Calculator + vs Smart Purifier
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Calculator +
This app offers a free basic and scientific calculator with an intuitive interface. It supports fractions, percentages, and advanced editing. Optional upgrades provide specialized calculators for fractions with units, polynomial and linear equation solving, graphing, and geometric shapes.
- Free basic and scientific calculator
- Intuitive interface with equation and result display
- Fraction and percent support
- Advanced editing capabilities
- Polynomial and linear equation solver
- Graphing calculator
- Unit conversion and geometric calculators
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Award winning calculator app for iPad and iPhone. Designed with simplicity, usability and beauty in mind! FEATURES: - Free basic calculator - Free scientific calculator - Elegant & Intuitive interface - Advanced editing by easily going back and forth - Displays both the equation & the result at the same time - Supports Fraction & Percent - Supports many scientific functions If you are looking for more advanced features you can upgrade to one or more of the following: - Fraction Calculator with feet, inches & cm support! - Solving for x with a polynomial Calculator for solving quadratic & cubic equations 2x³ - 4x² - 22x + 24 = 0 - Linear Equations Solver for solving system of linear equations 2x – y = 9 3x + 4y = –14 - Graphing Calculator to find the local min, max & intersection points y = 2x³ – 4x (x² + y²)³ = -27y²x² - Triangle Calculator - Cone Calculator - Arc Calculator - Circle Calculator - Base Converter ( HEX OCT BIN DEC ) - Multiple themes Enjoy the FREE Scientific calculator on your iPhone & iPad. If you like it, support us by upgrading or giving us a positive review. Thanks :) Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Smart Purifier
Monitor and control your Smart Purifier air quality device. View real-time air quality data and adjust settings remotely. Ensure a healthy living environment with this connected appliance management tool.
- Remote device control
- Real-time air quality monitoring
- Device settings adjustment
- Air purification management
- Connected appliance integration
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Ứng dụng giám sát và điều khiển thiết bị Smart Purifier (Thiết bị máy lọc không khí cấp khí tươi Viettel) - sản phẩm của Trung tâm Nghiên cứu thiết bị Y Tế - Tổng công ty Công nghiệp công nghệ cao Viettel (VHT) - Viettel Group
Screenshots
Verdict
The clearest difference is review sentiment: Calculator + at 85% against Smart Purifier's 0%. Calculator + also leads on rating (4.6 vs 1.0) and ratings volume (10K vs 1). Smart Purifier's advantage is in-app purchases (none vs 12) and ads (none vs shown). On price 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. Calculator + sells 12 in-app purchases, starting at $4.99 per month. Smart Purifier asks for nothing beyond the download.
Calculator + holds the better App Store score, 4.6 against 1.0. That said, the two scores are not equally well evidenced: Calculator + has 10K ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 85% of Calculator +'s written reviews are positive against 0% of Smart Purifier's.
Calculator + ships an update every 5 days, Smart Purifier fortnightly. The most recent releases landed on October 18, 2026 and October 1, 2026 respectively.
| Parameter | Calculator + | Smart Purifier |
|---|---|---|
| Price | Free | Free |
| Rating | 4.6 (10K ratings) — better | 1.0 (1 ratings) |
| Positive reviews | 84.9% of reviews — better | 0.0% of reviews |
| Number of ratings | 10K — better | 1 |
| Update frequency | Every 5 days — better | Fortnightly |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 16.4 | 11.0 — better |
| Further details — not scored | ||
| Size | 49 MB | 115 MB |
| Age rating | 4+ | 4+ |
| Developer | xNeat.com | VIETTEL GROUP |
Customer experience
Calculator +
Smart Purifier
Bugs and requests
Calculator +
Reported bugs
5 issues- Fraction calculator has TWO subtraction buttons and NO division button
- Decimals seem to be changed to fraction with no apparent way of changing it back
- Functionality is dropped by forcing you to the main menu every time you open it
- Currency converter broken
- Login screen freezes
Requested features
5 requests- Add mod function
- Add commas
- Add 1/x function
- Support for Retina Display
- Add number 4 with two lines
Smart Purifier
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Calculator +
- Scientific Calculator3 Days trial$4.991 Month
- Calculator7 Days trial$39.991 Year
- Linear Calculator$2.99
- Factoring Calculator$2.99
- Handwriting Calculator$2.99
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- Currency Converter$2.99
- Themes Pack$2.99
- Graphing Calculator$3.99
- Fraction Calculator$3.99
- Scientific Calculator$4.99
- Calculator Plus$4.99
- Calculator$16.99
Smart Purifier
No in-app purchases
Questions
Is Calculator + free?
Is Smart Purifier free?
Which has better reviews, Calculator + or Smart Purifier?
Do Calculator + or Smart Purifier have ads?
Which is updated more often, Calculator + or Smart Purifier?
Other comparisons
