# Quel — Engineering Sizing Toolkit

> Engineering Sizing Toolkit (iPhone/iPad app by Guillermo Alvarado.)

- Source: https://appshunter.io/ios/app/quel/id6752804071 (this page in markdown: same URL + `.md`)
- Developer: [Guillermo Alvarado](https://appshunter.io/developer/1841024589)
- Category: Productivity, Utilities
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.6 · 7 MB
- Languages: American English
- Released: 2025-09-24
- Data updated: 2026-05-15
- User reviews in markdown: https://appshunter.io/ios/app/quel/id6752804071/reviews.md

## What is Quel?

Quel is your all-in-one engineering toolkit for instrumentation and controls.

Designed for process engineers, control engineers, and instrumentation specialists, Quel brings powerful sizing and calculation tools into one streamlined app. Whether you're working on valves, orifice plates, or temperature sensors, Quel helps you size, calculate, and verify with speed and accuracy.

KEY FEATURES

• Control Valve Sizing – Quickly determine Cv, flow conditions, and check for subcritical or critical operation.

• Valve Performance Calculator – Evaluate installed gain, rangeability, and operating point across the full stroke range.

• Orifice Plate Sizing – Built-in ISO 5167 calculations for DP, Beta ratio, and flowrate in engineering units.

• Temperature Sensors – RTD and thermocouple resistance and millivolt reference tables for common sensor types.

• Unit Conversions – Instant conversions across pressure, temperature, flow, and volume to simplify day-to-day calculations.

• Save & Export – Save calculation results to history, export as PDF or text for documentation and field reports.

• Engineering References – Quick guides and formulas used in the field for sizing and troubleshooting.

WHY QUEL?

• Fast & Reliable – Save time in the field or office with ready-to-use sizing tools.

• Accurate – Built around standard engineering methods (ISA, IEC, API, ISO, ASME).

• Practical – Designed by engineers, for engineers, with workflows that match real projects.

• Portable – A professional-grade toolkit in your pocket, whether you're commissioning, troubleshooting, or reviewing designs.

With Quel, you work smarter and more confidently on process control projects, knowing your sizing and calculations are consistent with industry standards.

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Quel Yearly Plan | $69.99 | per year |
| Quel Monthly Plan | $9.99 | per month |



## Version history (last 4 releases)

### 1.3 — 2026-03-23

Version 1.3 brings significant improvements and new features:

• Dark theme – Consistent dark UI across all screens for reduced eye strain in the field.
• Save & Export – Save any calculation to history and export results as PDF or plain text.
• Orifice Plate PDF Export – Full calculation report export directly from the orifice plate screen.
• Reset / Clear Inputs – One-tap reset button on all calculator screens to quickly start a new calculation.
• Done button on keyboard – Dismiss the keypad easily from all numeric input fields.
• ASME B36.10M pipe database – Real Schedule 40 pipe ID lookup replaces estimated fudge factors.
• Unit preference memory – Pressure and temperature unit selections are remembered between sessions.
• Vendor quote dropdowns – Body rating, end connection, and plate material now use standard selection lists.
• Haptic feedback – Tactile response on key interactions throughout the app.
• Bug fixes and performance improvements.

### 1.2 — 2025-10-01

•	Performance improvements for faster calculations
	•	Bug fixes and stability updates
	•	Improved accuracy in valve and flow sizing formulas
	•	Enhanced unit conversion tool

### 1.1 — 2025-09-28

•	Performance improvements for faster calculations
	•	Bug fixes and stability updates
	•	Improved accuracy in valve and flow sizing formulas
	•	Enhanced unit conversion tool
	•	UI updates for clearer navigation

### 1.0 — 2025-09-23

No release notes.

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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 2026-05-15.*