Extreme Kalender
60
Quality Score
Solid
Extreme Kalender
Low confidence
✍️ 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.
Quality Score is 60: Solid (established niche player). For a Business app, that means established niche player. The full BU Investment Matrix below scores 8 dimensions including monetisation, growth, and operational risk.
Track changes month-over-month in the Performance section below: live snapshot history and revenue forecast included.
💰 Monthly revenue · now vs forecast
● Right now
$5.0K
per month
→
12-mo forecast
$5.2K – $10.8K
per month
→
24-mo forecast
$6.4K – $19.2K
per month
MID tier
💡 Grow this revenue
Free AI audit of this app’s store listing
- Title & subtitle keyword fit
- Description hook & conversion structure
- Screenshots, ratings, reviews strategy
Typical impact: +2-5× organic installs
📊 Performance Tracking LIVE
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Rating
—
Reviews
—
Forecast Revenue / mo
—
Snapshots tracked
0
since first record
ONE-TIME · BUILD
💰 Estimated build cost
$75K
↳ What it cost to build · not monthly revenue
Likely range $55K – $100K
$25K · MVP floor
$100K · indie scale
$500K+ · studio build
📈
Pays back in ~4 months at current MRR
Synthetic estimate. Inputs: category complexity, file size, screen count, monetization layer, platform reach, age × team-size proxy. Calibrated against 2024-2026 indie-agency rate surveys. Full math + source list on /methodology.
Where the money goes
| 🧱 MVP baseline (design + 1-store ship) | +$28K |
| 📱 5 unique screens × $4.5K | +$22K |
| ⚙ Business complexity ×1.50 | +$25K |
Total estimate
$75K
ONE-TIME · EXIT VALUE
💵 Estimated acquisition value
$250K
↳ What it would sell for · not monthly revenue
Marketplace range $200K – $325K · 15× MRR multiple
💸
~3.3× return on build cost
Synthetic estimate. Multiple band derived from ad-supported + age, rating quality, category demand, and user-base maturity. Calibrated against 2024-2026 indie-app-marketplace closed-deal medians. Full math + comparable deal list on /methodology.
How the multiple was built
| 📺 Ad-supported base | 15× MRR |
| 🏷 Business category multiple | +10% |
| ⭐ Small user base (<1K ratings) | -8% |
Final multiple
15× MRR
🔬
How we forecast this revenue
MEDIUM CONFIDENCEBaseline
$5.0K/mo · ML-estimated from 234 triggers
Growth rate
+4.0% MoM · MID tier baseline (compound monthly)
Direction
Headwinds: rating drift may slow acquisition
6 months
$4.7K – $7.9K
12 months
$5.2K – $10.8K
24 months
$6.4K – $19.2K
Compound growth at +4.0% MoM (tier baseline for MID). Range widens with horizon — typical noise band ±25% at 6mo.. Ranges widen with horizon — distant futures carry more uncertainty.
📊
BU Investment Matrix
Below median · 43/100MID TIERunderperforming peersGrowth Velocity
5.0
Founder Strength
6.2
Product Quality
3.5
Revenue Strength
3.7
Monetization Maturity
1.0
Defensibility
6.0
Market Position
2.0
Operational Safety
7.0
- 💰 Revenue: Modest — $3K - $7K/mo · MID tier · medium confidence, trajectory unclear.
- ⭐ Quality: 4.33★ across 24 reviews — weak — significant quality concerns.
- 📍 Market: Not yet charting in any of the 9 monitored markets.
- 📈 Growth: ⚠ last update 857d ago — possibly dormant.
- ⚠️ Risk: Moderate — dormant (857d since update).
🎯 For competitors: Mixed picture. Worth competing if you have a clear UX or pricing edge — otherwise crowded segment.
💵 For acquirers: Estimated asking range 18-32× monthly = $90K-$160K. Portfolio play ($29K/mo combined) commands premium.
Composite of 8 dimensions computed deterministically from public signals — no LLM, every score traces back to a measurable input. Default weights shown; "compete" / "acquire" / "invest" lenses re-weight without re-fetching.
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.
🆕 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
- Available
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
Founder data not yet collected for this app.
