Stratum vs Flow: Real App Blocking Shouldn't Be a Paid Unlock
A practical comparison for students deciding between Stratum and Flow for study sessions, distraction control, and deadline tracking.
Flow is a genuinely well-built, minimalist Pomodoro timer with a loyal following, particularly among Mac users who like its menu-bar presence and calendar logging. It's not aimed specifically at students — it markets itself just as much to coders and remote workers — but it does show up regularly in "best focus app" roundups, which makes it worth comparing directly.
This page isn't saying Flow is a bad app. It's for students comparing tools and deciding whether Stratum is the better fit for actually getting through exam season.
Quick comparison
| Stratum | Flow | |
|---|---|---|
| App blocking on iPhone | Included free — iOS Screen Time locks distracting apps during a session | Free tier only blocks apps/websites on Mac; iPhone blocking requires a paid one-time unlock |
| Deadline tracking | Dual-view calendar showing exactly how far away exams and assignments are | Calendar sync logs completed sessions after the fact — it doesn't count down to exams or assignments |
| Study analytics | Streaks, hours studied, subject breakdown, weekly summary | Session statistics and iCloud sync; no subject-level academic breakdown |
| Self-control mechanism | Apps are physically locked out during the session | "Commitment mode" prevents pausing/skipping the timer itself — it doesn't block other apps |
| Built for | Students specifically | General productivity — students, developers, remote workers |
| Platform | iOS (Android in progress) | iOS, Mac |
Where Flow genuinely wins
Flow is polished. It has home and lock screen widgets, Dynamic Island support, Apple Health sync, and a genuinely loyal base of Mac users who value its minimalist design and menu-bar timer. If your main study environment is a Mac and you want a lightweight Pomodoro tool with a clean UI, it's a reasonable pick.
Where Flow falls short for actual studying
Here's the catch that matters most for phone-based studying: Flow's app-and-web blocking on iPhone is not part of the free experience. By the developer's own feature list and user reports, the free tier's blocking only functions on Mac — to get any blocking on the device students are actually distracted on, you need to purchase the one-time Pro unlock. For an app whose entire pitch to distraction-prone users is "we block apps and websites," gating that specific feature behind a paywall on iOS undercuts the exact reason a student would download it.
Flow also has a "commitment mode" that prevents you from pausing or resetting the timer — but that's a different kind of restriction. It stops you from quitting the session early; it does nothing to stop you from picking up your phone and opening Instagram while the timer keeps running, unless you've already paid for the separate blocking feature.
On deadlines, Flow's calendar sync is retrospective — it logs a completed session into Apple or Google Calendar so you can look back at your day. It has no forward-looking view of upcoming exams or assignments, and no subject-level breakdown of where your hours actually went.
Why Stratum wins for students
Stratum includes real, system-level app blocking through iOS Screen Time for free — there's no separate paid unlock required to get the one feature that actually keeps a distracted student off their phone. Layer on a dual-view calendar built specifically to count down to exams and assignments, plus a stats screen with subject-by-subject breakdowns, streaks, and weekly summaries, and Stratum is aimed squarely at the academic use case Flow was never designed around.
Verdict
If you're a Mac-based professional who wants a clean, general-purpose Pomodoro timer and doesn't mind paying extra for iPhone blocking, Flow is solid. If you're a student who needs your phone locked down during study sessions without paying for the privilege, and you want your timer connected to your actual exam calendar, Stratum is the more direct fit.