Enter pipe size and velocity to compute flow. Adjust for pressure, temperature, and gas type. Download clean reports for permits, crews, and audits easily.
| Case | Diameter | Velocity | Pressure | Temp | Gas | Line Flow (m³/h) | Mass Flow (kg/h) | Std Flow (Sm³/h) |
|---|---|---|---|---|---|---|---|---|
| A | 100 mm | 12 m/s | 200 kPa (g) | 25 °C | Air | 339.29 | ~1430 | ~898 |
| B | 2 in | 35 ft/s | 30 psi (g) | 80 °F | Natural gas | ~51.0 | ~40 | ~131 |
| C | 150 mm | 8 m/s | 101.3 kPa (a) | 20 °C | Nitrogen | ~407 | ~498 | ~407 |
Accurate flow estimates help crews size temporary lines, validate purge plans, and document commissioning checks. This calculator converts field inputs into line flow, mass flow, and standardized flow, making records consistent across teams and subcontractors.
The tool starts from velocity and pipe inside diameter. It computes cross‑sectional area and then volumetric flow along the line. That output is useful for ventilation, inerting, and utility distribution planning. When pressure and temperature are provided, it estimates density using an ideal‑gas approach and a compressibility factor, enabling mass flow reporting.
Use gauge pressure when readings come from a typical site regulator or manifold. Add local atmospheric pressure to reach absolute pressure, because density depends on absolute values. Enter flowing gas temperature, not shaded ambient air. Select a common gas or enter a custom molar mass when specifications vary or blended fuels are used.
Many permits and supplier tickets reference standard conditions. Standard volumetric flow scales the measured line flow to an agreed pressure and temperature, allowing like‑for‑like comparisons between days, meters, and locations. It also supports normalized consumption baselines for temporary generators or curing enclosures. Keep standard conditions consistent within a project package.
Confirm diameter is an inside value and verify velocity assumptions with spot readings when possible. If results look high, review units, pressure type, and Z before changing field settings. For long runs, remember this calculator does not model pressure drop; pair it with a sizing method when needed. Use the CSV for logs and the PDF for inspection files, handover binders, and contractor sign‑off.
Line flow is the actual volumetric flow in the pipe at your entered pressure and temperature. It is useful for checking capacity, purge duration estimates, and temporary supply planning on site.
Gas density depends on absolute pressure, not gauge. If you enter gauge pressure, the calculator adds atmospheric pressure to obtain absolute pressure before applying the gas law.
Use Z = 1.0 for low‑pressure, preliminary work. For higher pressures or non‑ideal gases, use a vendor chart or equation of state value that matches your gas and conditions.
Use standard flow when permits, billing, or specifications reference standard conditions. It normalizes flow to the standard pressure and temperature so readings from different days or meters can be compared.
No. It calculates flow from velocity and diameter and does not model friction losses, fittings, elevation, or regulator behavior. For sizing, use a pressure‑drop method and then verify flow targets here.
Enter the inside diameter of the flow path. For steel pipe, use the schedule ID rather than the nominal size. For hoses or ducts, measure the internal bore where flow actually occurs.
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.