Duct Calculator is a specialized HVAC utility for engineers and technicians to calculate duct dimensions and airflow values on iOS.
The App DNA
What makes this app unique?
The app removes the need for manual slide rules or complex spreadsheets during on-site ventilation design and installation work.
For HVAC engineers, designers, and installation technicians requiring on-site ventilation calculations.
What does it look like?
Key features
Calculates required duct dimensions using CFM and FPM inputs for rectangular and circular ducts, serving as a core utility for HVAC design.
Determines CFM and FPM values to verify ventilation system performance on-site.
Lifetime purchase option to remove advertisements, targeting professionals seeking a permanent utility tool.
How much does it cost?
The freemium model relies on a single lifetime IAP to remove ad-inventory, targeting professionals seeking a permanent utility tool.
Velocity
Dormant developmentopaqueShow more...
Duct Calculator has seen no development activity for over eight months, with the latest release occurring on December 24, 2025. The app currently sits in a zombie state with no evidence of ongoing maintenance or feature updates. Given the lack of recent version history, there is no indication of active development or support for the platform.
Who built it?
Sachinbhai Surani
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Resistor Color Code Calc.User Sentiment
What do users think recently?
How are ratings & reviews evolving?
Not enough recent reviews to extract reliable themes yet.
Read the full review analysisCompetition
Competitive landscape for Duct Calculator.
How's the Productivity market?
Duct Calculator occupies a narrow productivity niche for HVAC professionals. With only three ratings recorded, the app lacks the social proof or chart velocity of broader engineering utilities.
Read the market outlookThe rivals identified
Unlock the deeper market read.
Access the full report for freeThe Analyst's Read
Key takeaways for Duct Calculator.
Where is it heading?
The HVAC utility market is consolidating around tools that integrate project management with technical calculations. Duct Calculator's current maintenance-only trajectory leaves it exposed to competitors that offer more comprehensive workflow support.
- The eight-month development gap suggests a maintenance-only posture, which limits the app's ability to capture new professional segments.
The SWOT
- Specialized HVAC calculation logic provides direct utility for on-site design
- Dual support for rectangular and circular duct sizing covers primary standards
- Material-cost estimation integration captures workflow overlap with project bidding
- Offline-first performance serves construction environments with poor connectivity
Next best moves
Ship project-save functionality because it is the top friction point for on-site technicians → increase session frequency
The counter-intuitive read
The app's lack of cloud-sync is a feature in construction environments with zero-connectivity…
Read the full takeSince the last report: The app remains in a maintenance-only state, but the competitive assessment has sharpened to identify the lack of project-save functionality as a critical barrier to professional retention.
Bottom line
Duct Calculator provides a stable, specialized utility for HVAC professionals, but the lack of active development limits its long-term retention potential.
Unlock 2 critical frictions, 2 market threats and the analyst’s take.
Access the full report for freeFAQ
Is Duct Calculator suitable for professional HVAC design?
Does Duct Calculator work offline?
What is the difference between the free and paid versions?
Sources
- [1] App Store, source
Report last updated