# DuctCalc - HVAC Ductulator — Duct sizing, CFM. Buy once.

> Duct sizing, CFM. Buy once. (iPhone/iPad app by Truck and Toolbox.)

- Source: https://appshunter.io/ios/app/ductcalc-hvac-ductulator/id6808448042 (this page in markdown: same URL + `.md`)
- Developer: [Truck and Toolbox](https://appshunter.io/developer/1810936594)
- Category: Utilities, Productivity
- Price: $3.99
- Age rating: 4+
- Requires: iOS 17.0 · 5 MB
- Languages: American English
- Released: 2026-09-15
- Data updated: 2026-10-04

## What is DuctCalc?

Size and check HVAC ductwork with guided steps made for installers, sheet-metal workers, and residential designers. DuctCalc works on iPhone and iPad, and its calculators work without an internet connection.

SIZE DUCTWORK
Enter airflow, then size by design friction or target velocity. Review the exact diameter, recommended standard round size, velocity, friction, and nearby round options. Select up to three rectangular heights for equivalent sizes, set fabrication width increments, and apply a configurable flex-duct factor when your design calls for one.

CHECK AN EXISTING DUCT
Choose round, rectangular, or flat oval. Use known airflow to calculate velocity and friction, or use known velocity to calculate airflow. Add an optional run length to estimate total friction loss. Results also include velocity pressure.

CONVERT DUCT SHAPES AND UNITS
Calculate equivalent round and rectangular dimensions, solve a missing rectangular side, size from an aspect ratio, and find a flat-oval equivalent diameter. Add airflow for a velocity comparison. A separate flex correction helper and converters for airflow, pressure, length, velocity, and friction cover common imperial-to-metric field conversions.

QUICK JOBSITE CALCULATIONS
Estimate airflow from cooling tons, divide system CFM evenly across registers and size each branch, or estimate round and rectangular duct surface area and sheet-metal weight by gauge with a waste allowance.

SAVE, SHARE, AND SET DEFAULTS
Save Size and Check results to searchable local history, revisit or delete saved work, and share calculation text through the iOS share sheet. Set units, rectangular width increment, flex factor, velocity-warning preset, decimal places, and haptics.

PAY ONCE, WORK OFFLINE
No account, ads, in-app purchases, or subscriptions. Calculations, history, and settings are stored locally on your device. Sharing, feedback, rating, and privacy-policy links open only when you choose them.

DuctCalc uses standard ASHRAE equations for clean galvanized duct and standard air. Actual system performance depends on fittings, material, elevation, and installation quality. Sizing shown here is a starting point; verify with an approved design method (for example, ACCA Manual D) and applicable codes.

## Chart rankings

- #185 in Top Paid · Utilities (US App Store)

## Is DuctCalc safe?

Not enough ratings yet to assess DuctCalc.

## Is DuctCalc legit?

DuctCalc - HVAC Ductulator appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for DuctCalc is 65 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0 — 2026-09-15

No release notes.

## More apps by Truck and Toolbox

- [Fence Pro](https://appshunter.io/ios/app/fence-pro/id6745133702)
- [TuneKit](https://appshunter.io/ios/app/tunekit/id6761321611)
- [Cosmic Quarry](https://appshunter.io/ios/app/cosmic-quarry/id6795318764)
- [Tuna Beach Guitar Tuner](https://appshunter.io/ios/app/tuna-beach-guitar-tuner/id6807249559)
- [FrameCalc - Feet Inch Fraction](https://appshunter.io/ios/app/framecalc-feet-inch-fraction/id6808447607)
- [PipeCalc - Pipefitter Offsets](https://appshunter.io/ios/app/pipecalc-pipefitter-offsets/id6808447824)

All apps by Truck and Toolbox: https://appshunter.io/developer/1810936594

## Related topics

[duct sizing](https://appshunter.io/ios/topics/duct-sizing)

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-04.*