Proton Calendar
60
Quality Score
Solid
Proton Calendar
Medium confidence
✍️ bumetric analysis
“
Proton Calendar is an iOS app from Proton AG in the Productivity category, currently rated 3.9★ across 1,193 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 Productivity 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
Loading…
Rating
—
Reviews
—
Forecast Revenue / mo
—
Snapshots tracked
0
since first record
ONE-TIME · BUILD
💰 Estimated build cost
$100K
↳ What it cost to build · not monthly revenue
Likely range $75K – $135K
$25K · MVP floor
$100K · indie scale
$500K+ · studio build
📈
Slow ROI — current MRR is well below build cost
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 |
| 📦 Asset bundle (182 MB) | +$40K |
| ⚙ Productivity complexity ×1.10 | +$9K |
Total estimate
$100K
ONE-TIME · EXIT VALUE
💵 Estimated acquisition value
$20K
↳ What it would sell for · not monthly revenue
Marketplace range $15K – $25K · 15× MRR multiple
💸
~0.2× build cost (under-water)
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 |
| ⭐ ★ rating 3.5-4.0 (mixed) | -8% |
| 🏷 Productivity category multiple | +8% |
Final multiple
15× MRR
👥 Estimated audience size
89K
Lifetime downloads (US-equivalent)
Monthly active
26K
Daily active
11K
Synthetic estimate from ratings × category benchmarks. Calibrated against 2024-2026 mobile-attribution retention + DAU/MAU reports. Numbers are US-storefront-equivalent — true global audience can be 5-10× larger for international apps. Full math + source list on /methodology.
How we sized it
| 📲 Productivity engagement | ~75 installs / rating |
| 🔁 Productivity D30 retention | 30% |
| 📍 DAU / MAU stickiness | 0.45 |
DAU / MAU
43% sticky
🔬
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)
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 · 53/100MID TIERunderperforming peersGrowth Velocity
5.0
Founder Strength
7.6
Product Quality
7.1
Revenue Strength
3.7
Monetization Maturity
1.0
Defensibility
5.9
Market Position
2.0
Operational Safety
10.0
- 💰 Revenue: Modest — $3K - $7K/mo · MID tier · medium confidence, trajectory unclear.
- ⭐ Quality: 3.94★ across 1,193 reviews — solid.
- 📍 Market: Not yet charting in any of the 9 monitored markets.
- 📈 Growth: Insufficient signal to assess trajectory.
- ⚠️ Risk: Low — no material risk signals detected.
🎯 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 ($123K/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 8 of 8 triggers
Our ML model uses 200+ signals from public data. These are the most influential for this app:
| bugsREVIEW | −$1,800 | |
| 5 starREVIEW | +$1,800 | |
| Low install base (1,193 ratings)METRIC | +$1,500 | |
| Multilingual (26 languages)METRIC | +$1,500 | |
| highly recommendREVIEW | +$1,400 | |
| slowREVIEW | −$1,200 | |
| Established app (3y old)METRIC | +$800 | |
| Ad-supported / freemiumMETRIC | +$600 |
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 · v2.25.0
Minor fixes and improvements.
Profile & Insights
Everything we know — and don't — about this app and its company.
Identification
- App name
- Proton Calendar
- Developer
- Proton AG
- Bundle ID
- ch.protonmail.calendar
- App Store URL
- Open in App Store
- Category
- Productivity
- Content rating
- 4+
- Languages
- BE, CA, CS, DA, NL, EN, FI, FR, KA, DE, EL, HU, ID, IT, KO, NB, PL, PT, RO, RU, SK, ES, SV, ZH, TR, UK
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
- $1.2K/mo
- Top-grossing rank
- Outside top 100 in US Productivity
- 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 growth1,193 ratings+191% lifetimeShow 3-year history estimate ▾
Tracked (56 weeks) Pre-tracking estimate (34 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.
📝 About this app
A calendar is a record of your life: Proton Calendar helps keep it private.
