Comparison

Date and time calc vs Carbon Notes

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Date and time calc

Easily calculate the difference between dates or add/subtract time intervals. This utility app simplifies date and time arithmetic with straightforward operations.

Highlights
  • Date difference calculation
  • Date addition and subtraction
  • Time difference calculation
  • Time addition and subtraction
Features
Read full description

This is a convenient app that makes date and time calculations easy. With simple operation, you can quickly perform the calculations you need. # Features - Date difference calculation - Date addition and subtraction - Time difference calculation - Time addition and subtraction

About

Carbon Notes

Features
Read full description

Carbon is a markdown-focused note-taking app designed for seamless organization of your ideas, tasks, and knowledge. With powerful markdown support and AI-powered tools, Carbon transforms how you capture and develop your thoughts. Unlock one-tap AI for your notes: Use our keys for $20/mo or use your OpenAI, Claude, or Open Router API keys for $5 (one-time unlock) This app supports iPhone, iPad, and Mac OS KEY FEATURES: - Powerful Markdown Support: Write and format your notes with intuitive markdown syntax. Carbon provides real-time preview and styling for a distraction-free writing experience. - AI-Powered Assistance: Leverage AI to enhance your writing with smart tools that can summarize, expand, polish, translate, and transform your content with just a tap. - Intelligent Tagging System: Organize your notes with an advanced tagging system that automatically recognizes hashtags in your content and creates hierarchical tag structures. - Robust Search: Find exactly what you need with our powerful search engine that indexes note content, titles, and tags for lightning-fast results. - Complete Privacy: Your data belongs to you. Carbon supports end-to-end encryption to protect your sensitive notes with military-grade security. - Seamless iCloud Sync: Access your notes across all your Apple devices with reliable CloudKit synchronization that works silently in the background. - Clean, Customizable Interface: Focus on your writing with a distraction-free interface featuring multiple themes and typography options. - Export Flexibility: Share your notes in multiple formats including Markdown, Text, HTML, PDF, and JSON. - Deep Organization: Create a personalized knowledge base with nested tags, favorites, smart collections, and custom filters. - Distraction-Free Writing: Enter a focused writing state with Carbon's minimal interface and keyboard shortcuts. - Markdown Import/Export: Easily bring in existing markdown files or export your notes for use in other applications. - Version History: Never lose important changes with automatic versioning of your notes. - Customizable Themes: Choose from light and dark themes, or customize colors to match your style. - Secure Biometric Authentication: Protect your notes with Face ID, Touch ID, or passcode authentication. CARBON IS PERFECT FOR: - Writers who need a clean environment for drafting and organizing their work - Students taking lecture notes and organizing course materials - Developers documenting projects and code snippets - Researchers collecting and connecting ideas - Professionals managing meeting notes and action items - Anyone looking to build a personal knowledge management system Carbon strikes the perfect balance between simplicity and power. The interface stays out of your way when you want to write, while offering powerful tools when you need them. Advanced features include batch operations, smart lists, custom AI prompts, note encryption, advanced search filters, and multiple export options to fit into any workflow. Your data is yours - Carbon is designed with privacy at its core. Your notes are stored locally and can be optionally encrypted and synced via iCloud. We never collect your notes or personal information. Whether you're capturing quick thoughts, writing detailed documents, or building a complete knowledge base, Carbon provides the tools you need to organize your digital life. Download Carbon today and experience the perfect balance of simplicity, power, and privacy in note-taking. PREMIUM FEATURES (available via subscription or one-time purchase): - AI-powered writing responses - OpenAI key support - Claude key support - Open Router key support Carbon respects your privacy and does not collect personal data or tracking information. Terms and Conditions: https://basicarcana.com/apps/carbon/legal Privacy Policy: https://basicarcana.com/apps/carbon/privacy Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

Date and time calc4 screens
Carbon Notes4 screens

Verdict

The call

The clearest difference is in-app purchases: Date and time calc at none against Carbon Notes's 2. Carbon Notes's advantage is ads (none vs shown) and update cadence (every 3 weeks vs every 16 months). On price, device support and iOS requirement 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Carbon Notes sells 2 in-app purchases, starting at $19.99 per month. Date and time calc asks for nothing beyond the download.

UpkeepUpdate frequency

Date and time calc ships an update every 16 months, Carbon Notes every 3 weeks. The most recent releases landed on July 23, 2026 and September 10, 2026 respectively.

Scorecard3 real differences · 5 level
Date and time calc versus Carbon Notes: the parameters behind the verdict, then further details
ParameterDate and time calcCarbon Notes
PriceFreeFree
Positive reviews23.1% of reviews—
Update frequencyEvery 16 monthsEvery 3 weeks — better
AdsYesNo — better
In-app purchasesNo — betterYes
MonetizationAd-supported—
DevicesiPhone, iPodiPhone, iPad
Requires iOS17.617.6
Further details — not scored
Size6 MB12 MB
Age rating4+4+
DeveloperOsamu IshigamiYMMV

In-app purchases

None

Date and time calc

No in-app purchases

2 purchases

Carbon Notes

Subscriptions1
  • Pro$19.991 Month
One-time1
  • AI Unlock$4.99

Questions

Is Date and time calc free?
Date and time calc is free to download, with no in-app purchases.
Is Carbon Notes free?
Carbon Notes is free to download, with in-app purchases available.
Do Date and time calc or Carbon Notes have ads?
Date and time calc shows ads; Carbon Notes does not.
Which is updated more often, Date and time calc or Carbon Notes?
Date and time calc ships an update every 16 months, and Carbon Notes every 3 weeks. Most recently, Date and time calc was updated on July 23, 2026 and Carbon Notes on September 10, 2026.

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