J1 PRODesigned for Engineers. Built for Excellence.
HVAC, electrical, plumbing and civil calculators with formulas and PDF reports – plus free PDF tools.
Popular calculators
Calculators by category
Every calculator shows its formula and method, works in SI or IP units, and makes a PDF report.
Loads & capacity
3
Air distribution & ventilation
9
Air properties
2
Water systems & utilities
9
Results are for preliminary design and engineering review. Verify final selections against project specifications, applicable codes and manufacturer data.
Made for checking, not guessing
Each step is shown with the numbers filled in, so you can check it.
Based on ASHRAE, IEC, BS and UAE plumbing codes – listed under every calculator.
Inputs, steps and results in a clean report for your file.
No sign-up. The app also works offline.
43 engineering calculators · 10 PDF tools · 7 design guides
All these tools on your phone – works offline, saves projects and shares PDF reports.
Learn the method behind the numbers
Short, practical design guides, each linked to the calculator that does the work.
- How to calculate duct external static pressure (ESP) →
- Duct sizing by the equal friction method →
- Cooling load calculation: rules of thumb vs. a proper estimate →
- Chilled water flow rate from cooling capacity →
- Psychrometrics basics for HVAC engineers →
- Fan motor sizing from airflow and static pressure →
- Bar bending schedule (BBS) basics →
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