Dwellings
For residential work where the design intent is per-unit.
Water Pipe Sizing
Quick Water Calculator
Size a water pipe run in seconds, with Australian standards-aligned outputs you can defend in review.
The Quick Water Calculator is the everyday workhorse for single-run cold water pipe sizing. Open it, enter what you have, and get a defensible answer with the full pressure breakdown attached. Designed for Australian hydraulic design workflows, it references AS/NZS 3500 and uses Barrie's Book methodology to convert loading units into design flow, helping your team produce results that are easier to review, explain, and defend.
Inputs
Enter demand the way you actually have it
Clarus accepts three input paths, and you can mix them in a single calculation.
Loading units
When your riser schedule is already worked out.
Full flow
Already computed your L/s elsewhere, or have plant equipment that needs an undiversified full flow? Drop it in and Clarus sizes the pipe.
Pick your material from the supported catalogue, AS 1432 Copper Type B, 316L stainless, or PE100 blue stripe PN16. Enter source pressure, required residual at the index point, static height, index length, and desired velocity. Clarus does the rest.
Pump sizing, built in
When the system needs a pump, a pump duty is automatically generated to serve the full flow rate with enough residual pressure. Boost-from-main and pump-from-tank arrangements are both supported.
Check pressure at any point
Need residual at an intermediate fixture, not just the index point? The pressure-at-point query takes a distance and height and returns available pressure at that location, without rerunning the whole calculation.
Results
What you get back
Every Quick Calculation returns a complete, auditable result.
Recommended pipe size
Internal diameter, velocity, friction loss, and pressure margin against your required residual.
A capacity table for every size
Max safe flow, velocity, approximate loading units and dwellings supported, and what's limiting each one. The recommended size is flagged; neighbouring rows show the cost of going up or down.
A full pressure breakdown
Source pressure, pump contribution, static head loss, pipe friction, pump-room loss, safety margin, and final residual. Every term shown separately so a reviewer can audit it.
Pump results when needed
Required flow, required pressure and head, and pump-room loss with suction and delivery breakdown.
Standards & methodology on every result
Reviewers see exactly which standards, tables and design rationale the calculation used.
Why engineers use it
Why hydraulic engineers use it
Built for Australian design workflows
The AS/NZS 3500 probability flow curve, the verified fixture table, and material-specific friction tables are baked in, version-tracked, and stamped on every result. You don't have to remember which table you used; the PDF shows it.
Compliance, compliance, and compliance
Final PDF exports provide professional, accurate calculation methodology and sizing rationale, citing Australian standards clauses alongside other commonly used, trusted and recognised sizing resources.
Multiple demand methods in one tool
A single dwelling, a 7,000-LU mixed-use building, or a flow from mechanical plant can all be sized together in a single calculation. No switching tools mid-project.
The recommended size and its neighbours
Most calculators give you one answer. Clarus gives you the answer and the sizes around it, with the constraint limiting each. The "what if we drop one size?" conversation is already answered on screen.
Snapshot & project
Save calculations as snapshots tied to a moment in time and attach them to a project. You keep an auditable trail of what was sized, when, and against which standards, safeguarding you against compliance disputes.
When it grows
Built for the work you do every day
The Quick Calculator is for single-run sizing, fast. When a design grows past a single run, switch to Schematic Studio, a professional drafting environment that sizes every branch automatically as you sketch. Produce issue-ready schematics and advanced system calculations in minutes, with the same standards-aligned outputs behind every run.
Start your first water pipe sizing calculation
Spin up a free trial and size your first run in seconds, with a full, auditable pressure breakdown and a standards-referenced PDF you can defend in review.
Start your first water pipe sizing calculation