Drill Pipe Volume Calculator
Same volume in every unit
Fluid weight
Estimated fill / drain time
Your recent calculations (saved on this device)
| When | ID | Length | Result |
|---|
Enter the internal diameter of your drill pipe or tubing. Result defaults to barrels.
How to use this calculator
- Choose the unit system — US, Imperial or metric — at the top of the calculator.
- Pick the pipe type and schedule, then the nominal size, and the real inside diameter loads for you. Or choose Custom and type any bore.
- Enter the pipe length. Open Advanced to set fill level, number of identical runs, a fittings allowance, the fluid, or a flow rate.
- Press Calculate to see the volume in every unit, plus fluid weight, cross-section area and fill or drain time.
- Copy, share or print the result. Recent calculations are saved on your own device so you can reopen them later.
Tip: not sure where to start? Use the Fill example data button to load a complete worked example — a 2-inch Schedule 40 line, 50 ft long, at 10 gal/min — then adjust the numbers to match your job.
Real-world uses, with numbers
Charging a radiant-heat loop
How much water sits in a 300 ft run of ½" PEX.
≈ 2.9 US galSizing a well pressure tank
Line-fill volume in 100 ft of 1" Schedule 40.
≈ 4.5 US galFlushing a main
Water to displace in 100 ft of 4" Schedule 40.
≈ 66 gal · 250 LWater weight on hangers
Load from a full 100 ft run of 2" pipe.
≈ 145 lb · 66 kgMetric heating fill
Charge volume for 50 m of 28 mm bore.
≈ 30.8 LFuel or oil line contents
Diesel held in 20 m of 50 mm bore.
≈ 39 L · 33 kgMore questions, answered
How do I convert between gallons, litres and cubic metres?
1 US gallon = 3.785 litres; 1 Imperial gallon = 4.546 litres; 1 m³ = 1,000 litres = 264.2 US gallons. The calculator shows all of them from a single entry, so you never convert by hand.
Does the pipe material change the volume?
Only through the bore. Two pipes with the same inside diameter hold the same volume whether they are steel, PVC, copper or PEX. Material and schedule matter because they set the real inside diameter for a given nominal size.
How much does the water inside a pipe weigh?
About 8.34 lb per US gallon, or 1 kg per litre. A full 100 ft run of 2" Schedule 40 holds roughly 17.4 gallons, about 145 lb. Set the fluid in Advanced for hot water, glycol, diesel or seawater.
What if I only know the outside diameter?
Switch the diameter to OD mode and enter the wall thickness; the tool subtracts two wall thicknesses to reach the bore. For a listed standard, just pick the size and the published inside diameter loads automatically.
Can I use it for a part-full or sloped drain?
Yes for a straight, round pipe: open Advanced and set the fill level below 100%, and the volume scales with it. Truly partial gravity flow in a sloped line follows a curved free surface, so treat the part-full figure as an approximation.
Notes and derived figures
- Volume scales with the square of the bore: doubling the inside diameter roughly quadruples the capacity, while doubling the length only doubles it.
- Per-foot and per-metre capacity are constant for a given bore, so any length is a single multiplication — handy for quick field estimates.
- Nominal size is a label. A "2-inch" Schedule 40 pipe has a 2.067-inch bore; using "2" overstates the volume by more than a third.
- Fill and drain time is volume divided by flow rate. Enter a flow rate in Advanced to turn any result into a charge, flush or drain time.
Capacity, displacement and annulus
Three volumes come up on the rig. Capacity is what the inside of the string holds — that is what this tool computes from the internal diameter. Displacement is the steel cross-section the string pushes aside when it is run into a full hole. Annular volume is the space between the string and the hole or casing, which you find by computing the hole/casing capacity and subtracting the pipe's outside cross-section. Start from the internal capacity here and combine it with the other geometry in your circulation sheet.
Barrels per foot from the bore
Because oilfield work totals long strings, the useful number is barrels per foot. The relationship is the standard capacity factor:
bbl / ft = IDin² ÷ 1029.4
This is the internal-capacity form; use ID in inches.
For example, drill pipe with a 3.826 in bore holds about 0.01422 bbl/ft, so 10,000 ft of string contains roughly 142 barrels. The calculator applies the exact geometry and shows gallons and litres alongside for a cross-check.
