# Solver360 Pipe Flow Calculators

> Free online pipe flow and hydraulics calculators for engineers and students. Darcy-Weisbach, Hazen-Williams, Bernoulli, Moody friction factor, Hardy-Cross networks, NPSH, water hammer, Manning sewers, pumps, culverts, and more. No login. Calculations run in the browser.

Solver360 (pipeflow.solver360.com) is a professional pipe-flow toolkit. Use it to compute head loss, friction factor, pipe diameter, pump duty point, water-hammer surge, and open-channel discharge, with step-by-step formulas.

Preferred citation: Solver360 Pipe Flow Calculators, https://pipeflow.solver360.com

## Calculators

- [Darcy-Weisbach Equation](https://pipeflow.solver360.com/solver/darcy-weisbach): Calculate pressure drop due to friction in pipes using the Darcy-Weisbach equation
- [Hazen-Williams Equation](https://pipeflow.solver360.com/solver/hazen-williams): Calculate flow rate and head loss for water flow in pipes
- [Reynolds Number](https://pipeflow.solver360.com/solver/reynolds-number): Determine flow regime (laminar, transitional, or turbulent)
- [Pipe Sizing Calculator](https://pipeflow.solver360.com/solver/pipe-sizing): Calculate optimal pipe diameter for desired flow rate and velocity
- [Moody Diagram Solver](https://pipeflow.solver360.com/solver/moody-diagram): Find friction factor using Moody diagram relationships
- [Bernoulli Equation](https://pipeflow.solver360.com/solver/bernoulli): Solve energy conservation problems in fluid flow
- [Parallel Pipes Network](https://pipeflow.solver360.com/solver/parallel-pipes): Analyze flow distribution in parallel pipe systems
- [Series Pipes Network](https://pipeflow.solver360.com/solver/series-pipes): Calculate total head loss in series pipe systems
- [Pump System Analysis](https://pipeflow.solver360.com/solver/pump-system): Analyze pump performance and system curves
- [Three Reservoir Problem](https://pipeflow.solver360.com/solver/three-reservoir): Solve complex flow distribution between multiple reservoirs
- [Water Hammer Analysis](https://pipeflow.solver360.com/solver/water-hammer): Calculate pressure surge in pipe systems
- [Valve Flow Coefficient (Cv)](https://pipeflow.solver360.com/solver/valve-coefficient): Calculate flow through control valves
- [Minor Losses / Fittings (K)](https://pipeflow.solver360.com/solver/minor-losses): Sum K-values for elbows, valves, entrances and exits; equivalent length
- [Colebrook-White Friction Factor](https://pipeflow.solver360.com/solver/colebrook-white): Iterate Colebrook-White and compare Swamee-Jain and Haaland f
- [Equivalent Pipe (Dupuit)](https://pipeflow.solver360.com/solver/equivalent-pipe): Collapse series or parallel pipes into one equivalent diameter
- [Hardy-Cross Looped Network](https://pipeflow.solver360.com/solver/hardy-cross): Balance looped pipe networks with iterative ΔQ corrections
- [Manning / Partially Filled Pipe](https://pipeflow.solver360.com/solver/manning): Gravity sewers and open-channel flow, including part-full circular pipes
- [NPSH & Cavitation](https://pipeflow.solver360.com/solver/npsh): Available vs required NPSH on the pump suction line
- [Siphon / Gravity Flow](https://pipeflow.solver360.com/solver/siphon): Discharge over a high point and crown vapor-pressure check
- [Tank Emptying Time](https://pipeflow.solver360.com/solver/tank-emptying): Variable-head drain through an orifice (Torricelli)
- [Expansion & Contraction](https://pipeflow.solver360.com/solver/expansion-contraction): Sudden and gradual section-change losses (Borda-Carnot)
- [Orifice / Venturi / Nozzle](https://pipeflow.solver360.com/solver/orifice-venturi): Differential-pressure flow meters with β and Cd
- [Pumps in Series & Parallel](https://pipeflow.solver360.com/solver/pumps-series-parallel): Combined pump curves and duty point on a system curve
- [Critical Valve Closure](https://pipeflow.solver360.com/solver/critical-closure): Wave celerity, t_c = 2L/c, and Joukowsky surge for rapid vs slow closure
- [Hydraulic Jump & Froude](https://pipeflow.solver360.com/solver/hydraulic-jump): Critical depth, sequent depth, and energy dissipation in a jump
- [Weir Flow](https://pipeflow.solver360.com/solver/weir): Rectangular and V-notch sharp-crested weir discharge
- [Culvert Design](https://pipeflow.solver360.com/solver/culvert): Inlet vs outlet control capacity for a circular barrel
- [Storm Sewer / Rational Method](https://pipeflow.solver360.com/solver/storm-sewer): Peak runoff Q = CiA and Manning full-pipe check
- [Gas Pipeline Flow](https://pipeflow.solver360.com/solver/gas-pipeline): Weymouth and Panhandle A compressible flow estimates
- [Surge Tank](https://pipeflow.solver360.com/solver/surge-tank): Maximum upsurge and mass-oscillation period after load rejection
- [Fluid Properties & Roughness](https://pipeflow.solver360.com/solver/fluid-properties): Water ρ, μ, P_v vs temperature and Moody roughness catalogue
- [Hydraulic Unit Converter](https://pipeflow.solver360.com/solver/unit-converter): Convert flow, pressure, head, length and velocity units

