Analyze flow using pressure, geometry, and losses. See volumetric flow, mass flow, and regime checks. Export neat reports and compare sample scenarios with confidence.
| Scenario | Model | Diameter (m) | Pressure drop (kPa) | Density (kg/m³) | Viscosity (Pa·s) | Flow (L/s) | Regime |
|---|---|---|---|---|---|---|---|
| Water in steel pipe | Pipe | 0.050 | 80.00 | 998.00 | 0.0010 | 9.5831 | Turbulent |
| Water through sharp orifice | Orifice | 0.030 | 60.00 | 998.00 | 0.0010 | 4.8056 | Turbulent |
| Light oil in long pipe | Pipe | 0.090 | 150.00 | 870.00 | 0.0120 | 39.0958 | Turbulent |
Area: A = πD² / 4
Effective pressure: ΔPeff = ΔP + ρgz
Orifice velocity: v = Cd √(2ΔPeff / ρ)
Pipe loss relation: ΔPeff = (ρv² / 2) [fL / D + K]
Laminar friction factor: f = 64 / Re
Turbulent friction factor: Swamee–Jain form estimates f from roughness and Reynolds number.
Volumetric flow: Q = Av
Mass flow: ṁ = ρQ
Reynolds number: Re = ρvD / μ
Fill time: t = V / Qsafe
Maximum flow describes the largest fluid rate that a system can sustain under a stated pressure difference, geometry, and loss profile. In physics, this topic connects pressure energy, kinetic energy, viscosity, wall friction, turbulence, and conservation laws. A useful calculator should not only produce one number. It should also show why that number changes when pipe diameter, roughness, fluid density, or available head changes. That is why this page reports velocity, mass flow, Reynolds number, head loss, and safe flow together.
Diameter is one of the strongest drivers because area grows with the square of diameter. Pressure difference also matters, but losses can consume the available energy before the fluid reaches the ideal velocity. For short openings, the orifice model is often appropriate. For longer piping, the Darcy–Weisbach relation is more realistic because it includes friction and local losses. Viscosity influences Reynolds number, and Reynolds number changes the friction factor. That feedback is why advanced flow estimates should use an iterative pipe calculation rather than a single shortcut.
Volumetric flow tells you how much space the fluid occupies each second. Mass flow shows how much material moves each second. Reynolds number helps identify laminar, transitional, or turbulent behavior. The safe flow value is simply the computed maximum divided by the selected safety factor, which can be helpful for design margins. The fill time estimate converts the calculated rate into a practical planning number. Use the graph to see how flow responds as pressure drop rises. When the curve bends gently, losses are dominating more of the available energy. For very precise design, always confirm assumptions, fluid properties, fittings, compressibility effects, and actual equipment limits with validated engineering data.
It is the highest predicted steady fluid rate for the entered pressure difference, geometry, and losses under the selected model assumptions.
Use pipe mode when fluid travels through a length of pipe where wall friction and fitting losses materially reduce the final flow rate.
Use orifice mode for short openings, nozzles, jets, and discharge holes where the main restriction is the outlet itself.
Reynolds number indicates whether flow is laminar, transitional, or turbulent. That regime strongly affects friction and therefore the predicted maximum flow.
The calculator divides the raw maximum flow by the safety factor. This gives a more conservative operating value for planning.
No. The formulas here assume incompressible single phase flow. Gas choking, expansion, and compressibility need different equations.
Rougher internal walls create more drag in turbulent flow. Higher drag raises head loss and lowers the achievable flow rate.
Use it for screening, comparison, and education. Final design should also check standards, measured properties, fittings, pumps, and manufacturer data.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.