a free iStat Menus alternative
updated · by Anton Shakirov
iStat Menus has been the reference system monitor for macOS for over a decade, and it costs $11.99 once. hop shows the numbers that explain a hot, slow or draining Mac — as one of eighteen tools behind a single menu bar icon, for nothing.
if you read the menu bar as an instrument panel all day and want every sensor with months of history, that is what iStat Menus is built for. this page is for the person who checks temperatures when the fans spin up, and would rather not run a separate app for that.
what iStat Menus gets right
depth, and years of it. more sensors, longer history, far more configuration, and a decade of refinement around one job. people do want per-core frequencies, fan curves and disk benchmarks in the menu bar, and iStat Menus serves them.
it is also the app that made this a category. measuring is what it does, not a tab inside something else, not a module. monitoring in hop is one of eighteen tools, built to the depth one of eighteen gets, and this page is not going to pretend otherwise.
the price is $11.99, one payment, checked against its Mac App Store listing on 10 september 2026. for a tool you look at daily that is not the expensive part of anything.
what macOS gives you, and what it gives nobody
both apps are working around the same thing, and knowing what it is changes the question. on Apple silicon, macOS does not hand out cpu or gpu temperature at all: not to the interface, not to a command, not to a command run under sudo.
the full walk through what does and does not work on the command line, with the output of each attempt, is on its own page — check cpu temperature on an Apple silicon Mac
why no app can just read the sensor
checked on macOS 26.6.2: `sysctl -a | grep -c therm` returns zero. not one key. `ioreg` lists the sensors, dozens by name, and exposes a value for none of them. the `sudo powermetrics --samplers smc` recipe that every page copies answers «unrecognized sampler: smc», an Intel sampler that did not survive the move.
so neither app is reading a number macOS was ready to give. both do something the system does not, which moves the question from «why pay for this» to «how much is the same reading worth».
what you can read for free right now
macOS does publish one thing: a thermal pressure level, readable by any user with no sudo and no app at all. run `notifyutil -g com.apple.system.thermalpressurelevel` and read the number at the end of the line. 0 is nominal.
the other is battery temperature, the only numeric temperature on the machine. `ioreg -rc AppleSmartBattery | grep Temperature` gives hundredths of a degree, so 3098 is 30.98 °C. useful, and not the chip.
neither gives you a trend, a warning, or the number you came for. thermal pressure is a state you have to go and ask for, one reading at a time.
the same thing in the form applications see it, which is why no app can show you a «real» number either: ProcessInfo.ThermalState
and if the reason you are here is noise rather than numbers, the fan is not reacting to what you are doing now, which sends people looking for the wrong reading — why your Mac fan is loud
so what should you actually install
if the question is binary, «is this thing throttling right now», the command above answers it and nothing needs installing. that is the whole simple case, and plenty of people never leave it.
the simple case ends the moment you want the answer without asking for it: a number rather than a level, a graph rather than a snapshot, something that tells you before the machine has visibly gone slow. from there it is an app, and the question is which one and at what price.
there is also a field of free dedicated monitors, several of them open source, and they do this job well. it would be strange of us to hide that. the difference is shape: a dedicated monitor is another menu bar icon doing one thing, and hop is eighteen tools sharing one.
where hop is different from iStat Menus
it stays quiet. values light up only when they leave the range you set, and the warning can sit on the menu bar icon itself. a monitor showing eight numbers at all times stops being read after a week. behind it: cpu and gpu load with temperatures, memory and swap, network, disk, battery health and cycles, power draw, uptime, each with an hour of graph.
the number most monitors do not show
the memory row speaks up when a lot of memory has gone to disk, not only when macOS reports being short. that is usually why a Mac feels sluggish while memory looks free. the machine is not out of memory, it is busy moving it.
what the figure macOS shows you instead actually measures, and why it is a state rather than a number: what memory pressure actually measures
| what you came for | the free route | with hop |
|---|---|---|
| just want to know whether it is throttling | notifyutil, one line, nothing installed | not needed — keep the command |
| want the actual number, not a level | no command gives it; an app is the only way | cpu and gpu temperature next to load |
| want to know it got hot while you were away | you had to be asking at the time | the last hour, as a graph |
| want to be told rather than to look | nothing to set a threshold on | your own thresholds, warning on the icon |
| the Mac feels slow and memory looks fine | read pressure and infer | the memory row says when it went to disk |
| you also wanted a timer, a clipboard, a converter | an app each, an icon each | seventeen more behind the same icon |
why the free route reports a state and not a figure here too — Apple's own description of the memory pressure graph: view memory usage in Activity Monitor
when the reading turns into an actual error message rather than a slow afternoon, that has its own procedure — fix «your system has run out of application memory»
the module on its own, including what it watches besides temperature: system monitor
what you give up leaving iStat Menus
granularity and history. hop shows the last hour, not the last month, and it does not expose every sensor your Mac has. if you diagnose thermals for a living, that is a different tool and iStat Menus is built to be it.
you also give up specialisation. an app that has done one job for a decade accumulates decisions a module does not get to make, and $11.99 is a fair price for them.
nothing above should be read as a list of things iStat Menus cannot do — we have not checked. what is written above is what hop does; compare it against your own list.
the other half of the trade is arithmetic in the menu bar: one icon covering eighteen jobs instead of eighteen icons that need hiding. a free Bartender alternative
how to try the alternative without deciding anything
- get hop — a five-megabyte download, no account needed, macOS 14+
- switch off everything except monitor, if the rest is not interesting
- set what counts as normal for your machine; a laptop that renders video should not be flashing red all day
- leave iStat Menus installed while you do it: nothing conflicts, and a week of both answers this better than the page does
- if it does not tell you what you need, drag it to the trash — nothing was registered and nothing was paid
and if you are weighing this up because the menu bar is already full, macOS 26 changed the rules for what fits there — what macOS 26 changed for menu bar apps
frequently asked questions
- does macOS have a built-in cpu temperature readout?
- no, and on Apple silicon it is stronger than that: the number is not available to a command either. checked on macOS 26.6.2, sysctl has no thermal keys, ioreg lists sensors without values, and the powermetrics smc sampler does not exist. free to read: a thermal pressure level, and the battery temperature.
- does it show cpu temperature?
- yes, next to cpu load, and the same for the gpu. macOS itself offers neither to any app, so both hop and iStat Menus are working around the same gap.
- is iStat Menus worth $11.99?
- if you want every sensor, months of history and deep configuration, yes. one payment, $11.99 on 10 september 2026, and nothing else goes as deep. the question is whether you want an instrument panel or a temperature reading when the fans spin up.
- how much history does it keep?
- graphs cover the last hour — enough to answer «why did the fans spin up two minutes ago», not enough for long-term analysis. iStat Menus goes much further back, and that alone is a reason to choose it.
- is there a free dedicated system monitor instead?
- several, and some are open source. if a monitor is the only thing you want, one of those is a fine answer. hop makes sense when monitoring is one of several things you want out of the menu bar rather than the whole of it.
- does monitoring slow the Mac down?
- it is built not to, and readings update only while the tab is open. a monitor that shows up in its own readings has failed at its only job.
- is hop really free?
- free and open source under MIT. no trial, no pro tier, no accounts and no telemetry.
the hop side of this
system monitor — load, temperatures, memory and battery — quiet until something is wrong.
about the author
Anton Shakirovmakes hop
makes hop and every page on this site. eighteen tools under a single menu bar icon, MIT licensed and open source. reads and answers issues and email himself.