ActiveOBD vs TrafoCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ActiveOBD
This app functions as an OBDII scanner, offering specialized support for Subaru vehicles (MY2012+). It provides basic parameter readings for free, with a subscription unlocking advanced features like trouble code reading and data logging.
- OBDII scanning
- Subaru-specific support (MY2012+)
- CVT Oil Temperature reading
- AWD duty (%) parameter reading
- Trouble code reading (full version)
- Data logging (full version)
- Graphs building (full version)
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The OBDII scanner app with a special support of Subaru (MY2012+) make. It's the next-generation product based on our well-known "ActiveOBD for Subaru" app bringing its best features to iOS users. A compatible OBD adapter is required. Premium-level adapters supported (best speed and stability): - OBDLink MX+; - OBDLink CX; - vLinker MC+. Entry-level adapters supported (moderate speed, good stability): - Vgate iCar Pro Bluetooth 4.0 (BLE). Other adapters supported: - Viecar Bluetooth 4.0 (BLE), Vgate iCar Pro WiFi, Veepeak OBDCheck BLE+, KONNWEI. We do NOT support the majority of cheap ELM327 v2.1 clones. The basic free version already includes CVT Oil Temperature, CVT ratio and AWD duty (%) parameter readings and nice gauge screen ! Note: some of these parameters are inaccessible on some model ranges. The full version (subscription) includes extra parameters reading and features, such as graphs building, logging ("premium-level adapter" required), trouble codes reading. Note: for resource consumption optimization reason the data collection for graphs/logging activates upon accessing these functions and terminates with the current app session. Terms of Use (standard Apple Terms of Use / EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
TrafoCalc
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TrafoCalc is a practical transformer calculation tool built specifically for field engineers, commissioning teams, and utility professionals. Designed for real-world use at substations and test sites, TrafoCalc provides fast, reliable calculations without spreadsheets or manual formulas. Key Features • Rated current calculation (HV & LV, 3-phase) • Transformer ratio calculation based on vector group • Full tap-changer support (Tap 1 = highest voltage) • Per-tap voltage and ratio calculation • ±0.5% ratio tolerance range for testing reference • Short-circuit current calculation • Supports common IEC vector groups (Dyn, YNd, Yy) • Clean, offline-ready interface Built for Professionals TrafoCalc follows IEC-based formulas and is suitable for: • Factory Acceptance Tests (FAT) • Site Acceptance Tests (SAT) • OLTC verification • Ratio testing reference • Substation commissioning No ads. No clutter. Just the calculations engineers actually need.
Screenshots
Verdict
The clearest difference is price: ActiveOBD at Free against TrafoCalc's $0.99. ActiveOBD also leads on iOS requirement (13.0 vs 18.2). TrafoCalc's advantage is in-app purchases (none vs 1) and update cadence (every 9 days vs every 3 months). On ads 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
ActiveOBD is free to download; TrafoCalc costs $0.99 up front. ActiveOBD sells 1 in-app purchase, starting at $4.99 per month. TrafoCalc asks for nothing beyond the download.
ActiveOBD ships an update every 3 months, TrafoCalc every 9 days. The most recent releases landed on July 23, 2026 and September 8, 2026 respectively.
| Parameter | ActiveOBD | TrafoCalc |
|---|---|---|
| Price | Free — better | $0.99 |
| Rating | 3.6 (39 ratings) — better | — |
| Positive reviews | 45.5% of reviews | — |
| Number of ratings | 39 — better | — |
| Update frequency | Every 3 months | Every 9 days — better |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Freemium | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPad |
| Requires iOS | 13.0 — better | 18.2 |
| Further details — not scored | ||
| Size | 24 MB | 4 MB |
| Age rating | 4+ | 4+ |
| Developer | Mykhailo Zolotarov | Mohd Dahnial Ismail |
In-app purchases
ActiveOBD
- Full Version Subscription1 Month trial$4.991 Month
TrafoCalc
No in-app purchases









