Calculator

Drill Pipe Tally

Turn drill pipe OD, ID, joint length, and joint count into hole capacity, steel displacement, and a running joint-by-joint depth tally — the same math behind a physical tally book.

🔩 Pipe Specs
📏 String Make-Up
Capacity—
Displacement—
Total String Length—
Total Capacity Volume—
Total Displacement Volume—
Approx. Stands in String—
Reference only. A real tally is measured and logged joint by joint as pipe goes in the hole — use this to plan and sanity-check, not to replace the physical tally.

Running Tally

Cumulative depth, capacity, and displacement at each joint, assuming every joint equals the average length above.

Joint #Cumulative Depth (ft)Cum. Capacity (bbl)Cum. Displacement (bbl)

The Formulas Used

Capacity and Displacement
Capacity (bbl/ft) = ID² ÷ 1029.4
Displacement (bbl/ft) = (OD² − ID²) ÷ 1029.4
Same shape as the annular capacity formula on the lag & volume calculator — capacity uses the inside diameter, displacement uses the steel cross-section (OD minus ID).
Cumulative Depth at Joint N
Depth = N × Average Joint Length
Cumulative Volumes
Cumulative Capacity = Capacity/ft × Depth
Cumulative Displacement = Displacement/ft × Depth

This calculator handles one uniform section of pipe — a single OD/ID/weight run the length of the string. A real drill string usually pairs drill pipe with a shorter, heavier BHA or drill collars near the bit, which have their own OD and ID and need their own pass through the same formulas. The lag & volume calculator already handles a two-section string (drill pipe plus BHA) if that split matters for what you're working out.

Capacity and displacement here both come from a full circular cross-section. A horizontal tank on its side works from a related but different shape — a circular segment that changes with fill height rather than a constant bore — see the horizontal tank capacity calculator for that geometry.

For the constants written out with worked numbers, see the drilling formulas cheat sheet.

Frequently Asked Questions

What is a drill pipe tally and why does the crew keep one?

A tally is the running record of every joint made up into the string — its length, and the cumulative depth after it — built as pipe goes in the hole. It is the source of truth for how deep the bit actually is, since a driller's depth counter can drift but the tally is a physical measurement of what went in the hole, joint by joint.

Why do capacity and displacement matter beyond just knowing the string length?

Both feed the volumes that get watched while tripping. Displacement is how much mud the hole should lose as steel comes out (or take as steel goes in) — comparing that against what the trip tank actually shows is how a kick or a losses event gets caught while tripping, well before it would show up any other way. Capacity is what fills the string on the way back in, which sets strokes and time to bottoms-up once drilling resumes.

Why does average joint length vary from joint to joint?

Range 2 drill pipe (the most common range) runs roughly 30 to 32 feet per joint, but no two joints are cut to the exact same length — that is why a real tally is measured and logged joint by joint rather than assumed. The average joint length here is a planning figure; an actual tally always uses the measured length of each joint that went in the hole.

How is a stand different from a joint, and why does the average stand length matter?

A joint is a single length of pipe; a stand is two or three joints made up together and racked as one unit — a range 2 thribble (three joints) commonly runs around 90 to 94 feet. Stands, not joints, are what the crew actually racks and counts while tripping, so the stand count is the quicker cross-check against the joint-by-joint tally underneath it.