Comparison

Foldmeter vs DuoCorder+

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

Head to head
About

Foldmeter

Features
Read full description

Foldmeter turns your iPhone into a measuring tool – and your iPhone Duo into a folding rule: unfold it and the app shows its angle to the degree, live as you fold. ON EVERY IPHONE • Ruler: Centimeters or inches along both screen edges. • Diameter: Lay a screw or drill bit on the screen, drag the lines to its edges, read the size – with a hint for the matching thread size (e.g. M6 or 1/4″). • Protractor: Place an object on the screen, drag the arms to its edges, read the angle. • Level: Upright for shelves and picture frames, flat as a bubble level for tables and surfaces. ON IPHONE DUO • Hinge angle: Your Duo's angle in large digits, with a side view of the device. • Hold values: Keep up to three readings and compare them. • Ruler and diameter on both the inner and the outer display. PRIVACY No ads, no tracking, no account. All readings stay on your device.

About

DuoCorder+

Transform your iPhone into a handheld sensor scanner. Explore environmental data like sound, air pressure, and magnetic fields with a retro-futuristic interface. Set custom alerts and track 24-hour trends for your sensor readings.

Highlights
  • Live sensor scanning
  • Retro-futuristic display
  • Customizable alerts
  • 24-hour trend charts
  • Metal detector mode
  • Data export (CSV)
  • Privacy-focused design
Features
Read full description

DuoCorder turns your iPhone into a handheld sensor scanner. See what your phone can sense about the world around you, live, on one retro-futuristic display. ONE-TAP FULL SCAN Press SCAN and DuoCorder samples every sensor for ten seconds, then explains what it found in plain language: "No magnetic anomalies", "Air pressure falling", "Conversation-level sound". Save the report or share it. MORE THAN A DOZEN LIVE INSTRUMENTS • Motion: acceleration, rotation, tilt and a bubble level • Compass: true and magnetic heading, 3-axis magnetic field strength • Air pressure: barometer, sea-level pressure, altitude change, pressure trend (iPhones with a barometer) • Light: ambient light level estimated from the camera's exposure • Sound: level in decibels, a live spectrum, and a scrolling spectrogram • Pitch: names the strongest note you hear, with how sharp or flat it is • Position: coordinates, speed, course, accuracy and the nearest place name • Activity: steps, distance, floors climbed, cadence and pace • Bluetooth radar: nearby devices, signal strength and a rough range estimate • Your phone: battery, CPU, memory, storage, temperature and network METAL DETECTOR MODE Sweep the phone slowly and listen. The tone rises in pitch and the haptic ticks speed up as the magnetic field changes near metal. YOUR OWN ALERTS Create rules such as "pressure falling faster than 2 hPa/hour", "magnetic field above 70 µT" or "battery below 20%". DuoCorder chirps, buzzes and flashes the screen when one triggers, and keeps a history of recent alerts. Alerts work while the app is open. 24-HOUR TRENDS DuoCorder records your readings while it is open and keeps the last 24 hours. Chart any sensor over 5 minutes to a full day, drag to inspect values, and see your alert thresholds on the chart. SNAPSHOTS AND SHARING Save a snapshot of any page, with your location, then browse your log or export everything as a CSV file. Share a full readable report in one tap. EASY TO LEARN Tap any reading to see what it means, view its trend or set an alert. A quick guide explains the controls, and every button is clearly labelled. BUILT FOR BIG AND FOLDABLE SCREENS The layout fills iPhone, iPad and wide two-panel displays, with the display on top and the keys below. PRIVATE BY DESIGN Everything stays on your device. There are no accounts, no ads, no analytics and no tracking. The microphone, camera and Bluetooth run only while the page or scan that needs them is open. Sound is analysed live and never recorded. The camera is used only for its light reading, and no photos or video are saved. GOOD TO KNOW Readings come from your phone's built-in sensors and are approximate. Which sensors you see depends on your device; for example, the barometer is not in every iPhone. DuoCorder is for curiosity and learning, not for medical, safety, navigation or professional use.

Screenshots

Foldmeter4 screens
DuoCorder+4 screens

Verdict

The call

The clearest difference is price: Foldmeter at $0.99 against DuoCorder+'s $2.99. DuoCorder+'s advantage is iOS requirement (17.0 vs 26.6). On ads, in-app purchases 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

Foldmeter costs $0.99 and DuoCorder+ $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Scorecard2 real differences · 6 level
Foldmeter versus DuoCorder+: the parameters behind the verdict, then further details
ParameterFoldmeterDuoCorder+
Price$0.99 — better$2.99
Rating—5.0 (1 ratings) — better
Number of ratings—1 — better
AdsNoNo
In-app purchasesNoNo
Monetization—Paid
DevicesiPhoneiPhone, iPad — better
Requires iOS26.617.0 — better
Further details — not scored
Size1 MB1 MB
Age rating4+4+
DeveloperappRabauken GbRJames Roche

In-app purchases

None

Foldmeter

No in-app purchases

None

DuoCorder+

No in-app purchases

Questions

Is Foldmeter free?
Foldmeter costs $0.99, with no in-app purchases.
Is DuoCorder+ free?
DuoCorder+ costs $2.99, with no in-app purchases.
Do Foldmeter or DuoCorder+ have ads?
Neither Foldmeter nor DuoCorder+ shows ads.

Other comparisons