Drill String - Hook Load

Drillstring hook-load calculation - weight of drill pipe + collars × buoyancy factor.

Drill stringHook loadDrilling

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

HL = W_{string} \cdot (1 - \rho_m/\rho_{steel})

Symbol	Meaning	Unit
$W$	String weight in air	kN
$ρ_m$	Mud density	kg/m³

Source: API Spec 7-1 / IADC

Drillstring hook-load calculation - weight of drill pipe + collars \u00d7 buoyancy factor.