ZoneClock vs Flicker Insight
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ZoneClock
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ZoneClock helps you instantly convert time across time zones with a clean, minimalistic UI. Simply enter a time in one location, choose another city, and see the exact local time immediately. Designed for travel, remote teams, and anyone working across time zones, with full offline support.
Flicker Insight
Detects imperceptible light flicker from various sources like screens and bulbs that can cause eye strain. Offers detailed metrics, ambient light and color temperature estimates, and generates exportable reports. Prioritizes user privacy with offline functionality and no ads.
- Quick flicker test with camera
- Eye comfort assessment
- Detailed flicker metrics
- Ambient illuminance estimate
- Color temperature estimate
- PDF report generation
- Offline functionality
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Desk lamps, eye-care lamps, LED bulbs, computer monitors, and smartphone screens may appear steady, while actually producing brightness fluctuations—flicker—that are difficult to detect with the naked eye. Prolonged exposure to flickering light may contribute to eye fatigue, eye strain, headaches, or even dizziness. This app helps you detect flicker that may otherwise go unnoticed. 【QUICK FLICKER TEST】 Point your camera at a light source or screen. The app collects adaptive samples at multiple shutter speeds for about 3 seconds and continuously updates the screening result. • Screening result: Flicker detected / No significant flicker detected / Unable to determine • Eye comfort assessment: Low, medium, or high risk based on the measured flicker level • Detailed metrics: Flicker index, modulation depth, dominant frequency, and brightness waveform 【MORE THAN FLICKER DETECTION】 • Ambient illuminance estimate: Provides an approximate brightness range to help you assess whether the environment is suitable for visual tasks. • Color temperature estimate: Provides an approximate color temperature for reference. 【EXPORT AND SHARE】 Generate a PDF report containing the waveform, frequency spectrum, light source image, and test conclusion, or export the raw data as a CSV file. 【PRIVACY FIRST, FULLY OFFLINE】 • No ads, no analytics SDKs, and no account required. • The app does not actively connect to the internet. All data remains on your device. • Videos created during measurement are processed temporarily and deleted immediately after analysis. Only measurement results and notes are retained. • You can clear all locally stored data at any time from Settings. 【AVAILABLE IN 12 LANGUAGES】 Simplified Chinese, Traditional Chinese, English, Japanese, Korean, French, German, Spanish, Portuguese, Russian, Arabic, and Hindi. 【IMPORTANT NOTICE】 This app provides consumer-grade screening of lighting conditions. Results may be affected by your phone camera’s frame rate, exposure, rolling shutter, and ambient light. It is not a substitute for professional photometric testing, standards compliance certification, or medical diagnosis. Privacy Policy: https://wwmmkk.github.io/Flicker-Insight/Privacy%20Policy Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Screenshots
Verdict
The clearest difference is price: ZoneClock at Free against Flicker Insight's $0.99. ZoneClock also leads on in-app purchases (none vs 2) and iOS requirement (16.6 vs 18.0). Flicker Insight's advantage is update cadence (every 2 days vs weekly). 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
ZoneClock is free to download; Flicker Insight costs $0.99 up front. Flicker Insight sells 2 one-off in-app purchases. ZoneClock asks for nothing beyond the download.
ZoneClock ships an update weekly, Flicker Insight every 2 days. The most recent releases landed on November 9, 2026 and November 13, 2026 respectively.
| Parameter | ZoneClock | Flicker Insight |
|---|---|---|
| Price | Free — better | $0.99 |
| Rating | — | 5.0 (1 ratings) — better |
| Positive reviews | — | 60.0% of reviews |
| Number of ratings | — | 1 — better |
| Update frequency | Weekly | Every 2 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Paid |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 16.6 — better | 18.0 |
| Further details — not scored | ||
| Size | 9 MB | 212 MB |
| Age rating | 4+ | 4+ |
| Developer | Andrei Lupanin | 名楷 王 |
In-app purchases
ZoneClock
No in-app purchases
Flicker Insight
- A Popsicle$0.99
- A Coffee$2.99









