# QTJTCalculator — QT Interval Calculator > Educational calculator for QTc and JTc interpretation with QRS duration adjustments. (iPhone/iPad app by Keyvon Rashidi.) - Source: https://appshunter.io/ios/app/qtjtcalculator/id6754206991 (this page in markdown: same URL + `.md`) - Developer: [Keyvon Rashidi](https://appshunter.io/developer/1825970126) - Category: Education, Utilities - Price: Free - Rating: 5.00/5 from 2 App Store ratings - Age rating: 4+ - Requires: iOS 26.0 · 2 MB - Languages: English - Released: 2026-04-27 - Data updated: 2026-08-13 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/qtjtcalculator/id6754206991/reviews.md ## What is QTJTCalculator? QTJT Calculator is an educational calculator designed to streamline QTc and JTc interpretation, especially when QRS duration may affect repolarization assessment. The app allows users to enter sex, QT interval, optional QRS duration, and either heart rate or RR interval. If heart rate is entered, RR is automatically calculated; if RR is entered, heart rate is automatically calculated. The app then applies a structured correction workflow and displays calculated outputs in a clean, easy-to-read interface. Key features include: • Automatic HR ↔ RR conversion • QTc calculation using Hodges and Framingham correction • Bogossian QTm adjustment when QRS is wide • Rautaharju bivariate QTc correction using QT, RR, QRS, and sex-specific constants • JTc calculation using Hodges and Framingham correction when QRS ≥ 110 ms • Clear abnormal-value highlighting • Instructions and formula reference built into the app • For educational use only This app is based on correction methods discussed in the literature for QT assessment in the setting of ventricular conduction delay or pacing. When QRS is widened, the measured QT interval may appear prolonged because the QRS duration itself contributes to QT length. QT/JT Correction helps demonstrate practical approaches to adjusting for this issue, including QTm modification and JT-based correction. The app also avoids reliance on the Bazett correction, which can overestimate QTc at higher heart rates and underestimate QTc at lower heart rates. Instead, it focuses on Hodges, Framingham, Bogossian, and Rautaharju-based approaches. The app is intended for educational purposes only. It is not a medical device, does not provide clinical recommendations, and should not be used for diagnosis, treatment, medication decisions, or patient care. Results should always be interpreted in the context of clinical judgment, institutional guidance, and validated clinical references. ## Key features - Automatic HR ↔ RR conversion - QTc calculation (Hodges, Framingham) - JTc calculation (Hodges, Framingham) - Bogossian QTm adjustment for wide QRS - Rautaharju bivariate QTc correction - Abnormal value highlighting - Built-in instructions and formulas ## Frequently asked questions about QTJTCalculator ### What is QTJTCalculator used for? QTJTCalculator is an educational tool designed to help users interpret QTc and JTc intervals on ECGs. It specifically aids in assessing repolarization when QRS duration may influence the results. ### What correction methods does QTJTCalculator use? QTJTCalculator employs several correction methods including Hodges, Framingham, Bogossian (for QTm adjustment), and Rautaharju bivariate correction. It avoids the Bazett correction, which can be less accurate at certain heart rates. ### Can QTJTCalculator be used for medical diagnosis? No, QTJTCalculator is strictly for educational purposes. It is not a medical device and should not be used for diagnosis, treatment decisions, or patient care. All results require interpretation within a clinical context. ### How does QTJTCalculator handle QRS duration? The app allows users to input QRS duration and applies specific adjustments like Bogossian QTm and Rautaharju bivariate correction when the QRS is widened (≥ 110 ms). It also calculates JTc using Hodges and Framingham corrections in these cases. ### What information do I need to enter into QTJTCalculator? You need to enter the patient's sex, the measured QT interval, and either the heart rate or the RR interval. Optionally, you can also input the QRS duration for more advanced calculations. ### Is QTJTCalculator available on Android devices? Based on the provided data, QTJTCalculator is currently supported on iPhone devices. Information regarding Android availability is not specified. ### How often is QTJTCalculator updated? The app was last updated on April 28, 2026, with version 1.1. This indicates a recent update, suggesting ongoing development and maintenance. ### What is the user feedback on QTJTCalculator? QTJTCalculator has received a perfect rating of 5.0 stars from 1 review, indicating a highly positive initial user reception. ## Version history (last 2 releases) ### 1.1 — 2026-04-28 Minor Bug Fixes ### 1.0 — 2026-04-27 No release notes. ## More apps by Keyvon Rashidi - [HemoScopeCVICU](https://appshunter.io/ios/app/hemoscopecvicu/id6754748124) - [2PD](https://appshunter.io/ios/app/2pd/id6761318358) - [JPal1.0](https://appshunter.io/ios/app/jpal10/id6761690780) - [NumeriFaceLive](https://appshunter.io/ios/app/numerifacelive/id6763707742) All apps by Keyvon Rashidi: https://appshunter.io/developer/1825970126 --- *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 2026-08-13.*