Comparison

MillisecondTimer vs Reaction Time Test

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

MillisecondTimer

This app provides highly accurate timing tools, including a countdown timer, stopwatch, and clock, all with millisecond precision. It's designed for precise measurements in workouts, games, and everyday situations, offering background operation and seamless switching between apps.

Highlights
  • Millisecond precision timing
  • Countdown timer with custom intervals
  • Stopwatch for accurate interval recording
  • Real-time millisecond clock display
  • Background operation and notifications
  • Recent timers for quick reuse
  • Customizable 12/24 hour clock format
Features
Read full description

Millisecond Timer is an all‑in‑one app that lets you use a countdown timer, stopwatch, and clock with millisecond (0.001 second) precision. Millisecond Stopwatch records your time accurately down to the millisecond, and Millisecond Clock shows the current time with millisecond precision. When you first install the app, a simple tutorial appears automatically so you can learn how it works and start using it right away. Use Millisecond Timer and Millisecond Stopwatch in situations like these - Measuring workout intervals and exercise times that need accurate records (running, marathon training, etc.) - Everyday situations where you need a precise countdown - Events or games that require millisecond‑level countdowns - Timer challenge games with friends, such as “Who can stop closest to 2.785 seconds?” or for fair draws and random picks 【Millisecond Timer】 - Set timers in hours, minutes, seconds, and milliseconds. - Easily increase or decrease the time using the + and − buttons. - Press and hold the + or − button to quickly set the exact time you want. - Instantly reuse your recent timers from the Recent Timers list. - Tap the displayed time to type in a value faster than using buttons. - Get notified when the timer finishes, even if you’re using another app (background) or your device is locked. - If the timer is running and you switch to another app, it will keep counting and resume seamlessly when you return. 【Millisecond Stopwatch】 - Record times one by one with millisecond precision. 【Millisecond Clock】 - See the current time in real time, down to the millisecond. - Choose between 12‑hour and 24‑hour formats in Settings. - Enjoy a clean digital clock design with a digital‑style font. If you find a bug or have a feature request, go to Settings in the app and use “Send Bug Report & feedback” to contact the developer. 【Pro Version】 Pro is available as a monthly or yearly subscription, as well as a lifetime purchase. - Subscriptions are charged to your Apple ID. - You can manage or cancel your subscription at any time in your Apple Account settings. - If you do not cancel at least 24 hours before the next billing date, your subscription may renew automatically. - All subscription terms follow Apple’s App Store policies. • Terms of Use: https://comdori.tistory.com/179 • Privacy Policy: https://comdori.tistory.com/161

About

Reaction Time Test

Features
Read full description

How fast are you, actually? Reaction Time measures the gap between seeing something change and moving your finger — and it measures it correctly. Most reaction apps stop the clock when your finger lifts off the glass. That adds your own release time to every single result, which is why their numbers run slow. This one stops the moment your finger lands. FOUR WAYS TO MEASURE • Simple — the screen turns green, you tap. Raw reaction, nothing else. • Choice — one of four panels lights up. Tap that one. • Go / No-Go — green means tap, red means hold still. Speed plus restraint. • Timing — a bar sweeps toward a line. Tap exactly when it arrives. STATISTICS, NOT JUST A HIGH SCORE Five valid attempts per session. You get the median (the number worth trusting), your best, your mean, and your spread — how consistent you were. Attempts under 100 ms are marked as false starts and attempts over 3 seconds as misses. Both are shown to you and both are left out of the maths, with the reason on screen. WHAT IT DOES NOT DO • No account. Nothing to sign up for. • No paywall and no subscription. Every test is free. • No data collected. Your sessions never leave this iPhone. • Works completely offline, including in airplane mode. Tiers are our own scale, not a population percentile. This app is for measurement and entertainment, not medical or cognitive assessment.

Screenshots

MillisecondTimer4 screens
Reaction Time Test3 screens

Verdict

The call

The clearest difference is in-app purchases: Reaction Time Test at none against MillisecondTimer's 3. Reaction Time Test also leads on ads (none vs shown) and update cadence (every 8 days vs every 3 weeks). MillisecondTimer's advantage is iOS requirement (15.6 vs 17.0). On price and device support 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. MillisecondTimer sells 3 in-app purchases, starting at $1.00 per month. Reaction Time Test asks for nothing beyond the download.

UpkeepUpdate frequency

MillisecondTimer ships an update every 3 weeks, Reaction Time Test every 8 days. The most recent releases landed on November 3, 2026 and November 6, 2026 respectively.

Scorecard4 real differences · 5 level
MillisecondTimer versus Reaction Time Test: the parameters behind the verdict, then further details
ParameterMillisecondTimerReaction Time Test
PriceFreeFree
Rating5.0 (10 ratings) — better—
Number of ratings10 — better—
Update frequencyEvery 3 weeksEvery 8 days — better
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPodiPhone, iPad
Requires iOS15.6 — better17.0
Further details — not scored
Size30 MB5 MB
Age rating4+4+
DeveloperWONJI HAJinwan Kim

In-app purchases

3 purchases

MillisecondTimer

Subscriptions2
  • MillisecondTimer Pro Month Plan$1.001 Month
  • MillisecondTimer Pro Annual Plan$5.991 Year
One-time1
  • MillisecondTimer Pro Lifetime$34.99
None

Reaction Time Test

No in-app purchases

Questions

Is MillisecondTimer free?
MillisecondTimer is free to download, with in-app purchases available.
Is Reaction Time Test free?
Reaction Time Test is free to download, with no in-app purchases.
Do MillisecondTimer or Reaction Time Test have ads?
MillisecondTimer shows ads; Reaction Time Test does not.
Which is updated more often, MillisecondTimer or Reaction Time Test?
MillisecondTimer ships an update every 3 weeks, and Reaction Time Test every 8 days. Most recently, MillisecondTimer was updated on November 3, 2026 and Reaction Time Test on November 6, 2026.

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