Comparison

A4Calc vs Black Widow Key Machine

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

Head to head
About

A4Calc

Features
Read full description

A4 Small Format Interchangeable Core Calculator (sister app of A2Calc and A3Calc) ---Programmed by a Locksmith, for Locksmiths--- Automatically calculates the pinning chart for A4 SFIC. Built for 6 or 7 pin systems, however, less can be achieved by using a decimal to erase a chamber. Minimum of a control and master key are required to make a chart. Additional change key available for all devices; 2 change keys available for 16:9 screen devices. Randomize function will generate completely random charts each time it is triggered. "Lock/Unlock" toggle disables/enables all inputs and functions to prevent unwanted/lost changes. Control Finder is an added bonus by reverse engineering a core to determine the control key's bitting. This is perfect when needing to remove multiple cores in a building when the control key has been lost. There are two methods for achieving the control key: 1. using the master, control, and bottom pins, or 2. using only the top/driver pins. Up to 16 different projects can be saved at any one given time. All projects are encrypted and protected with a passcode when stored on your device. All projects can be exported via AirPrint and Email. Compatibility: iPhone / iPod touch on iOS 8.0 or later and iPad on iOS 12.0 or later. Found a bug? Something not working? Have a suggestion? Feel free to contact me via email: farren@phoxlocks.com

About

Black Widow Key Machine

This mobile tool allows locksmiths to quickly cut various types of keys, including high-security, edge-cut, dimple, tibbe, and tubular blanks. It connects via Bluetooth to a mobile device for cutting keys by code, duplicating, and progression.

Highlights
  • Cuts high-security keys
  • Cuts edge-cut keys
  • Cuts dimple keys
  • Cuts tibbe keys
  • Cuts tubular keys
  • Bluetooth connectivity
  • Cut by code functionality
Features
Read full description

The Black Widow key machine is designed to quickly cut all keys a locksmith needs to run their business: high-security, edge-cut, dimple, tibbe, and tubular key blanks. Use your mobile device via Bluetooth to cut keys by code, duplicate, and progression your keys.

Screenshots

A4Calc4 screens
Black Widow Key Machine1 screens

Verdict

The call

The clearest difference is price: Black Widow Key Machine at Free against A4Calc's $4.99. Black Widow Key Machine also leads on update cadence (every 5 weeks vs every 8 months). 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

Black Widow Key Machine is free to download; A4Calc costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

A4Calc ships an update every 8 months, Black Widow Key Machine every 5 weeks. The most recent releases landed on September 30, 2026 and September 6, 2026 respectively.

Scorecard2 real differences · 7 level
A4Calc versus Black Widow Key Machine: the parameters behind the verdict, then further details
ParameterA4CalcBlack Widow Key Machine
Price$4.99Free — better
Rating—4.5 (2 ratings) — better
Number of ratings—2 — better
Update frequencyEvery 8 monthsEvery 5 weeks — better
AdsNoNo
In-app purchasesNoNo
Monetization—Free
DevicesiPhone, iPodiPhone, iPod
Requires iOS12.012.0
Further details — not scored
Size2 MB149 MB
Age rating4+4+
DeveloperFarren DomeniciAmerican Key Supply

In-app purchases

None

A4Calc

No in-app purchases

None

Black Widow Key Machine

No in-app purchases

Questions

Is A4Calc free?
A4Calc costs $4.99, with no in-app purchases.
Is Black Widow Key Machine free?
Black Widow Key Machine is free to download, with no in-app purchases.
Do A4Calc or Black Widow Key Machine have ads?
Neither A4Calc nor Black Widow Key Machine shows ads.
Which is updated more often, A4Calc or Black Widow Key Machine?
A4Calc ships an update every 8 months, and Black Widow Key Machine every 5 weeks. Most recently, A4Calc was updated on September 30, 2026 and Black Widow Key Machine on September 6, 2026.

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