Days Between Dates Calculator vs B737 Maintenance Mastermind
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Days Between Dates Calculator
Instantly calculate the number of days, months, and years between any two dates. Features include live current date tracking, inclusive/exclusive counting modes, and saving past calculations. Supports multiple languages and offers a clean, intuitive interface.
- Instant date calculations
- Live current date tracking
- Inclusive & exclusive modes
- Save & review history
- Weekday display
- Tap to copy result
- Multi-language support
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How many days between two dates? Find out instantly with Days Between Dates Calculator — the fastest, simplest way to count days, months, and years between any two dates. INSTANT DATE CALCULATIONS Just pick a start date and an end date. The result updates automatically — no buttons to press. See the total number of days in large, easy-to-read text, plus a detailed breakdown into years, months, and days. LIVE CURRENT DATE TRACKING Toggle "Use Current Date" to always calculate from your chosen start date to today. The result updates in real time — perfect for tracking how many days since an event, or how long you've been on a streak. INCLUSIVE & EXCLUSIVE MODES Switch between inclusive and exclusive counting. Inclusive mode counts both the start and end dates. Exclusive mode counts only the days in between. Great for planning vacations, contracts, deadlines, and more. SAVE & REVIEW HISTORY Save any calculation with a custom title. Revisit saved entries anytime — items with "Use Current Date" enabled will recalculate dynamically so you always see the latest count. WEEKDAY DISPLAY See the weekday name for both the start and end dates at a glance. TAP TO COPY Tap the result to copy the number of days to your clipboard instantly. MULTI-LANGUAGE SUPPORT Available in English, Simplified Chinese, Traditional Chinese, Spanish, Portuguese (Brazil), French, German, Japanese, and Korean. DESIGNED FOR EVERYONE Clean, intuitive interface that follows Apple Human Interface Guidelines. Supports Light Mode and Dark Mode. No ads. No subscriptions. No third-party libraries. Just a simple, reliable date calculator. Perfect for: • Counting days until a deadline or event • Tracking days since a birthday, anniversary, or milestone • Calculating project durations • Planning travel and vacations • Age calculations in days • Contract and legal date counting Thank you for your support! Visit nitrio.com for more apps for your iOS devices.
B737 Maintenance Mastermind
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B737 Maintenance Mastermind is an independent quick-reference and utility app designed to support aircraft technicians, engineers, mechanics, and aviation professionals working with Boeing 737 NG and MAX aircraft. The B737MM app combines fast offline tools with secure premium reference modules, helping users quickly find maintenance-related information, calculations, references, and troubleshooting guidance during study, training, planning, or daily technical routines. FREE TOOLS • MEL Calculator Quick helper for standard dispatch time limit calculations. • Unit Converter Fast conversion of common aviation units, including pressure, temperature, volume, weight, and fuel-related values. • Fuel Calculator Useful fuel uplift and density calculation tool for quick planning and cross-checking. • Abbreviations Dictionary Large searchable glossary of aviation, maintenance, and technical abbreviations. PREMIUM REFERENCE MODULES • Alerts Searchable cockpit alert, status, and message references with related technical context. • Flags Reference guide for PFD, ND, FMC/CDU, and display flags. • BITE Built-In Test Equipment reference module with test access information and related troubleshooting links. • MEL Reference Fast searchable Minimum Equipment List reference support for NG/MAX style workflows. • CDL Reference Configuration Deviation List reference module for missing or deferred aircraft configuration items. • Circuit Breakers / CB ATA-grouped circuit breaker reference with panel-related information. • Lights Cockpit, annunciator, and system light reference module with related system context. • Location Aircraft component, access panel, service panel, antenna, and equipment location references. • STA Map Station, frame, stringer, waterline, and aircraft location reference helper for quick orientation. • Visual Panels Interactive visual reference for cockpit panels and related light/panel locations. • Support & Materials Technical support notes, fastener/material references, practical troubleshooting notes, and maintenance helper information. PREMIUM ACCESS Premium reference modules open with an auto-renewable yearly subscription (with a 3-day free trial for eligible users) or a one-time lifetime purchase, both offered in the app. Payment is charged to your Apple Account at confirmation of purchase. The subscription renews automatically unless it is cancelled at least 24 hours before the end of the current period, and your account is charged for renewal within 24 hours before the end of the current period. You can manage or cancel your subscription in your Apple Account settings at any time after purchase. Use Restore Purchases in the app to restore access on a new device. Some premium content requires internet access for first download, access verification, or content updates. Once downloaded, content is available on the device for fast access. IMPORTANT DISCLAIMER This application is an independent reference and training support tool. It is not official Boeing documentation and is not affiliated with, endorsed by, sponsored by, or associated with The Boeing Company, any airline, aircraft operator, maintenance organization, or aviation authority. The information in this app is provided for educational, training, and general reference purposes only. The official Aircraft Maintenance Manual (AMM), Fault Isolation Manual (FIM), Illustrated Parts Catalog (IPC), Wiring Diagram Manual (WDM), Structural Repair Manual (SRM), and the operator-approved MEL/CDL are the only official sources and must always take precedence. Do not use this application as the sole source for aircraft maintenance actions, dispatch release decisions, operational decisions, or work on an actual aircraft. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://b737mm.com/privacy/
Screenshots
Verdict
The clearest difference is price: B737 Maintenance Mastermind at Free against Days Between Dates Calculator's $2.99. B737 Maintenance Mastermind also leads on update cadence (every 2 days vs every 22 months). Days Between Dates Calculator's advantage is in-app purchases (none vs 2). On ads, 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
B737 Maintenance Mastermind is free to download; Days Between Dates Calculator costs $2.99 up front. B737 Maintenance Mastermind sells 2 in-app purchases, starting at $8.99 per year. Days Between Dates Calculator asks for nothing beyond the download.
Days Between Dates Calculator ships an update every 22 months, B737 Maintenance Mastermind every 2 days. The most recent releases landed on November 3, 2026 and October 31, 2026 respectively.
| Parameter | Days Between Dates Calculator | B737 Maintenance Mastermind |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 5.0 (1 ratings) — better | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 22 months | Every 2 days — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | — |
| Devices | iPhone, iPad | iPhone, iPad |
| Requires iOS | 17.6 — better | 18.0 |
| Further details — not scored | ||
| Size | 1 MB | 10 MB |
| Age rating | 4+ | 4+ |
| Developer | Heng Jia Liang | Nemanja Dimitrijevic |
In-app purchases
Days Between Dates Calculator
No in-app purchases
B737 Maintenance Mastermind
- Premium Yearly3 Days trial$8.991 Year
- Premium Lifetime$17.00