Funding
Funding data not yet collected for this app.
Press & Links
Press & Links data not yet collected for this app.
Contacts & Socials
Contacts & Socials data not yet collected for this app.
📈Ratings growth24 ratings+9% 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.
💰Pricing History$0.00 → $7.99 (+0%)
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.
📝 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 →
App Specs
🔐 Own this app? Claim & verify MRR →💾 30 MB🔞 4+📱 iOS 12.0+🔖 v5.28🔄 updated 0d ago🌐 NL, EN, FR, DE, IT +2📂 Business💰 Paid
📅
What Worked™ · Development Pipeline
9 EVENTS TRACKEDDetected changes in this app over its tracked lifetime — each event links cause (what changed) to effect (what moved). Sorted newest first.See full history →Version history →
2026-05
⭐
Rating ↑ 3.80 → 4.33 (improved 0.53★)
2026-05
💲
Went paid — introduced $7.99 price point
2012-09
📈
Crossed 50 ratings — social-proof flywheel kicking in
2011-08
⭐
Rating ↑ 1.67 → 2.00 (improved 0.33★)
2011-08
📈
Crossed 10 ratings — social-proof flywheel kicking in
2011-06
⭐
Rating ↓ 2.33 → 2.00 (dropped 0.33★)
2011-05
⭐
Rating ↑ 2.00 → 2.33 (improved 0.33★)
2011-05
🚀
First tracked snapshot — initial data captured
2011-05
⭐
Rating ↑ 1.00 → 2.00 (improved 1.00★)
🌍
Multi-Country Performance
Available in 9 of 9 monitored markets| Market | Rating | Reviews | Current version |
|---|---|---|---|
| 🇦🇺 AU | 4.33333★ | 3 | 4.33333★ this version |
| 🇧🇷 BR | 5★ | 1 | 5★ this version |
| 🇨🇦 CA | 4.42856★ | 7 | 4.42856★ this version |
| 🇩🇪 DE | 3.83333★ | 6 | 3.83333★ this version |
| 🇫🇷 FR | 3★ | 2 | 3★ this version |
| 🇬🇧 GB | 3.75★ | 8 | 3.75★ this version |
| 🇮🇳 IN | 0★ | 0 | — |
| 🇯🇵 JP | 2★ | 1 | 2★ this version |
| 🇺🇸 US | 4.33333★ | 24 | 4.33333★ this version |
🔔
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📝 Description
95
BU Score · Transcendent
More by Birdsoft LLC
View all →📦 Portfolio summaryINDIE studio
3apps·$29K/mocombined
Lead-app heavy — top app contributes 57%
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About this analysis
Why low confidence: only 24 ratings · no founder-verified revenue (model estimate only) · revenue figure is directional only.
📌 Final verdict — read this before you trust the numbers above
Extreme Kalender is a small / niche iOS app in the business space with weak public traction — only 24 ratings, no founder-verified MRR, and not ranked in any monitored grossing chart. The app appears to be monetised, but public signals are too sparse for a precise revenue estimate.
Bottom line: treat all revenue, audience and acquisition-value numbers on this page as directional only — not founder-verified facts.
❓ Frequently Asked Questions
4 answers · auto-generated from this app's public dataHow much does Extreme Kalender make per month?▴
Our model estimates Extreme Kalender earns roughly $16K/mo, but with only 24 ratings the confidence interval is wide. No founder-verified MRR is available for this app, so this is a model output calibrated against comparable apps in the same category. See methodology for the formula.
What apps are like Extreme Kalender?▴
Browse the full Business category catalog to find similar apps with revenue, build cost, audience and tech stack data. Each /p/{slug} page also shows a Compare side-by-side widget with three peer apps from the same niche.
Who makes Extreme Kalender?▴
Extreme Kalender is published by Birdsoft LLC on the Apple App Store. See the full publisher portfolio (other apps by the same developer) via the More by developer block on the product page above.
What is Extreme Kalender's BU Score?▴
Extreme Kalender has a BU Score of 60/100 (Solid). The score combines App Store rating, ratings count, monetization model and revenue signals calibrated against founder-verified MRR anchors. See the BU Score formula.