Four To Twenty is a specialized utility calculator for industrial 4-20mA signal loop conversions on iOS.
The App DNA
What makes this app unique?
Technicians hire this tool for rapid, field-ready signal scaling that avoids the overhead of complex, general-purpose scientific calculators.
For Industrial technicians and engineers requiring quick field calculations for 4-20mA signal loops.
What does it look like?
Key features
Calculates process signal values from 4-20mA electrical inputs
Allows manual entry of signal ranges beyond presets
Provides 8 distinct visual themes for the interface
How much does it cost?
Paid model anchored at $0.99, capturing revenue through a one-time transaction for specialized industrial utility.
Velocity
Steady developmentShow more...
Who built it?
Jon Giambattista
7 apps tracked · Utilities
Worth - Hourly Wage Timer
IIFYM Macro/Calorie Calculator
EQD2 Calculator
CORAL Gyne Nomogram Calculator
Wallpaper Maker and Generator
CORAL: Prostate Cancer Risk and SurvivalUser Sentiment
What do users think recently?
The recent review mood reads excited. Users appreciate the application provides a straightforward and accessible experience for users performing basic mathematical calculations.
How are ratings & reviews evolving?
What users say, by theme
- The application provides a straightforward and accessible experience for users performing basic mathematical calculations
2 of 2 recent reviews analyzed · limited sample
Read the full review analysisUnlock 2 user requests, each backed by review evidence.
Access the full report for freeCompetition
Competitive landscape for Four To Twenty: mA/V Converter
How's the Utilities market?
The app maintains a niche presence in the Utilities category, ranking #77 Paid in the US. The $0.99 price point creates a barrier against free, comprehensive engineering suites that dominate the category.
Read the market outlookThe rivals identified
By Joshua Cotton
Both apps target industrial technicians and engineers requiring signal loop and transducer calibration, creating direct competition for the same professional field-tool use case.
- Four To Twenty: mA/V Converter offers eight visual themes; SENSOR TOOL LITE lacks aesthetic customization options.
- Four To Twenty: mA/V Converter charges $0.99; SENSOR TOOL LITE provides free access to core interpolation logic.
- SENSOR TOOL LITE functions as a lead-generation asset; Four To Twenty: mA/V Converter operates as a standalone paid utility.
Unlock the head-to-head verdict: where this rival wins, and where it loses.
Access the full report for freeThe Analyst's Read
Key takeaways for Four To Twenty: mA/V Converter
Where is it heading?
The industrial utility market is consolidating around multi-tool suites that offer higher daily value than single-purpose calculators. This app remains stable but exposed, so the PM must add professional-grade features like formula transparency to prevent churn to free competitors.
- Recent updates added support for negative numbers, showing active maintenance of the core calculation engine.
- The $0.99 price point faces increasing pressure from free, comprehensive engineering suites, which limits the app's growth potential.
The SWOT
- Simple interface reduces cognitive load for field technicians
- 8 visual themes provide aesthetic differentiation in a utilitarian category
- Integration of percentage-based range mapping would capture users needing to interpret partial signal values
Next best moves
Expose underlying math formulas because users request logic transparency → increase professional utility
+ 1 more prioritized moveThe counter-intuitive read
The app's simplicity is its greatest weakness…
Read the full takeFeature gaps
Comprehensive engineering reference library (available in Engineers Toolbox but absent here) +1
Since the last report: The report transitioned from a basic utility description to a detailed competitive analysis, highlighting active development and a strategic pivot toward freemium and formula transparency.
Bottom line
The app succeeds as a simple, dedicated tool, but its paid model is vulnerable to free, feature-rich engineering suites, so the PM should pivot to a freemium model and add formula transparency to secure professional adoption.
Unlock 2 critical frictions, 1 market threat, 1 more prioritized move and the analyst’s take.
Access the full report for freeReport last updated