# Ductwise: HVAC Duct Calculator — Duct size, CFM, velocity & BTU

> Duct size, CFM, velocity & BTU (iPhone/iPad app by Andrew Putranto.)

- Source: https://appshunter.io/ios/app/ductwise-hvac-duct-calculator/id6820494276 (this page in markdown: same URL + `.md`)
- Developer: [Andrew Putranto](https://appshunter.io/developer/1097285857)
- Category: Utilities, Productivity
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.0 · 20 MB
- Languages: American English
- Released: 2026-11-01
- Data updated: 2026-11-02

## What is Ductwise?

Size ducts in seconds.

Ductwise is a duct size calculator for HVAC techs and installers. Enter CFM and friction rate to get the round duct size, the rectangular equivalent and the air velocity.

FREE TOOLS
- Duct size (round and rectangular), equal-friction method
- CFM and airflow: from a duct and its velocity, a sensible load, tonnage or air changes
- BTU room load estimate
- Duct velocity (fpm), velocity pressure and friction, checked against your own limit

BUILT FOR THE JOB SITE
- Big, high-contrast numbers you can read at arm's length
- Imperial or metric
- Set your friction rate and max velocity once; every tool starts from them
- Works fully offline, with no ads and no account

DUCTWISE PRO (ONE-TIME PURCHASE)
- Superheat and subcooling for R-410A, R-32, R-454B, R-22, R-134a, R-407C and R-404A
- Size every trunk and branch in one job
- Saved jobs and PDF duct schedule

Pay once. No subscription.

The method is shown on every result, so you can check it against the duct calculator you already carry. Results are guidance; verify against your design standard.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Ductwise Pro | $3.99 | one-time |


## Is Ductwise safe?

Not enough ratings yet to assess Ductwise.

## Is Ductwise legit?

Ductwise: HVAC Duct Calculator appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for Ductwise is 75 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 1 release)

### 1.0.0 — 2026-11-01

No release notes.

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All apps by Andrew Putranto: https://appshunter.io/developer/1097285857

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*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 2026-11-02.*