Unit Converter Engineering Pro vs HydroniCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Unit Converter Engineering Pro
This app provides precise unit conversions for engineers, scientists, and students. It supports over 100 units across 35 categories, including scientific notation and 9-digit decimal precision. The tool works offline and adheres to SI, NIST, and ISO standards.
- Over 100 units in 35+ categories
- Scientific notation support
- 9-digit decimal precision
- SI, NIST, ISO compliant
- Offline functionality
- Specialized units included
Read full descriptionHide full description
Unit Converter Engineering Pro – The ultimate tool for engineers, scientists, and students who need precise and fast unit conversions. Easily convert between over 100 units across more than 35 categories commonly used in engineering, physics, chemistry, and mathematics. Perfect for professionals, researchers, and students who want a reliable, professional-grade converter at their fingertips. Included categories: • Acceleration • Angle • Area • Specific Heat • Electric Charge • Heat Transfer Coefficient • Length • Concentration • Thermal Conductivity • Physical Constants • Density • Diffusivity • Energy • Heat Flux • Force • Illuminance • Luminance • Mass • Moment / Torque • Power • ppm / ppb / ppt / % • SI Prefix • Pressure • Radiation – Activity • Radiation – Dose • Radiation – Exposure • Radiation – Equivalent Dose • Time • Volume • Velocity / Speed • Viscosity • Volume Flow Rate • Voltage / Electric Potential • Frequency • Temperature Key Features: • Supports scientific notation for extreme precision • Fully compliant with SI, NIST, and ISO standards • 9-digit decimal precision for engineering-grade accuracy • Fast and intuitive interface • Works offline – no internet required • Includes rare and specialized units often missing from other converters • Made by engineers, for engineers Simplify your work, save time, and ensure accuracy with Unit Converter Engineering Pro - your professional unit conversion companion. EULA: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
HydroniCalc
Read full descriptionHide full description
HydroniCalc brings together 23 hydronic calculators for heating engineers and installers of water-based heating systems. Everything runs in metric units, offline, and without an account. The calculators are grouped into four families: • Basic hydraulics and pipework: power, flow and temperature difference, diameter and velocity, linear and fitting pressure losses. • Valves, balancing and circulator: the Kv / flow / pressure-drop relationship, valve sizing, balancing, and the pump operating point. • Pressurization, volumes and separation: fill pressure, water expansion, expansion vessel, and system volumes. • Radiators and underfloor heating: radiator output correction, sizing, and underfloor loop length. Each calculator shows the values to enter and displays the result as soon as the required data is valid. An info button explains the purpose of the calculation, the expected inputs, the method, the results, and the usage limits. Built-in Kv tables: look up the Kv values published by manufacturers (manufacturer, product, and generation), then copy a value to paste into your calculation. The tables never fill a calculation automatically; the value is always typed or pasted into the field. Recent calculations: your ten most recent successful calculations are stored locally, so you can find them again and resume them with their values. Eleven calculators are free to use. A single, non-subscription purchase permanently unlocks the other twelve for the Apple account used. If a purchase isn’t recognized, “Restore Purchases” asks the App Store to sync it again.
Screenshots
Verdict
The clearest difference is iOS requirement: Unit Converter Engineering Pro at 13.0 against HydroniCalc's 17.0. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Unit Converter Engineering Pro sells 2 in-app purchases, starting at $5.99 per 7 days and HydroniCalc sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
| Parameter | Unit Converter Engineering Pro | HydroniCalc |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Number of ratings | 1 — better | — |
| Update frequency | Weekly | — |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 13.0 — better | 17.0 |
| Further details — not scored | ||
| Size | 77 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Kaiguri Tech | Eric Chmara |
In-app purchases
Unit Converter Engineering Pro
- 3-Day Trial3 Days trial$5.997 Days
- Yearly Plan$19.991 Year
HydroniCalc
- Unlock All Calculators$12.99





