Comparison

Kaliper 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

Kaliper

Measure key cuts accurately using your device's camera. This utility helps decode keys when a physical caliper is unavailable or difficult to read. Offers predefined systems and custom measurement options for various lock types.

Highlights
  • Measure key cuts with device camera
  • Predefined lock systems
  • Custom key measurement input
  • Ad-free upgrade option
  • Supports various lock brands
Features
Read full description

Out-of-the-shop and out-of-the-van key gauge utility. Have a key you need to decode but no caliper or key gauge nearby? Not 100% confident on your eyesight to read the cuts? Then use your iDevice to measure the key with Kaliper. Kaliper is free to download with a purchase option for upgrading. It is recommended to get accustomed to the app prior to purchasing as with any tool, this app has a learning curve and with practice comes perfection. The free version comes with two predefined systems: Arrow .014" and Schlage .015" (5 pin only). The full version comes with eight predefined systems: Arrow .014" (5/6 pin), Best A2, A3, A4 (6/7 pin), Kwikset .023" (standard/titan), Sargent .020" (5/6 pin), Schlage .015" (5/6 pin), and Yale .019" (5/6 pin). In addition to custom key measurements and of course no ads. Instructions: On the main page begin by selecting your iDevice from the choices on the left, then select either a predefined system or custom. Do not use full screen on iPads. 

Predefined: 

Lay your device on a flat surface and place your key on top of the silhouette, using the top shoulder (or bottom tip for best systems) as the primary focus for alignment. If aligned properly each of the cut markers will sit directly above each corresponding cut. If necessary, use the zoom control at the bottom for a better fit. Once the key is aligned, tap on the first down arrow in the upper right hand corner to lower the cut marker. Each tap represents a deeper cut with the depth displayed directly above the arrow. Keep tapping until the marker outlines the cut. If the marker starts to disappear behind the key use the up arrow to raise the marker. Do this for the remaining cuts to finish measuring your key. Custom: The measuring process remains the same as the predefined systems, but as the markers are customizable some measurements need to be supplied before proceeding: Bow to First Cut: The distance from the center of the first cut to the top shoulder. Cut to Cut: The distance between the center of each cut. Shallowest Depth: The distance from the bottom of the blade to the center of the lowest cut in the system (i.e. Zero or One). Depth Increment: The distance between subsequent cuts. These measurements are typically found on pinning kits, however the system you are inputting may be found on the Charts page. From this chart simply tap on the system and all the measurements will be automatically applied. If inputting manually, type the measurements into the 4 boxes and tap Apply. The markers will adjust accordingly and you can begin measuring the key using the shoulder and blade for alignment. If the system uses a One as the shallowest cut, tap on 0 - 9 to reflect a 1 thru 10 cut system. Tap again to switch back. Compatibility (sorted by screen size): iPhone SE2, SE3, 12 mini, 13 mini, 11 Pro, 11, 12, 12 Pro, 13, 13 Pro, 14, 14 Pro, 15, 15 Pro, 16, 16e, 17e, 16 Pro, 17, 17 Pro, Air, 11 Pro Max, 12 Pro Max, 13 Pro Max, 14 Plus, 14 Pro Max, 15 Plus, 15 Pro Max, 16 Plus, 16 Pro Max, 17 Pro Max 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

Kaliper4 screens
Black Widow Key Machine1 screens

Verdict

The call

The clearest difference is in-app purchases: Black Widow Key Machine at none against Kaliper's 1. Black Widow Key Machine also leads on ads (none vs shown) and update cadence (every 5 weeks vs every 8 months). Kaliper's advantage is ratings volume (8 vs 2). On price, rating and device support 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

Both are free to download. Kaliper sells 1 one-off in-app purchase. Black Widow Key Machine asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

On the App Store both sit at effectively the same score — 4.6 for Kaliper against 4.5 for Black Widow Key Machine. Both are backed by a comparable volume of ratings — 8 and 2 respectively.

UpkeepUpdate frequency

Kaliper ships an update every 8 months, Black Widow Key Machine every 5 weeks. The most recent releases landed on August 25, 2026 and September 6, 2026 respectively.

Scorecard6 real differences · 4 level
Kaliper versus Black Widow Key Machine: the parameters behind the verdict, then further details
ParameterKaliperBlack Widow Key Machine
PriceFreeFree
Rating4.6 (8 ratings) — better4.5 (2 ratings)
Positive reviews50.0% of reviews
Number of ratings8 — better2
Update frequencyEvery 8 monthsEvery 5 weeks — better
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchasesFree — better
DevicesiPhone, iPodiPhone, iPod
Requires iOS14.012.0 — better
Further details — not scored
Size4 MB149 MB
Age rating4+4+
DeveloperFarren DomeniciAmerican Key Supply

Customer experience

Kaliper

All ratings8 ratings
Positive87.5%
Neutral12.5%
Negative0.0%
Written reviews6 reviews
Positive50.0%
Neutral33.3%
Negative16.7%

Black Widow Key Machine

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

1 purchases

Kaliper

One-time1
  • Kaliper Full Version$1.99
None

Black Widow Key Machine

No in-app purchases

Questions

Is Kaliper free?
Kaliper is free to download, with in-app purchases available.
Is Black Widow Key Machine free?
Black Widow Key Machine is free to download, with no in-app purchases.
Which has better reviews, Kaliper or Black Widow Key Machine?
Kaliper is rated higher. Kaliper averages 4.6 out of 5 from 8 ratings, while Black Widow Key Machine averages 4.5 from 2 ratings.
Do Kaliper or Black Widow Key Machine have ads?
Kaliper shows ads; Black Widow Key Machine does not.
Which is updated more often, Kaliper or Black Widow Key Machine?
Kaliper ships an update every 8 months, and Black Widow Key Machine every 5 weeks. Most recently, Kaliper was updated on August 25, 2026 and Black Widow Key Machine on September 6, 2026.

Other comparisons