🛢️ Hole Volume Calculator
Enter a diameter and depth to get the volume in barrels — open-hole capacity, pipe capacity, or interval volume for mud, displacement, and cement planning.
🧮 Work Out the Barrels
What is a Hole Volume Calculator?
It converts a diameter and a length into a fluid volume in barrels. Square the diameter in inches, divide by the 1029.4 capacity factor, and multiply by the length in feet — the result is the capacity of that hole, pipe, or casing interval.
Use it to size mud systems, work out bottoms-up and lag, and plan cement, spacer, and displacement volumes. It assumes a nominal gauge diameter, so reconcile against measured returns where washout matters.
❓ Frequently Asked Questions
How is hole volume calculated?
Hole volume in barrels equals the diameter in inches squared, divided by 1029.4, times the length in feet: volume (bbl) = (D² / 1029.4) × length. The 1029.4 constant is the capacity factor that converts an inch diameter and a foot length straight into barrels, so an 8.5-inch hole to 10,000 ft holds about 701.9 bbl.
Where does the 1029.4 constant come from?
It's the reciprocal of the barrels-per-foot capacity for a one-inch diameter. A cylinder's cross-sectional area in square inches, converted to barrels per foot, gives a capacity of D²/1029.4 barrels per foot. Dividing the diameter squared by 1029.4 bakes that unit conversion into one number.
Can I use this for pipe or casing capacity?
Yes — enter the inside diameter of the pipe or casing instead of the hole diameter to get its internal capacity in barrels. The same formula gives annular or open-hole volume when you use the appropriate diameter; for an annulus, subtract the pipe-displacement volume separately.
Why does hole volume matter?
You need it to know your total circulating volume, to calculate bottoms-up and lag time, to plan mud mixing, and to size cement, spacer, and displacement volumes. Real volume varies with washout and hole enlargement, so this nominal figure is a planning baseline to reconcile against measured returns.