Comparison

Jam Timer vs Jamzo

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

Head to head
About

Jam Timer

This app provides precise timing control for roller derby officials, offering built-in configurations for various leagues and professional timing features. It's designed for one-handed operation with a clear display and haptic feedback, working completely offline.

Highlights
  • Built-in game configurations
  • Professional timing control
  • Designed for officials
  • Game management features
  • Offline operation
Features
Currently charting
Read full description

RollTimer: The Professional Jam Timer for Roller Derby Officials Designed specifically for the jam-timer position, RollTimer eliminates the need for traditional stopwatches and provides precise timing control for all roller derby formats. Whether you're officiating WFTDA sanctioned bouts, RDCL tournaments, or OSDA games, RollTimer has the configuration you need. Key Features: Built-in Game Configurations WFTDA standard timing rules RDCL tournament settings OSDA game format Custom configurations for scrimmages and special events Professional Timing Control Precise jam timing with lead jammer call-off Period clock management Lineup time tracking Team and official timeout timers Automatic vibration warnings at configurable intervals Designed for Officials Large buttons for one-handed operation Clear, high-contrast display visible from across the track Haptic feedback for critical timing events Works completely offline - no internet required Game Management Track team scores and timeouts Monitor official reviews remaining Complete game history and statistics Export game data for league records Perfect for: NSO jam timers at sanctioned bouts Tournament directors managing multiple games League officials during practice scrimmages Coaches timing drills and scenarios Referees needing backup timing Why Choose RollTimer: Unlike generic stopwatch apps, RollTimer understands roller derby. Every feature is built around the specific needs of derby timing, from the 30-second lineup to the 2-minute jam clock. The large, accessible interface ensures you can focus on the game, not fumbling with tiny buttons. Trusted by officials across leagues worldwide, RollTimer brings professional-grade timing to your mobile device. Download now and experience the difference purpose-built software makes. Offline Operation: RollTimer works completely offline with no network requirements, perfect for venues with poor connectivity. All game data is stored locally on your device for maximum reliability.

About

Jamzo

Features
Read full description

Jamzo brings together essential tools to support teams and officials during roller derby games. NEW — LINEUP & PENALTY TRACKER Easily track lineups and penalties throughout the game: • Record the skaters participating in each jam • Identify jammers, pivots, and blockers • Assign penalties and track Penalty Box visits • View the game history in real time • Work independently or with another operator on separate devices • Access a complete game recap • Export game data for review or archiving SCOREKEEPER • Record the score jam by jam • Follow the game’s progress in real time • Choose between solo and dual modes • View and export the game recap TIMING TOOLS • Jam Timer: track jams, intervals, and periods • Penalty Timer: time Penalty Box visits • Blocker Timer: manage blocker penalties • Jammer Timer: manage jammer penalties • Dual Timer: use two timers on a single screen TEAM DIRECTORY • Discover roller derby teams • View their city and country • Access their social media pages RULES QUIZ • Test your roller derby knowledge • Choose your difficulty level • Learn and review the rules in a fun way Jamzo features a clear, responsive interface designed to remain easy to use in real game conditions.

Screenshots

Jam Timer4 screens
Jamzo4 screens

Verdict

The call

The clearest difference is price: Jamzo at Free against Jam Timer's $3.99. Jam Timer's advantage is chart position (#188 vs unranked). On ads, in-app purchases, device support and iOS requirement 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

Jamzo is free to download; Jam Timer costs $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Scorecard2 real differences · 8 level
Jam Timer versus Jamzo: the parameters behind the verdict, then further details
ParameterJam TimerJamzo
Price$3.99Free — better
Rating1.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequency—Every 6 weeks
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
Best chart rank#188 — better—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.615.1 — better
Further details — not scored
Size19 MB44 MB
Age rating4+17+
DeveloperDLYCharles Robart

In-app purchases

None

Jam Timer

No in-app purchases

None

Jamzo

No in-app purchases

Questions

Is Jam Timer free?
Jam Timer costs $3.99, with no in-app purchases.
Is Jamzo free?
Jamzo is free to download, with no in-app purchases.
Do Jam Timer or Jamzo have ads?
Neither Jam Timer nor Jamzo shows ads.

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