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Free42

Free#11 of 32 in Scientific Calculator Apps

Free42: A free HP-42S-style simulator for programmable calculations across desktop and mobile. Ranked #11 of 32 in Scientific Calculator Apps by our editors (7.5/10); pricing: Free plan; best for users who want an HP-42S-style programmable calculator.

7.5/10Editor score
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At a glance

  • Editor score
    7.5 / 10
  • Pricing
    Free plan
  • Best for
    Users who want an HP-42S-style programmable calculator
  • Free plan
    Yes
  • Paid from
    None
  • Platform support
    Cross-platform
  • Facts checked
    28 Sep 2026

  • Where it wins

    • Runs HP-42S programs and simulates the HP-82240 printer
    • Supports real and complex numbers, plus real and complex matrices
    • Free, open source, and available on desktop and mobile

  • Where it doesn't

    • Focuses on HP-42S simulation rather than broad equation solving
    • Does not provide equation solving
    • Its programmable calculator approach may not suit users seeking graphing

Our verdict on Free42

Free42 reimplements the HP-42S scientific programmable calculator and HP-82240 printer as software, for people who want an HP-42S-style calculator on desktop or mobile. It can run programs written for the HP-42S and supports user-written programs, making it relevant to users who want programmable calculations rather than a general equation-solving or graphing app. The project is open source under GPLv2 and has downloads for Windows, macOS, Linux, iOS, and Android.

Its feature set goes beyond basic real-number calculations: Free42 supports complex numbers and real and complex matrices. It provides decimal and binary floating-point versions, date and time functions, and configurable BASE operations. Users can import and export programs, copy and paste them, and save, share, or switch calculator states. Those capabilities make it a focused option for users who value an HP-42S workflow and reusable programs; they do not make it a broad equation-solving tool.

Free42 is free, with no paid tiers to weigh against those capabilities. Its cross-platform availability lets users keep the same calculator approach across desktop and mobile, while its email, community, and documentation channels provide support routes. The trade-off is its deliberate focus: it simulates the HP-42S rather than offering equation solving or graphing. Choose Free42 for programmable HP-42S-style calculations, complex arithmetic, and matrices; look elsewhere if equation solving or graphing is central to your work.

Free42 pricing

Plans Free planFree Free to use — no paid tier required for the core job.
See plans on thomasokken.com

Free42 fact sheet

Free planYes
Paid fromNone
Platform supportCross-platform
Equation solvingNo
Statistics toolsYes
Programmable functionsYes
Complex numbersYes
Offline modeNot verified
Matrix operationsYes
DeploymentDesktop, Mobile
PlatformsWindows, macOS, Linux, iOS, Android
SupportEmail, Community, Docs
Built forSolo (editorial estimate)
PricingFree plan
Websitethomasokken.com
Facts checked28 Sep 2026

Alternatives to Free42

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Featured on iTechGuides

Featured on iTechGuides — Free42 7.5/10

Free42 is listed in our Scientific Calculator Apps directory. Add the badge to your site — it links back to this page.

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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