Reverse Polish Notation Calculator
About this app
Simple fixed-point decimal arithmetic, Reverse Polish Notation calculator. RPN calculators may be in the minority but they are easy to learn and very efficient. The idea is that the operator follows the operands, so that instead of typing 2 + 2 =, one types 2 enter 2 enter +. The left arrow either deletes the last digit or drops the last item from the stack. The up arrow show a few other functions such as setting the number of decimal points, swapping items on the stack and the use of exponents.
Licensed under GPL-3.0-or-later, by ATH0.
What's New in v2.0.4
Imported from the F-Droid repository index.
Version history
Jun 12, 2024 · 0.2 MB · Android API 15–32 · code 18
Imported from the F-Droid repository index.
SHA-256 52e1f234710ebdf087e6760d0a0e4ff5d969f142b44ab61d1ce05ff526bd2bda
Oct 11, 2012 · 0.1 MB · Android API 14–14 · code 17
Imported from the F-Droid repository index.
SHA-256 3260c37df4a046a03c0497ffe86de697af9866772dcd765bb1c6841abb52b0e8
Jul 26, 2012 · 0.1 MB · Android API 14–14 · code 15
Imported from the F-Droid repository index.
SHA-256 bd0c35b0b57f0659c876194f0a3c9ec8c83b29d3d1d492240a20b7f12f4d19aa
Will it run on your device?
73%
- Runs on a broad range of modern Android versions.
- ABI coverage is focused on newer 64-bit devices.
Installation Guide
Open Settings on your Android device
Go to Security → Unknown sources (or Install unknown apps)
Enable "Allow from this source" for your browser or file manager
Open the downloaded APK file from your Downloads folder
Tap "Install" and wait for installation to complete
Launch the app from your home screen
Make sure to re-enable Unknown Sources restrictions after installation for security.
How to install this safely
How to verify the file you downloaded
Before you install anything, confirm the file is the one described here. On a computer, run shasum -a 256 your-download.apk (macOS or Linux) or certutil -hashfile your-download.apk SHA256 (Windows), then compare the output character-for-character with the SHA-256 on this page. If a single character differs, the file is not the build we recorded — delete it.
What the signing certificate proves
Every Android app is signed with a private key that only its developer holds. The fingerprint on this page is a hash of the matching public certificate, and it proves continuity rather than identity: it tells you a build came from whoever signed the earlier ones. Android enforces this at install time — if a package claiming to be com.ath0.rpn is signed with a different key, the system will refuse to install it over your existing copy. A fingerprint that changes between releases is worth pausing on, because a repackaged app that has been modified by someone else cannot keep the original signature.
How to roll back to an earlier version
If the current release misbehaves, 2.0.3 is the last build before it. Android will not install an older version code over a newer one, so you must uninstall RPN first — which clears its local data unless you have a backup. Reinstall the older APK only if its signing fingerprint matches the build you already trust, and check the API range: an older release may target an Android version your device has moved past.
Why we list sources instead of hosting everything
The official store channel is almost always the right choice: it updates automatically and carries the publisher's own distribution guarantees. A direct APK is useful when a device has no store access, when a rollout has not reached your region, or when you need a specific version — and only when the publisher has authorized that copy. APKBrowse does not list pirated, cracked, or unauthorized rebuilds of RPN, and a listing is removed when the evidence for it stops holding up.
Get RPN
Every source we list for com.ath0.rpn is legality-reviewed. Pirated or cracked builds are never offered.
Other sources
F-Droid listing
officialF-Droid builds this app from source and signs it. This is its official listing, with older builds and full release notes.
Source code
verified publisherThe upstream repository this build is compiled from.
We check legality and signature continuity, but device behaviour still varies. Install at your own discretion.
App Information
Security Verification
We record provenance; we do not run malware scans. Verify the hash yourself before installing.
SHA-256 Hash
52e1f234710ebdf087e6760d0a0e4ff5d969f142b44ab61d1ce05ff526bd2bda
Signing certificate
79c38d747ee9775d40a7d6911b31a0ccc7ce61c31b1d9bdef083723ec01e9ebb
Permissions Required
What each permission lets RPN do. A highlighted one is worth a second look — not necessarily wrong, just worth asking whether this app needs it.
Previous Versions
The signing certificate fingerprint for this release is on record, so a build that does not match it did not come from this publisher.
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