JSCalculator vs Time Left
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
JSCalculator
This advanced calculator evaluates expressions as you type, eliminating the need for an equals key. It supports complex formulas, variables, and predefined constants, making it ideal for scientific and engineering tasks.
- Instant evaluation as you type
- Formula entry with variables
- Multi-step formulas
- History of entered formulas
- Predefined constants of nature
- Copy and paste functionality
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Not an imitation of a limited stand alone electronic calculator of old. This is a calculator that exploits the power of the device it is running on. It works slightly differently, but it allows for more flexibility. As an example, JSCalculator evaluates what you type without the need of hitting "=" or an enter key. In this calculator, the "=" key is for assigning values to variables, not for telling it to execute a calculation! In JSCalculator, what you enter can be a standard calculation like "1+2", but it can also be much more! JSCalculator was developed by a physicist who needed to be able to enter a short formula on an iOS device, and have it evaluated for various values of some parameters. In addition to predefined functions and the ability to edit even longer or multi-step expressions, this calculator provides a set of the most used constants of nature (in SI units). Short list of the main features: - No enter key. No equal sign that must be pressed to execute a calculation. - What you write is evaluated as you type, and you immediately see the result. - Enter formulas, not just calculations. - Use multi-step formulas with intermediate (algebraic) variables. - Example of a multi-step formula: "p = sqr(a)+b;sin(p)/p" - Every formula you enter is stored, so that you can re-use it the next time you use the calculator. Cycle through all formulas with arrow buttons on the front screen or via standard lists. - Intelligent exponential/engineering notation for the calculated results (optional). - Several predefined mathematical functions. - Predefined constants of nature. - Ability to copy and paste. Ability to copy the result of calculations, or the values of one of the predefined constants of nature. - Numeric keys for typing numbers, predefined functions, or constants, but the standard keyboard will appear when the "T" button is pressed. Any issues or questions? Use our feedback form to tell us about them: http://ivpadev.com/support.html
Time Left
This app helps you visualize the finite nature of your time, displaying the remaining days, months, and years. It encourages a more present and creative life by emphasizing the preciousness of each moment. Your data remains private, with no notifications or ads.
- Displays remaining days, months, and years
- Emphasizes the preciousness of time
- Encourages a happy and creative life
- No notifications, ads, or sign-up
- Private data storage
- Unlockable widgets and customization (Pro)
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No notifications. No ads. No sign-up. Just you and your time. TIME LEFT DESCRIPTION Sometimes life seems really short, and other times impossibly long. This app will help you to emphasize that it’s most certainly finite. Time Left shows you, the days, months, and years you have left and that they are all you have got. Don’t be afraid, that means the only appropriate word to describe your time left is “precious”. So I hope this app will enable you to create a life in which you will be happy and creative. WHAT ABOUT YOUR PRIVACY? I think Privacy is a fundamental human right. To that end, I have designed Time Left from the ground up without any external framework. In this way, your data, like your birthdate, stays entirely private. HOW CAN YOU HELP ME? As I don’t collect any data on this app, to improve it I need your help! You can send me an email to julien@lacroix.dev for any feedback, issues, or bugs on this app or just to say “Hello!”. I answer every email! ********** A special thank you to Wait But Why for this amazing article (https://waitbutwhy.com/2014/05/life-weeks.html). Without their work, this app would not have seen the light of day. ********** TIME LEFT PRO - Unlock widgets & skins. - Unlimited moments. - Live Photos in Life Calendar. - Automatically access all future features and widgets. - Support an indie developer. ********** Terms of Use: https://gettimeleft.app/terms Privacy Policy: https://gettimeleft.app/privacy
Screenshots
Verdict
The clearest difference is price: Time Left at Free against JSCalculator's $0.99. Time Left also leads on update cadence (every 6 days vs every 25 months) and ratings volume (237 vs 2). JSCalculator's advantage is in-app purchases (none vs 5) and rating (5.0 vs 4.6). On ads 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
Time Left is free to download; JSCalculator costs $0.99 up front. Time Left sells 5 in-app purchases, starting at $4.99 per 7 days. JSCalculator asks for nothing beyond the download.
JSCalculator holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: Time Left has 237 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 100% of JSCalculator's written reviews are positive against 73% of Time Left's.
JSCalculator ships an update every 25 months, Time Left every 6 days. The most recent releases landed on October 3, 2026 and October 20, 2026 respectively.
| Parameter | JSCalculator | Time Left |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 5.0 (2 ratings) — better | 4.6 (237 ratings) |
| Positive reviews | 100.0% of reviews — better | 73.5% of reviews |
| Number of ratings | 2 | 237 — better |
| Update frequency | Every 25 months | Every 6 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Free with in-app purchases — better |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15 — better | 17.0 |
| Further details — not scored | ||
| Size | 1 MB | 42 MB |
| Age rating | 4+ | 4+ |
| Developer | Ivan Biaggio | Julien Lacroix |
Customer experience
JSCalculator
Time Left
Bugs and requests
JSCalculator
Not enough reviews yet to summarise bugs or requests.
Time Left
Reported bugs
9 issues- Widget not updating daily after recent updates
- Display text rendering issues (font size problems)
- App fails to load past welcome screen on some devices
- Widget incompatibility with iOS 18.4
- Years and months numbers displaying upside down
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- Days not appearing in display
- Laggy page transitions
- Current day needle stuck and not moving
- Developer unresponsive to support requests
Requested features
11 requests- Lock screen widget support
- Apple Watch widget integration
- Multiple time granularity options (weeks, days, hours)
- Life expectancy limit increased beyond 90 years
- Customizable row lengths in calendar view
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- Auto dark mode for app and widgets
- Specific date countdown feature
- Weekly and monthly visualization options
- Ability to adjust widget size and display metrics
- Calendar view showing weeks per year
- Pan and zoom functionality for overall view
In-app purchases
JSCalculator
No in-app purchases
Time Left
- Per week$4.997 Days
- Annual3 Days trial$17.991 Year
- Per year$17.991 Year
- Lifetime$19.99
- One time$24.99









