# G3 - Heat Input Calculator

> G3 - Heat Input Calculator (iPhone/iPad app by G3 Inspection Solutions Ltd..)

- Source: https://appshunter.io/ios/app/g3-heat-input-calculator/id6739266881 (this page in markdown: same URL + `.md`)
- Developer: [G3 Inspection Solutions Ltd.](https://appshunter.io/developer/1858136005)
- Category: Productivity
- Price: Free
- Age rating: 4+
- Requires: iOS 13.0 · 62 MB
- Languages: English
- Released: 2025-03-21
- Data updated: 2026-07-09
- User reviews in markdown: https://appshunter.io/ios/app/g3-heat-input-calculator/id6739266881/reviews.md

## What is G3?

If you run heat input calculations in the field, you already know the problem. Online calculators are rough. Excel sheets break. Doing it by hand mid-inspection wastes time you don't have. 

G3 is the first purpose-built heat input calculator for welding and QC inspectors. 

Enter your voltage, amperage, and distance. Hit start on the built-in arc timer when the arc strikes. Live readout as you weld — see your heat input building in real time. Stop it when the pass is done. Heat input and travel speed calculate instantly — in kJ/mm or kJ/in, your call. 

Built by a working inspector. Designed for real field conditions. 

BUILT FOR 
• CWB certified inspectors (Canada) 
• CWI certified inspectors (USA) 
• CSWIP certified inspectors (International) 
• API 510, 570, 653, and 1169 
• Oil and gas, pipeline, and pressure vessel inspection 
• Structural fabrication and shipyard QC 
 
WHAT IT DOES 

• Built-in arc timer — tap start when the arc strikes, stop when the pass ends 
• Instant heat input and travel speed calculation 
• Selectable weld passes: Root, Hot Pass, Fill, Cap — track the entire weld in one place 
• Imperial and metric (kJ/mm and kJ/in) 
• Fully offline — works on the job site, in the field, underground 
• No login. No account. Free. 
 
WHAT'S COMING 

G3 is the first module in a full QC documentation platform for inspectors — welder profiles, job history, PDF reports, Bluetooth gauge integration, and credential-specific documentation. Free for the core calculator, always. 

What inspectors are saying: 

"Best heat input calculator ever. After using a number of heat input calculators in the field, I stumbled across G3. What a blessing in the field, usable offline, able to add welders for future projects, the ability to speak to the developers to make suggestions. It's the all-in-one tool needed for the inspection realm." 
— 5 stars, App Store, Canada


## Version history (last 5 releases)

### 1.1.6 — 2026-07-06

Updated app listing to better serve welding inspectors. Core calculator unchanged - still free, offline, no login required. More tools coming soon.

### 1.1.5 — 2026-06-05

Updated app listing to better serve welding inspectors. Core calculator unchanged — still free, offline, no login required. More tools coming soon.

### 1.1.3 — 2026-06-04

Updated app listing to better serve welding inspectors. Core calculator unchanged — still free, offline, no login required. More tools coming soon.

### 1.1.2 — 2026-05-13

Free Heat Input Calculator – Easily calculate heat input for welding projects.

### 1.1.0 — 2026-03-13

We have introduced the new design of the app in this version

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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 2026-07-09.*