Plumbing Calculators Australia
Stop mucking around with pen and paper. Fast, accurate, AS/NZS 3500 compliant calculators built for Aussie plumbers. Size pipes, check flows, and sort your drainage grades in seconds on site.
Water Pipe Sizing
Size water supply pipes to AS/NZS 3500.1.
Water Flow Rate
Calculate flow rates in L/s or L/min.
Fixture Units
Calculate probable simultaneous demand (PSD).
Water Pressure Drop
Calculate friction loss in pipework runs.
Hot Water System Sizing
Size hot water units based on daily usage.
Drainage Calculator
Size sanitary drainage grades and pipes.
Stormwater Calculator
Size downpipes, eaves gutters, and drains.
Natural Gas Pipe Sizing
Size gas lines to AS/NZS 5601.1.
LPG Gas Pipe Sizing
Size LPG pipework and regulators.
Rainwater Tank Size
Calculate tank sizes for catchment areas.
Grease Trap Sizing
Size passive grease arrestors for commercial.
Septic Tank Sizing
Calculate septic capacities to AS/NZS 1547.
Backflow Prevention
Select the right backflow device hazard rating.
Pipe Volume
Calculate litres contained in a pipe run.
Pipe Fall Calculator
Find exact invert levels and pipe grades.
Pump Head
Calculate total dynamic head for pumps.
Roof Runoff
Calculate catchment areas and flow rates.
Pipe Heat Loss
Determine insulation requirements for hot water.
Finally, plumbing calculators that actually work for Australian trades. No more converting US gallons, PSI, or dealing with tools that don't match our local standards. Built for the tools, by guys who know the trade.
Why Aussie Plumbers Need Local Tools
If you're sick of downloading an app only to find it uses American pipe sizes and imperial units, you're not alone. When you're out on site roughing in a stack or trying to tee off a main, you need tools that speak our language. That means metric units—litres per second (L/s), kilopascals (kPa), and millimetres (mm)—and calculations that strictly follow the Australian Standards.
Our calculators are built specifically around AS/NZS 3500 (Plumbing and Drainage) and AS/NZS 5601 (Gas Installations). Whether you're sizing copper pipe for a rough-in, calculating the required fall for a boundary trap, or sizing up a stormwater run, these tools give you the right numbers fast, so you can get back to the job and avoid defects.
Who These Calculators Are Built For
- Licensed Plumbers: Double-check your numbers before running a line or sizing a pressure pump.
- Gasfitters: Ensure your gas line sizing meets AS/NZS 5601.1 without flicking through the book.
- Apprentices: Learn how to properly calculate probable simultaneous demand (PSD) and pipe grades.
- Drainers: Work out your invert levels and required falls for sanitary and stormwater drainage.
- Hydraulic Consultants: Quickly rough out capacities during the early stages of a build.
A Better Workflow On Site
Using our tools changes how you work on site. It stops you second-guessing your pipe sizes when the inspector rocks up. Here's how it normally plays out on a commercial rough-in or a big residential job:
- Determine Demand: Use the Fixture Unit Calculator to find the total probable simultaneous demand for the property.
- Check Flow Rates: Punch in your numbers to the Water Flow Rate Calculator to see exactly what you'll get at the tap.
- Size the Pipe: Run those figures through the Water Pipe Sizing tool to get the right copper or PEX size to maintain mains pressure without crazy friction loss.
- Sort the Drainage: Jump into the Pipe Fall Calculator to nail your invert levels and ensure your sanitary drainage grades comply with AS/NZS 3500.2.
No guesswork, no thumbing through a battered copy of the standards in the front seat of the ute. Just punch in your measurements and get the answers you need to pass inspection and leave a quality job.