Where drill-pipe volume is used
- Line fill and displacement — barrels to fill or displace the string.
- Slug and pill volumes — sizing a slug to pull dry pipe.
- Circulation and bottoms-up — string capacity feeds strokes-to-surface.
- Kill-sheet inputs — capacity factors for well-control calculations.
Accuracy and safety notes
Use the internal diameter for the specific pipe grade, weight and tool joints you are running — a heavier wall means a smaller bore. This tool gives geometric capacity only; it does not replace a well-control kill sheet or a rig-specific circulation calculation, and it does not account for tool-joint upsets, cuttings loading or compressible fluids. Treat it as a fast capacity estimate and confirm critical figures against your official procedures.
Reading and trusting your result
Here is how to read the number this drill pipe volume calculator gives you, and where it stops being exact.
What the figure represents
The headline value is the internal capacity of a round, uniform pipe running full — the fluid the bore can hold along the length you entered. Every other unit on the panel is the same physical quantity re-expressed, so you can quote whichever your paperwork needs without recalculating.
The full-pipe assumption
By default the figure assumes the pipe is completely full and perfectly cylindrical. For gravity drains and vented lines that run part full, set a fill level below 100% and the result scales with it. Bends, valves and fittings add a little capacity the straight-length model does not see — use the fittings allowance to approximate them.
Capacity reference tables & a worked example
Concrete numbers for this page, calculated the same way the tool above does — use them as a quick check or a lookup.
Internal capacity of 4-1/2" drill pipe
Downhole, tubular contents are counted in barrels, and the capacity comes straight from the internal diameter. A 4-1/2" drill pipe with a 3.826 in bore fills at 0.01422 bbl/ft — here is the pipe capacity down a string.
| Length (ft) | Capacity (bbl) | bbl/ft |
|---|---|---|
| 500 ft | 7.11 | 0.01422 |
| 1,000 ft | 14.22 | 0.01422 |
| 2,500 ft | 35.55 | 0.01422 |
| 5,000 ft | 71.10 | 0.01422 |
| 10,000 ft | 142.2 | 0.01422 |
| 15,000 ft | 213.3 | 0.01422 |
Capacity by drill-pipe size
Internal capacity per foot and per 1,000 ft across common API drill-pipe bores. These are pipe (internal) figures — annular volume between pipe and hole is a separate calculation.
| Size | ID (in) | bbl/ft | bbl per 1,000 ft |
|---|---|---|---|
| 2-7/8" | 2.441 | 0.00579 | 5.79 |
| 3-1/2" | 2.992 | 0.00870 | 8.70 |
| 4" | 3.340 | 0.01084 | 10.84 |
| 4-1/2" | 3.826 | 0.01422 | 14.22 |
| 5" | 4.276 | 0.01776 | 17.76 |
| 5-1/2" | 4.778 | 0.02218 | 22.18 |
Sizing a pump displacement
- Consider a 5" drill pipe, internal diameter 4.276 in.
- Capacity per foot = 0.01776 bbl, so a 9,000 ft string holds 0.01776 × 9,000 = 159.8 bbl.
- That is the volume to displace a plug from surface to bit through the pipe.
- Add the annulus separately when you need total hole volume — this table is pipe capacity only.
Frequently asked questions
How do I calculate drill pipe capacity?
Use bbl/ft = ID² ÷ 1029.4 with the internal diameter in inches, then multiply by length. Enter the bore above and the tool returns barrels, gallons and litres.
What is the difference between capacity and displacement?
Capacity is the fluid inside the string; displacement is the steel cross-section the string pushes aside when run into a full hole. This tool gives capacity.
How do I get annular volume?
Compute the hole or casing capacity, then subtract the pipe's outside cross-section. Use this tool for the internal figures and combine them in your circulation sheet.
Can I rely on this for well control?
No. It is a geometric capacity estimate. Well-control and kill-sheet figures must come from your rig's official procedures and verified capacity factors.
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What people say
Pipe capacity in bbl/ft without cracking the handbook. Displacement calc took thirty seconds.
Bore-based, not nominal — so the string volume actually agrees with the mud pumps.
Great for internal capacity; a built-in annulus mode would make it a one-stop tool.