Make the most of your time
- See your upcoming events as you like with agenda or day view
- View and reply to invites
- Events and invites are automatically added to your calendar from your Proton Mail inbox
- View your schedule in light or dark mode
- Add multiple reminders for your events
- Create recurring events on a daily, weekly, monthly, yearly, or custom basis
- Keep your calendar in sync across all your devices
Private by default
- No ads, no trackers, and no data harvesting… View full description on the official store →
Make the most of your time
- See your upcoming events as you like with agenda or day view
- View and reply to invites
- Events and invites are automatically added to your calendar from your Proton Mail inbox
- View your schedule in light or dark mode
- Add multiple reminders for your events
- Create recurring events on a daily, weekly, monthly, yearly, or custom basis
- Keep your calendar in sync across all your devices
Private by default
- No ads, no trackers, and no data harvesting… View full description on the official store →
App Specs
🔐 Own this app? Claim & verify MRR →💾 182 MB🔞 4+📱 iOS 16.0+🔖 v2.25.0🔄 updated 0d ago🌐 BE, CA, CS, DA, NL +21📂 Productivity💰 Paid
📅
What Worked™ · Development Pipeline
11 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 ↑ 2.88 → 3.94 (improved 1.06★)
2026-05
📈
Crossed 500 ratings — social-proof flywheel kicking in
2026-03
⭐
Rating ↓ 3.50 → 2.89 (dropped 0.61★)
2026-03
⭐
Rating ↑ 2.88 → 3.50 (improved 0.62★)
2026-03
📈
Crossed 500 ratings — social-proof flywheel kicking in
2023-05
📈
Crossed 100 ratings — social-proof flywheel kicking in
2023-01
📈
Crossed 50 ratings — social-proof flywheel kicking in
2022-12
📈
Crossed 10 ratings — social-proof flywheel kicking in
2022-12
⭐
Rating ↓ 4.20 → 3.83 (dropped 0.37★)
2022-12
⭐
Rating ↓ 5.00 → 4.00 (dropped 1.00★)
2022-11
🚀
First tracked snapshot — initial data captured
🌍
Multi-Country Performance
Available in 9 of 9 monitored markets| Market | Rating | Reviews | Current version |
|---|---|---|---|
| 🇦🇺 AU | 3.84906★ | 106 | 3.84906★ this version |
| 🇧🇷 BR | 4.07143★ | 28 | 4.07143★ this version |
| 🇨🇦 CA | 4.10769★ | 195 | 4.10769★ this version |
| 🇩🇪 DE | 3.59831★ | 356 | 3.59831★ this version |
| 🇫🇷 FR | 3.8855★ | 262 | 3.8855★ this version |
| 🇬🇧 GB | 3.58416★ | 202 | 3.58416★ this version |
| 🇮🇳 IN | 4.15789★ | 19 | 4.15789★ this version |
| 🇯🇵 JP | 3.72973★ | 37 | 3.72973★ this version |
| 🇺🇸 US | 3.96656★ | 1,256 | 3.96656★ this version |
🔔
Track this app’s revenue
FREEGet an email when revenue moves by your threshold. No spam, unsubscribe in one click.
📝 Description
95
BU Score · Transcendent
Full revenue analysis
Read the article-style breakdown for Proton Calendar: category rank, percentile, growth signal, comparable apps, and how the forecast is calibrated against verified-MRR anchors in this niche.
More by Proton AG
View all →📦 Portfolio summaryMID studio
9apps·$123K/mocombined
Lead-app heavy — top app contributes 60%
Similar apps in Productivity
About this analysis
Why medium confidence: 1,193 ratings · no founder-verified revenue (model estimate only).
❓ Frequently Asked Questions
4 answers · auto-generated from this app's public dataHow much does Proton Calendar make per month?▴
Based on our ML-calibrated revenue forecast, Proton Calendar earns approximately $1.2K/mo. This is a US-storefront-equivalent estimate; global revenue can be several times larger for internationally-distributed apps. See the methodology page for the full formula and confidence bands.
What apps are like Proton Calendar?▴
Browse the full Productivity 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 Proton Calendar?▴
Proton Calendar is published by Proton AG 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 Proton Calendar's BU Score?▴
Proton Calendar 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.