60
BU Score
Solid
Extreme Kalender
✍️ bumetric analysis
“
Extreme Kalender is an iOS app from Birdsoft LLC in the Business category, currently rated 4.3★ across 24 ratings. Initial signal reads as mixed reviews: supporters praise core features while critics cite stability and value gaps.
Our BU Score puts it at 60: Solid (established niche player). For a Business app, that means established niche player.
Track changes month-over-month in the Performance section below: live snapshot history and revenue forecast included.
📊 Performance Tracking LIVE
Loading…
Rating
—
Reviews
—
Forecast Revenue / mo
—
Snapshots tracked
0
since first record
Range:
💰 Forecast Revenue / mo
MODELRevenue forecast computed from BU's 234 trigger model on each snapshot. Calibrated against ground-truth from 58 verified-revenue apps.
🔬Forecast Breakdown — Why This Estimate?Top 9 of 9 triggers
Our ML model uses 200+ signals from public data. These are the most influential for this app:
| Paid app ($0.00)METRIC | +$2,800 | |
| bugsREVIEW | −$1,800 | |
| 5 starREVIEW | +$1,800 | |
| excellent appREVIEW | +$1,500 | |
| Mature app (15y old)METRIC | +$1,500 | |
| highly recommendREVIEW | +$1,400 | |
| Good rating (4.3★)METRIC | +$800 | |
| Localized (7 languages)METRIC | +$600 | |
| Pre-traction phase (24 ratings)METRIC | −$300 |
METRIC = structural app data · REVIEW = mined from user reviews · ✓ VERIFIED = Stripe-verified anchor (TrustMRR)
📈 Reviews Growth
LIVECumulative review count from first BU snapshot. Each point = a tracked update.
⭐ Rating Trend
LIVEAverage rating evolution. Updates with each new review batch.
App Specs
🔐 Own this app? Claim & verify MRR →💾 30 MB🔞 4+📱 iOS 12.0+🔖 v5.28🔄 updated 2y ago🌐 NL, EN, FR, DE, IT +2📂 Business💰 Paid🚀 Launched 2011 (15y old)
📝 About this app
One of the most powerful calendars on iOS. Advanced views with plenty of options all designed for speed and flexibility.
You wont get this much information at a glance from any other calendar, and adding events in-line allows you to get in and out and on with your busy day.
Based on Extreme Agenda, it gives you the powerful calendar based views you want at a low price, and allows you to purchase the other features of the full Organizer once you need them.
Features Include:
Great Calendaring
• Powerful views including Year, Month, Week, Upcoming Agenda List, and Day.… View full description on the official store →
You wont get this much information at a glance from any other calendar, and adding events in-line allows you to get in and out and on with your busy day.
Based on Extreme Agenda, it gives you the powerful calendar based views you want at a low price, and allows you to purchase the other features of the full Organizer once you need them.
Features Include:
Great Calendaring
• Powerful views including Year, Month, Week, Upcoming Agenda List, and Day.… View full description on the official store →
🆕 What's New · v5.28
Settings screen updates for iOS 17.
Please help support Birdsoft by checking out our new Ulti-Planner calendar app and maybe giving it a review if you like it. It is the next generation of our calendar apps and has a lot of new features we don't have here yet.… Full release notes →
Please help support Birdsoft by checking out our new Ulti-Planner calendar app and maybe giving it a review if you like it. It is the next generation of our calendar apps and has a lot of new features we don't have here yet.… Full release notes →
Profile & Insights
Everything we know — and don't — about this app and its company.
Identification
- App name
- Extreme Kalender
- Developer
- Birdsoft LLC
- Bundle ID
- biz.birdsoft.xcal
- App Store URL
- Open in App Store
- Category
- Business
- Content rating
- 4+
- Languages
- NL, EN, FR, DE, IT, PT, ES
Company
- Website
- Not found
- Tagline
- Today
- Description
- Find apps and games for iPhone, iPad, Mac, and more on the App Store.
- Founded
- Not found
- HQ / Address
- Not found
- Employees
- Not found
- Logo
- OG image
Revenue
- Verified revenue / mo
- Not found
- AI revenue estimate / mo
- Not found
- AI annual estimate
- Not found
- ML model estimate / mo
- $16.8K/mo
- Top-grossing rank
- Outside top 100 in US Business
- All-time revenue
- Not found
- Pricing
- Not found
Founder
- Name
- Not found
- X / Twitter
- Not found
- Not found
- GitHub
- Not found
- X followers
- Not found
- Public statements
- Not found
Funding
- Total raised
- Not found
- Last round
- Not found
- Investors
- Not found
- Crunchbase
- Not found
- AngelList
- Not found
Press & Links
- Articles found
- Not found
- Listed on
- Not found
- Blog
- Not found
- Press / News
- Not found
Contacts & Socials
- Socials
- Not found
- Not found
- Phone
- Not found
- Contact page
- Not found
- About page
- https://apps.apple.com/us/iphone/story/id1701453284
⭐Recent App Store Reviews49 latest · avg 4.08★ · 46.9% 5★ · 6.1% 1★
5★23 (47%)
4★15 (31%)
3★6 (12%)
2★2 (4%)
1★3 (6%)
+0 ratings/week
Praise: great ×13 love ×9 best ×8 awesome ×6 recommend ×3Complaints: refund ×1 crash ×1
Top positive
★★★★★ Great
I am new to the app world but wanted a calendar so read the reviews and tried this one. I agree, this is a very easy colander to use. I would love to see bigger icons.…
★★★★★ Best ever
My mother has Alzheimer's and this app has been a life saver for helping me keep up with dr appointments…
Top negative
★☆☆☆☆ Doesn't work for me
Save your money, I found one for a third of the price that works a lot better. I can not get this one to sink between my two IPhones and my IPad. The tiny calendar automatically sinked the three together and was only $2.99. I could not g…
★☆☆☆☆ Don't buy it
Horrible . Erased my entire month just a few minutes after putting it all in. It also is not used friendly. Even my very skilled computer friend was annoyed with it while trying to use it. Don't waste your money like I did.…
📈Ratings growth24 ratings+14% lifetimeShow 3-year history estimate ▾
Tracked (60 weeks) Pre-tracking estimate (37 weeks) · model-based, ±5% noise · anchored to release date and current value
🌍Geographic ReachNot ranked
This app is currently outside the top 100 grossing in all 9 countries we monitor (US, UK, DE, FR, JP, CA, AU, BR, IN). Niche or new apps often launch this way — popularity rankings appear once daily revenue clears the regional threshold.
Profile is built from iTunes Lookup + developer site scrape + ML revenue model. Empty fields show "Not found" — additional sources (Crunchbase, X, IndieHackers, Acquire.com) coming.
More by Birdsoft LLC
View all →
Full revenue analysis
Read the article-style breakdown for Extreme Kalender: category rank, percentile, growth signal, comparable apps, and how the forecast is calibrated against verified-MRR anchors in this niche.