Free Alternative to iStat Menus

Stats is the clear winner for free system monitoring. Developed by Serhiy Mytrovtsiy and completely open-source, it shows CPU, GPU, memory, disk, network, battery, fans, and sensors right in your menu bar—exactly what iStat Menus does. The app is actively maintained with over 17,000 stars on GitHub, works great on Apple Silicon including M3 and M4 chips, and is completely free with no limitations.

You can install it with Homebrew and customize every aspect of how your stats are displayed. The project is written in Swift using modern macOS APIs, ensuring native performance and tight integration with the operating system. Stats receives monthly updates with bug fixes and new features based on community feedback.

The modular architecture allows you to enable only the monitoring widgets you need, reducing both menu bar clutter and system resource usage. Unlike commercial alternatives that bundle everything together, Stats gives you granular control over every metric displayed. The application supports light and dark mode seamlessly, with customizable color schemes that integrate beautifully with macOS Ventura and Sonoma's design language.

eul takes a more minimal approach—it shows system stats in a clean, unobtrusive way. Written 100% in Swift using SwiftUI, it requires macOS 10.15 Catalina or later and works natively on Apple Silicon. The design is modern and fits well with macOS aesthetics, using native system fonts and colors that adapt to light and dark modes automatically.

Note that the Mac App Store version is outdated; install via Homebrew instead to get the latest features and bug fixes. The app's minimalist philosophy means you get essential monitoring without overwhelming configuration options—perfect for users who want a set-it-and-forget-it solution. eul's resource footprint is incredibly small, typically consuming less than 15MB of RAM and under 1% CPU usage during normal operation. The SwiftUI-based interface ensures smooth animations and responsive interactions, even on older Macs. eul follows Apple's Human Interface Guidelines closely, making it feel like a native macOS component rather than third-party software. For users who appreciate Apple's design philosophy of simplicity and elegance, eul delivers system monitoring that doesn't compromise aesthetic integrity.

MenuMeters is a classic Mac utility that's been around since the PowerPC days. It adds simple CPU, memory, disk, and network monitors to your menu bar as true SystemUIServer plugins (Menu Extras). Icons can be reordered with Command-drag and remember their positions across logins.

Released under the GNU GPL v2, it's completely free and open source. The project has been maintained by multiple developers over the years, with the current fork by emcrisostomo ensuring compatibility with modern macOS versions. MenuMeters is ideal for users who want reliable, no-frills monitoring that just works without fancy graphics or animations.

The plugin architecture means MenuMeters integrates at the system level, providing stability and compatibility that standalone apps sometimes lack. For longtime Mac users who remember MenuMeters from the OS X 10.6 Snow Leopard days, the modern version preserves that familiar interface while adding support for Retina displays and modern macOS features. MenuMeters represents the Unix philosophy applied to Mac monitoring: do one thing well, keep it simple, and stay out of the way.

Activity Monitor comes with every Mac—no installation needed. While it's not a menu bar app by default, you can add a dock icon that shows CPU usage. For detailed investigation of what's using resources, it's actually more powerful than iStat Menus since you can inspect and quit individual processes, view thread counts, port information, and open files.

Perfect for troubleshooting without installing anything. Activity Monitor is Apple's official diagnostic tool, receiving updates with every macOS release. The Energy tab is particularly useful for MacBook users trying to maximize battery life by identifying power-hungry apps.

Activity Monitor provides system-level access that third-party apps can't match, including kernel task inspection, system diagnostics, and low-level process details. For developers debugging memory leaks, tracking down runaway processes, or analyzing application behavior, Activity Monitor's Sample Process feature provides stack traces and detailed execution profiles that are invaluable for troubleshooting. While it lacks the convenience of menu bar integration, Activity Monitor compensates with depth and authority—it's the tool Apple engineers use to diagnose macOS issues.

MonitorControl doesn't monitor system resources, but it's an essential free utility for Mac users with external displays. It adds menu bar controls for adjusting external monitor brightness and volume using DDC (Display Data Channel) protocol. This means you can use keyboard shortcuts or menu bar sliders to control your Dell, LG, or Samsung monitor just like you would your MacBook's built-in display.

No more fumbling with monitor buttons—adjust brightness with the same F1/F2 keys you use on your MacBook. MonitorControl supports multiple monitors simultaneously and works with most modern displays that support DDC/CI protocol. The app is open-source, lightweight, and integrates seamlessly with macOS, including Stage Manager and multiple desktop spaces.