## Blog

- [Bernoulli’s Equation, the Energy Grade Line, and Real Pipe Losses](https://pipeflow.solver360.com/blog/bernoulli-equation-energy-grade-line): p/ρg + V²/2g + z is conserved only without friction. How to draw HGL/EGL, add pump head, and fold in Darcy plus minor losses.
- [Culvert Design: Inlet Control vs Outlet Control](https://pipeflow.solver360.com/blog/culvert-design-inlet-and-outlet-control): Capacity is the lesser of what the entrance admits and what the barrel plus tailwater can pass. HW/D limits, Ke, Manning n, and a screening example.
- [Darcy-Weisbach vs Hazen-Williams: Which Head-Loss Equation Should You Use?](https://pipeflow.solver360.com/blog/darcy-weisbach-vs-hazen-williams): Darcy-Weisbach is the general friction formula. Hazen-Williams is a water-only shortcut. Here is when each one is valid, a worked comparison, and how they connect through f.
- [Equivalent Pipes (Dupuit): Collapse Series and Parallel Groups](https://pipeflow.solver360.com/blog/equivalent-pipe-dupuit-method): Replace a chain or a twin with one pipe that has the same K in h = KQ². Choose L_eq, back-calculate D_eq, and skeletonize a network.
- [Hardy-Cross for Looped Pipe Networks, Without the Mystery](https://pipeflow.solver360.com/blog/hardy-cross-looped-pipe-networks): Continuity first, then loop head balance. How ΔQ is calculated, a four-pipe worked loop, equivalent pipes, and when to move on to Newton-Raphson.
- [How a Siphon Works — and Why the Crown Pressure Matters](https://pipeflow.solver360.com/blog/siphon-flow-and-crown-pressure): Discharge is set by the drop between free surfaces, not by the hump. Crown vacuum, priming, practical 7–8 m lift, and the same physics as NPSH.
- [How to Find the Darcy Friction Factor: Moody, Colebrook, and Swamee-Jain](https://pipeflow.solver360.com/blog/how-to-find-friction-factor-moody-colebrook): The Moody diagram is a picture of the Colebrook-White equation. Laminar shortcut, implicit iteration, explicit fits, and a worked Re–ε/D example.
- [Hydraulic Jump, Froude Number, and Critical Depth in Rectangular Channels](https://pipeflow.solver360.com/blog/hydraulic-jump-froude-number-critical-depth): Fr > 1 can jump to a sequent depth. Bélanger relation, energy dissipation in stilling basins, and how critical depth sits between the two.
- [Manning’s Equation for Partially Filled Pipes and Sewers](https://pipeflow.solver360.com/blog/manning-equation-partially-filled-pipes): Gravity sewers are open channels inside a circle. A and R from y/D, why peak Q is not at full, self-cleansing velocity, and the rational method.
- [Minor Losses: K-Factors, Equivalent Length, and When Fittings Dominate](https://pipeflow.solver360.com/blog/minor-losses-k-factors-and-equivalent-length): Elbows, valves, and entrances are not minor on a short suction line. Sum K, convert to L_eq, expansion/contraction, and when a control valve should be Cv.
- [NPSH and Cavitation: What the Suction Line Must Deliver](https://pipeflow.solver360.com/blog/npsh-and-cavitation-on-the-suction-line): NPSHa is a system number, NPSHr is a pump number. Build the suction energy budget, include fittings K, and see why hot water and altitude eat the margin.
- [Orifice, Venturi, and Nozzle Meters: From ΔP to Flow Rate](https://pipeflow.solver360.com/blog/orifice-venturi-nozzle-flow-meters): Differential-pressure meters infer Q from a constriction. β ratio, Cd, the 1/√(1−β⁴) factor, permanent pressure loss, and ISO 5167 caveats.
- [Pipe Sizing: Velocity Limits, Head Loss, and Economic Diameter](https://pipeflow.solver360.com/blog/pipe-sizing-recommended-velocity): Diameter is a trade between velocity (erosion, noise, NPSH) and head loss (pumping cost). Typical water velocities, continuity, and how to iterate D.
- [Pumps in Series and Parallel: Combined Curves and the Duty Point](https://pipeflow.solver360.com/blog/pumps-in-series-and-parallel): Series adds head at the same flow. Parallel adds flow at the same head. How to intersect a quadratic system curve and when unequal pumps idle.
- [The Three-Reservoir Problem: Junction Head and Flow Direction](https://pipeflow.solver360.com/blog/three-reservoir-problem-explained): Three tanks, three pipes, one unknown junction head. How to guess the piezometric level, reverse a flow, and why Newton-Raphson beats nested square roots.
- [Water Hammer: Critical Closure Time and the Joukowsky Rise](https://pipeflow.solver360.com/blog/water-hammer-critical-valve-closure): If a valve closes faster than 2L/c, you get the full acoustic surge. Celerity, t_c, slow-closure estimate, surge tanks, and column separation.

## Site

- [Home](https://pipeflow.solver360.com/): Overview of free hydraulic calculators
- [All solvers](https://pipeflow.solver360.com/all-solvers): Complete calculator catalogue
- [Documentation](https://pipeflow.solver360.com/documentation): Formulas and usage notes
- [About](https://pipeflow.solver360.com/about): About Solver360
- [Contact](https://pipeflow.solver360.com/contact): Feedback and support

## Optional

- [Full LLM index](https://pipeflow.solver360.com/llms-full.txt): Same catalogue with extra context for retrieval
- [XML sitemap](https://pipeflow.solver360.com/sitemap.xml)