LSTclock vs ZCalcIt
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
LSTclock
This utility app displays local sidereal time for registered locations on iOS, iPadOS, and watchOS. It can also calculate sidereal time and Julian Date for any date and time, and sync locations between devices.
- Local sidereal time display
- Julian Date calculation
- Supports multiple registered locations
- Location sync between iPhone and Apple Watch
- Date and time specific calculations
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LSTclock is an iOS/iPadOS/watchOS app that displays the local sidereal time (LST) at registered location(s). On iOS/iPadOS, it can also calculate LST and Julian Date for any date and time. The list of locations can be synced between iPhone and paired Apple Watch(es).
ZCalcIt
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• Basic add, subtraction, multiply, divide, and power calculations. • Create variables to reuse in calculations. • Library of basic functions: sine, cosine, tangent, and more. • Units: Unit conversion (i.e., linear, time, temperature) functions. • Organized a set of calculations into projects for future references. • Documentation: Complete built-in documentation of all functions with numerous examples to get you started quickly.
Screenshots
Verdict
The clearest difference is update cadence: LSTclock at every 2 months against ZCalcIt's every 11 months. 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. Neither carries in-app purchases, so what you see is what you pay.
LSTclock ships an update every 2 months, ZCalcIt every 11 months. The most recent releases landed on October 24, 2026 and October 27, 2026 respectively.
| Parameter | LSTclock | ZCalcIt |
|---|---|---|
| Price | Free | Free |
| Rating | 3.8 (10 ratings) — better | — |
| Positive reviews | 54.5% of reviews | — |
| Number of ratings | 10 — better | — |
| Update frequency | Every 2 months — better | Every 11 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad, Apple Watch | iPhone, iPad, Mac |
| Requires iOS | 18.0 | 17.2 — better |
| Further details — not scored | ||
| Size | 22 MB | 7 MB |
| Age rating | 4+ | 4+ |
| Developer | Tsuyoshi Sawada | Zynergy Apps |
In-app purchases
LSTclock
No in-app purchases
ZCalcIt
No in-app purchases
Questions
Is LSTclock free?
Is ZCalcIt free?
Do LSTclock or ZCalcIt have ads?
Which is updated more often, LSTclock or ZCalcIt?
Other comparisons