For users who frequently adjust monitor settings throughout the day based on ambient lighting or work tasks, MonitorControl is an indispensable productivity enhancer. The ability to create custom keyboard shortcuts for different brightness presets makes it easy to switch between day and night configurations instantly.

Hot is a minimalist menu bar app that does one thing exceptionally well: shows your Mac's CPU temperature. That's it. No graphs, no configuration menus, no feature bloat—just a simple number that turns red when your Mac gets too hot.

Perfect for MacBook users who want to monitor thermal throttling without the complexity of full-featured system monitors. Hot is open-source, written in Swift, and consumes minimal resources (under 5MB RAM, negligible CPU usage). The app is particularly useful for identifying cooling issues, monitoring performance during intensive tasks like video rendering, or ensuring proper ventilation when running your MacBook in clamshell mode.

Hot's simplicity is its strength—launch it once and forget about it until you need to check if your Mac is overheating. The color-coded display provides instant visual feedback: blue for cool, white for normal, orange for warm, and red for hot. For users who value simplicity and focus, Hot delivers essential thermal monitoring without unnecessary complexity.

Macs Fan Control is a specialized utility for managing your Mac's cooling fans. While it's free for personal use, it focuses specifically on fan control rather than general system monitoring. You can create custom fan curves based on specific temperature sensors, set minimum and maximum fan speeds, and configure different profiles for different usage scenarios.

This is essential for power users who want to prevent thermal throttling during heavy workloads, reduce fan noise during light tasks, or maximize cooling when gaming or rendering. Macs Fan Control works perfectly alongside Stats or other monitoring tools—use Stats to monitor system metrics and Macs Fan Control to actively manage cooling. The app supports all Mac models from 2006 onwards, including Apple Silicon Macs, and provides granular control over every fan in multi-fan systems like Mac Pro and iMac Pro. For users who push their Macs hard with CPU-intensive tasks, video editing, or 3D rendering, Macs Fan Control can prevent thermal throttling that would otherwise reduce performance by 20-40% during sustained loads.

iGlance is another open-source menu bar system monitor that emphasizes visual appeal. It provides CPU, memory, network, battery, and disk monitoring with a focus on beautiful design and smooth animations. Written in Swift with a modern SwiftUI interface, iGlance offers customizable themes, graph styles, and icon designs that can match your desktop aesthetic.

The app supports transparency effects, blur backgrounds, and custom color schemes, making it one of the most visually customizable system monitors available. iGlance is particularly popular among designers and creative professionals who want system monitoring that doesn't clash with their carefully curated desktop environment. The app includes built-in themes for popular color schemes like Solarized, Nord, and Dracula, and you can create custom themes with specific colors for each metric. iGlance strikes a balance between Stats' feature richness and eul's minimalism, offering substantial functionality with a strong emphasis on aesthetic presentation.

DiskSight specializes in one thing: showing your available disk space in the menu bar. While general system monitors include disk space as one of many metrics, DiskSight provides detailed disk monitoring with support for multiple volumes, network drives, and external storage. The app displays used/free space as percentages or absolute values, shows color-coded warnings when drives are nearly full, and provides quick access to disk cleanup tools.

DiskSight is particularly valuable for users who work with large files—video editors, photographers, and developers who need to monitor storage across multiple drives simultaneously. The app can track Time Machine backup volumes, external SSDs, network attached storage, and cloud-synced folders like Dropbox or iCloud Drive. DiskSight's notifications alert you before you run out of space during large file operations, preventing failed renders or incomplete backups. For users who constantly juggle storage across multiple drives, DiskSight provides specialized functionality that general system monitors don't match.

MenuBar Stats is a straightforward system monitor that puts CPU, memory, disk, and network information in your menu bar with minimal fuss. The app takes a no-nonsense approach—install it, choose which metrics to display, and forget about it. Unlike feature-rich alternatives like Stats, MenuBar Stats focuses on delivering core monitoring functionality with the smallest possible resource footprint.

The app is particularly suitable for older Macs or users who run memory-intensive applications and can't spare resources for elaborate monitoring tools. MenuBar Stats uses native macOS APIs exclusively, avoiding third-party frameworks that would increase memory usage. The app's simplicity means there's no learning curve—every feature is self-explanatory and accessible from the menu bar dropdown.

For users who just want basic monitoring without complexity, configuration, or visual customization, MenuBar Stats delivers exactly what's needed and nothing more. The app receives periodic updates for macOS compatibility but doesn't chase new features, maintaining its core mission of lightweight, reliable monitoring.