Pump Output & Circulation
Mud-pump output and circulation maths — triplex and duplex output per stroke and flow rate, annular velocity, and strokes and time to circulate a volume. Field and metric units, fully offline.
Open Pump Output & Circulation →What is the pump output & circulation calculator?
A mud-pump calculator that runs entirely in your browser. It works out the output per stroke of a triplex or duplex pump from the liner diameter, stroke length and volumetric efficiency, then multiplies by pump speed to give the flow rate. It also finds the annular velocity — how fast mud travels up the annulus for a given flow rate, hole size and pipe size — and tells you how many strokes and how long it takes to circulate a chosen volume. Field units (in, bbl, gpm, ft/min) and metric units (mm, m³, L/min, m/min) are both supported, and every result updates as you type. Nothing is uploaded — the maths uses the standard Lapeyrouse/IADC constants and stays on your device.
How to use Pump Output & Circulation
- Choose your units — Use the Field / Metric switch at the top. Field is inches, barrels and gpm; metric is millimetres, cubic metres and litres per minute.
- Pick a calculation — Select a tab — Output, Annular velocity or Circulation — for the value you need.
- Set the pump type — On the Output tab, choose Triplex or Duplex. Duplex asks for the rod diameter as well, because the rod area is subtracted on the back stroke.
- Enter the known values — Type the liner and stroke sizes, efficiency and SPM (or flow rate, hole and pipe sizes, or a volume). The output per stroke, flow rate, velocity or strokes and time appear immediately.
Frequently asked questions
What is the difference between triplex and duplex output?
A triplex is single-acting with three pistons, so output depends on liner diameter and stroke length alone. A duplex is double-acting, so the piston rod area is subtracted on the return stroke — that is why the duplex calculation also needs the rod diameter.
What volumetric efficiency should I use?
Use the pump's actual efficiency if you know it. Triplex pumps typically run at 95–100%, duplex pumps around 85–95%. Leaving it at 100% gives the theoretical maximum output.
Why does annular velocity matter?
The mud must move fast enough in the annulus to lift cuttings to surface. Velocity is lowest in the widest annular section, so check that point against your minimum for good hole cleaning.
Does it work offline?
Yes. There are no dependencies and no network calls, so it runs on a rig laptop with no signal, and your last inputs are saved on your device.
Tips
- Output per stroke feeds straight into the Circulation tab — read it off the Output tab, then enter it there to get strokes and pump time.
- For hole cleaning, use the largest annular clearance (smallest Dh minus Dp) to find the slowest velocity in the well.
- Time to circulate assumes a steady pump speed; if the SPM changes, work each interval separately and add the strokes.