Example Data Table
| Case |
Pipe ID |
Pressure |
Leak Opening |
Coefficient |
Estimated Flow |
| Small service line |
25 mm |
250 kPa |
1.5 mm round hole |
0.62 |
About 0.82 L/min |
| Building supply pipe |
50 mm |
300 kPa |
3 mm round hole |
0.62 |
About 3.40 L/min |
| Cracked pipe |
80 mm |
4 bar |
1 mm by 30 mm slot |
0.60 |
About 49.0 L/min |
Formula Used
The calculator uses the orifice flow model for a pressurized leak.
Leak area: A = πd² / 4 for a round opening.
Slot area: A = width × length.
Flow: Q = Cd × A × √(2ΔP / ρ) × safety factor.
Total flow: multiply Q by the number of leaks.
Volume lost: V = Q × time.
Cost: cost = V × cost per cubic meter.
How to Use This Calculator
Enter the pipe inner diameter and choose its unit.
Select the leak opening type that best matches the damage.
Enter leak size, system pressure, density, coefficient, and duration.
Add number of leaks and cost per cubic meter when needed.
Press Calculate to view the result above the form.
Use Download CSV or Download PDF to save the same result.
Pipe Leak Planning Guide
Why Inner Diameter Matters
A pipe leak starts with area. Inner diameter gives the real flow space inside the pipe. It also gives a useful reference for the leak opening. A small hole may look harmless, yet pressure can push large volumes through it. This calculator compares leak area with full pipe area, so the result is easier to judge.
How Pressure Drives Loss
Pressure is the main force behind leakage. Higher pressure creates higher exit velocity. The orifice equation links pressure, fluid density, discharge coefficient, and opening area. The result is estimated flow rate. The same rate is then extended over the selected time. That gives total volume lost. When a water price is entered, the tool also estimates direct cost.
Choosing Reliable Inputs
Use the actual pipe internal diameter, not the nominal pipe size. Nominal sizes can differ by material and schedule. For a round pinhole, enter leak diameter. For a slot or crack, enter width and length. For uncertain damage, use percent of pipe area. The discharge coefficient adjusts for edge shape. Sharp holes often use about 0.62. Rounded openings can be higher.
Reading The Results
Flow is shown in cubic meters per second, liters per minute, and gallons per minute. Volume is shown for the selected duration. Velocity helps show how aggressive the escaping jet may be. Percent of pipe area shows whether the leak behaves like a tiny defect or a major rupture. Cost shows the visible billing impact, but property damage may be much higher.
Practical Use Cases
Maintenance teams can use the output to rank leaks. Designers can compare pipe sizes and pressure zones. Homeowners can estimate why a meter keeps moving. Construction teams can test temporary lines after pressure checks. The calculator is also useful for training, reports, and quick planning notes.
Important Limits
The result is an engineering estimate. Real leaks may change shape, clog, erode, or flow through soil. Long pipes can have pressure loss before the leak. Air pockets and mixed fluids can change behavior. Use field measurements when safety, structural damage, or high pressure is involved. Always document assumptions beside exported results, so reviewers know measured values and estimates. This supports faster review.
FAQs
1. What does inner diameter mean?
Inner diameter is the open width inside the pipe. It is not always the same as nominal pipe size. Use actual internal diameter when possible.
2. Which pressure value should I enter?
Enter the pressure difference across the leak. For a pipe leaking to atmosphere, use gauge pressure inside the pipe.
3. What discharge coefficient should I use?
A sharp small hole often uses about 0.62. Rounded openings can be higher. Rough cracks may be lower. Use field data when available.
4. Can this estimate water bill loss?
Yes. Enter cost per cubic meter. The calculator multiplies lost volume by that cost. It does not include cleanup or repair costs.
5. Does this handle crack shaped leaks?
Yes. Choose slot or crack. Then enter width and length. The tool uses rectangular area for that opening.
6. Why is fluid density needed?
Density affects exit velocity. Heavier fluids move slower at the same pressure. Water commonly uses about 998.2 kg/m³ near room temperature.
7. Is the result exact?
No. It is an engineering estimate. Real leaks can change shape, clog, erode, or lose pressure through long pipe runs.
8. When should I call a professional?
Call a professional for high pressure, buried leaks, structural damage, gas lines, chemical fluids, or any unsafe operating condition.