage. A calibration chart or tank chart is the same level-to-volume table in industrial use. A formal strapping table for custody transfer is made by precise physical survey; the chart here is a geometric calculation from the dimensions you provide, which is ideal for planning, estimating, and everyday tank reading.
How to read a tank with a dipstick
Use a clean, straight stick or rod that is longer than the tank is deep so it cannot fall in. Lower it vertically through the gauge or fill opening until it just touches the bottom, withdraw it, and read how far up the stick is wet with liquid. That wetted depth is your level. Find it in the left column of your generated chart and read across to the filled volume. Take readings with the tank settled and on level ground; tilt, sludge, or water sitting under the product will shift the true figure.
Why horizontal tank charts are not linear
A horizontal cylinder does not fill evenly with depth. The liquid surface cuts a horizontal chord across the round cross-section, so the wetted area is a circular segment. Near the bottom and the top, an inch of depth spans only a narrow part of the circle and adds little volume; through the middle, the same inch spans the widest part and adds much more. That is why a horizontal tank's dip chart has unevenly spaced volumes and why a sight gauge on a horizontal tank is not evenly marked. Vertical cylinders and rectangular tanks fill on a constant footprint, so their charts rise in a straight line.
How the numbers are calculated
Every value comes from exact tank geometry, not a lookup table. For a vertical cylinder and a rectangle, filled volume is the constant cross-section area times the liquid depth. For a horizontal cylinder, the filled cross-section is a circular segment of area r² · arccos((r − h) / r) − (r − h) · √(2rh − h²), multiplied by the tank length. The tool computes the volume at each level, converts to your chosen unit, and reports filled volume, percent full, and the empty volume remaining. Full details are on the methodology page.
Which tank shape to choose
- Horizontal cylinder — a round tank lying on its side: most fuel, heating-oil, and many water and chemical tanks. Enter the diameter and length. See the dedicated horizontal cylindrical tank calculator.
- Vertical cylinder — an upright round tank. Enter the diameter and height (length). See the vertical cylindrical tank calculator.
- Rectangle / box — a square or rectangular tank. Enter length, width, and height. See the rectangular tank calculator.
For common heating-oil tanks (275, 330, 500, 550, 1000 gallon) in standard sizes, the pre-built heating oil tank chart may be quicker than entering dimensions.
Print, copy, and CSV
Once your chart is generated you have three ways to keep it. Copy table places a tab-separated copy on your clipboard that pastes cleanly into Excel, Google Sheets, or Numbers. Download CSV saves a spreadsheet file. Print opens your browser's print dialog — to make a PDF, choose "Save as PDF" as the print destination. A laminated printout kept by the tank is a handy field reference.
Accuracy and limitations
The chart is an exact calculation for an ideal tank of the size you enter, but real tanks differ. These figures do not account for:
- End shape: dished, domed, or hemispherical ends hold more than the flat-ended models used here.
- Wall thickness and fittings: the calculation uses the dimensions you enter as internal capacity; internal structures and thick walls reduce usable volume.
- Tilt and ground: a tank that is not level reads differently from a perfectly level one.
- Bottom volume: sludge, water, and product below the outlet may be present but unusable.
Disclaimer: This chart provides approximate calculated estimates for planning and reference. For billing, deliveries, or custody transfer, rely on a supplier's metered or surveyed measurement.
Frequently asked questions
What is a tank dip chart?
A tank dip chart is a table that converts the depth of liquid in a tank into a volume. You measure the level with a dipstick (or a gauge), find that reading in the chart, and read across to the corresponding volume. Because tank shapes vary, every tank size and orientation has its own chart. This generator builds one for your exact dimensions, with rows from empty to full at the increment you choose.
What is the difference between a dip chart, strapping chart, and calibration chart?
They usually describe the same thing: a level-to-volume reference table for a tank. “Dip chart” and “dipstick chart” come from measuring with a stick; “strapping chart” comes from the older practice of “strapping” (physically measuring) a tank to build its table; “calibration chart” and “tank chart” are the same idea in industrial settings. A formal, custody-transfer strapping table is created by precise physical measurement; the chart here is a geometric calculation from the dimensions you enter.
How do I make a dip chart for my tank?
Pick your tank shape (horizontal cylinder, vertical cylinder, or rectangle), choose the unit you measured in, and enter the dimensions. Choose how fine you want the rows — every 1 inch, every half inch, every 1 cm, or a custom step — and the output volume unit. Then select Generate chart. You can copy the table, download it as CSV, or print it (including Save as PDF).
Why is a horizontal tank dip chart not evenly spaced?
A horizontal cylinder fills as a circular segment, not as a simple fraction of its height. Near the bottom and top a given inch of depth covers a narrow slice of the circle, so it adds little volume; through the middle the same inch covers the widest part and adds much more. That is why the gallons-per-inch on a horizontal tank change with depth, and why the chart rows are unevenly spaced. Vertical cylinders and rectangles fill on a constant footprint, so their charts are linear.
How do I measure tank level with a dipstick?
Use a clean, straight stick or rod long enough that it cannot fall into the tank. Lower it vertically through the gauge opening until it touches the bottom, withdraw it, and read how far up the stick is wet. That wetted depth is the level you look up in the chart. Take the reading with the tank settled and on level ground; tilt, sludge, or water at the bottom will affect the result.
Can I make a dip chart in inches and centimetres?
Yes. You can enter dimensions in inches, feet, centimetres, or metres, and choose a chart increment of 1 inch, 0.5 inch, 1 cm, or a custom step in inches or centimetres. The level column is shown in the unit of your increment, and the volume columns can be US gallons, imperial gallons, litres, cubic feet, or cubic metres.
How accurate is a calculated tank dip chart?
It is an exact geometric calculation for an ideal tank of the dimensions you enter, using the same volume math as the rest of this site. Real tanks differ: wall thickness, dished or rounded ends, tilt, dents, internal fittings, sludge, and unusable bottom volume all shift the true figures. Treat the chart as a planning estimate, and rely on a supplier's metered measurement for billing or custody transfer.
Can I download or print the chart?
Yes. After generating, use Copy table to paste it into a spreadsheet, Download CSV to save a file, or Print for a paper copy. To create a PDF, choose Print and select “Save as PDF” as the destination in your browser's print dialog — there is no separate download needed.