# DuctWise HVAC Duct Calculator — Ductulator, sizing & static > Ductulator, sizing & static (iPhone/iPad app by Yaniv van der Stigchel.) - Source: https://appshunter.io/ios/app/ductwise-hvac-duct-calculator/id6814964642 (this page in markdown: same URL + `.md`) - Developer: [Yaniv van der Stigchel](https://appshunter.io/developer/6791340700) - Category: Utilities, Productivity - Price: $4.99 - Age rating: 4+ - Requires: iOS 17.0 · 6 MB - Languages: American English, French (France), German (Germany), Brazilian Portuguese, Mexican Spanish - Released: 2026-09-24 - Data updated: 2026-10-13 ## What is DuctWise HVAC Duct Calculator? You already know how to size a duct. This agrees with your wheel, and then answers the part the wheel cannot. Type the airflow and the friction rate. DuctWise gives you a round size the supply house actually stocks, the velocity that size will really run at, and the static the whole run will cost you — off the ASHRAE friction chart for galvanised round duct, the same chart the ductulator in your door pocket is printed from. THE PART A WHEEL CANNOT DO The round size was never the hard part. What fits in a 2x10 joist bay is. Tap once and you get every stocked rectangular size that carries the same air, squarest first, with anything past 4:1 flagged before you order it — and the flat-oval sizes beside them, for the spaces where a rectangle will not go. It is equal friction, not equal area. A 20x8 does not carry what its area suggests, because the air drags past more metal on the way through. DuctWise uses Huebscher's equation, so the equivalents are honest. IT KNOWS WHAT THE DUCT IS FOR A bedroom branch and a shop main want very different velocities. Say which one you are running and every size is checked against the design band for that job — in the band, or above it, or below it, with the band drawn so you can see how close to the edge you are. Supply trunk, supply branch, return trunk, return branch, commercial main, commercial branch, commercial return. Typical values from Manual D and ASHRAE Fundamentals, with a line on each saying why the band is where it is. THE REST OF IT Static over the run. Enter the total equivalent length — straight duct plus the fittings — and see what the duct costs you in inches of water, which is the number that has to fit inside the blower table. Altitude correction. Friction loss falls with air density. A job a mile up loses about a sixth less pressure per 100 ft than the chart says, and the app accounts for it. Inches and CFM, or millimetres and litres per second. Friction in in.wg/100ft or pascals per metre. Switch at any time with nothing to re-enter. The friction chart for your airflow, with two sizes either side of the pick, so you can argue with the answer instead of taking it. WHAT IT IS NOT It does not calculate a heat load or a total effective length. It sizes one duct against one target. A whole system still needs Manual J and Manual D, and the job's specification governs. The app says so on its own Reference screen. One payment. No subscription, no account, no ads, and no network connection anywhere in it — which matters in a crawlspace, where there is no signal either. ## Is DuctWise HVAC Duct Calculator safe? Not enough ratings yet to assess DuctWise HVAC Duct Calculator. ## Is DuctWise HVAC Duct Calculator legit? DuctWise HVAC Duct Calculator appears legitimate, with a few gaps. The AppsHunter Legitimacy Score for DuctWise HVAC Duct Calculator is 65 out of 100 points across 7 verification signals from App Store and developer data. ## Version history (last 3 releases) ### 1.1 — 2026-10-06 New: fits the bay. See a to-scale joist bay with the duct shape that fits, or a split. New: static budget. The blower's rated static minus losses gives the friction rate to size at. New: flex or metal, sized with real friction. New: job list with totals and a one-page PDF duct schedule. Fixed a bug where saved friction was reset. ### 1.0.1 — 2026-09-28 New app icon. Small fixes and polish. ### 1.0 — 2026-09-25 No release notes. ## More apps by Yaniv van der Stigchel - [Every Angle](https://appshunter.io/ios/app/every-angle/id6791340698) - [evnt: venue agenda tracker](https://appshunter.io/ios/app/evnt-venue-agenda-tracker/id6792543254) - [DAF Speech Jammer & Fluency](https://appshunter.io/ios/app/daf-speech-jammer-and-fluency/id6809582675) - [SpeedFeed Machinist Calculator](https://appshunter.io/ios/app/speedfeed-machinist-calculator/id6809584773) - [Gift Tracker: Christmas List](https://appshunter.io/ios/app/gift-tracker-christmas-list/id6809765243) All apps by Yaniv van der Stigchel: https://appshunter.io/developer/6791340700 --- *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 2026-10-13.*