Comparison

OTR Diagnostics vs Percently Quick Calculator

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

Head to head
About

OTR Diagnostics

This diagnostic tool helps heavy-duty truck owners understand and resolve fault codes, perform crucial maintenance tasks like regens, and monitor live engine data. It aims to reduce downtime and avoid costly dealer visits by empowering users with detailed insights and control over their vehicle's systems.

Highlights
  • Reset active and inactive fault codes
  • Perform forced DPF/SCR regens
  • Understand fault codes in plain language
  • Monitor live engine data
  • Track fault code history
  • Bi-directional commands for repairs
Features
Read full description

OTR Diagnostics — Trusted by 10,000+ Truck Owners Dealing with regen problems, nonstop alerts, fault codes, and unexpected derates on your heavy duty truck? You are not alone. More than 10,000 truck owners and fleets trust OTR Diagnostics to take control, cut downtime, and avoid expensive dealer visits. Powered by OTR Assist + OTR LINK 2 This is more than a scan tool. OTR Assist is your AI partner, breaking down fault codes in plain language and helping you troubleshoot and decide if you can keep driving or need service now. Paired with OTR LINK 2, our proprietary Bluetooth adapter, you get faster connection speeds, more accurate fault code data, and more live data parameters than ever before. It is 5X better than previous hardware. Ask us how to get a FREE upgrade today. Commands That Keep You Moving With bi-directional commands built right into OTR Diagnostics, you are no longer stuck waiting on a shop to do what you can handle yourself. Reset active and inactive fault codes Reset the entire aftertreatment system Reset derates that slow you down Reset soot levels after a DPF service Run forced DPF or SCR regens right from the cab These commands put you back in control, saving you time, money, and downtime. Fault Code Insights Go beyond a flashing dash light. OTR Diagnostics helps you understand fault codes with the same level of detail as dealer software, but in plain language you can actually use. Decode your dash lights Uncover the root causes of issues Track how often a problem occurs Know which repairs or parts are needed Live Data Monitoring Want to know if your regen is working? Want to monitor exhaust temps, soot levels, or DEF? OTR Diagnostics lets you see your truck’s vitals in real time so you can spot issues before they stop you. Common live data parameters include: DPF fluid level DPF soot level EGR valve position Aftertreatment exhaust temps Boost pressure Accelerator pedal position Engine fuel delivery pressure Available live data may vary depending on the engine model your device is connected to. Explore Your History Recurring problems? OTR Diagnostics logs every fault code and command so you can see when issues happened, when they were cleared, and how long regens lasted. Proven. Tested. Backed by Support We run OTR Diagnostics, OTR Assist, and OTR LINK 2 on our own fleet of test trucks including late model Paccar MX engines to make sure everything works before it reaches you. That is why more than 10,000 drivers already trust OTR Diagnostics. Made in Michigan. Built for You We engineer, assemble, and ship right from our shop in Macomb, MI. If you are nearby, stop in and see us. Coverage We support a wide range of heavy duty engines: Cummins: CM871, CM2150, CM2250, CM2350 (2008–2024) Detroit Diesel: DD60, MBE, DD13, DD15, DD16 (2008–2024) Paccar: MX11, MX13 (2011–2024), PX7, PX9 (2008–2024) Volvo: D11, D13, D13TC, D16 (2014–2024) Mack: MP7, MP8, MP8HE, MP10 (2014–2024) For the full list of compatible models, call or text us at 586-799-4375. Need Help or Have Questions? Call or text us anytime at 586-799-4375 or email support@otrperformance.com.

About

Percently Quick Calculator

Features
Read full description

Percently is a simple percentage calculator for everyday math. Quickly solve percent-of, percent-of-total, increase or decrease by percent, percentage difference, discounts, and tips in a clean, easy-to-use interface.

Screenshots

OTR Diagnostics4 screens
Percently Quick Calculator1 screens

Verdict

The call

OTR Diagnostics and Percently Quick Calculator are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

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. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

OTR Diagnostics ships an update weekly, Percently Quick Calculator every 8 days. The most recent releases landed on November 3, 2026 and October 31, 2026 respectively.

ScorecardNo meaningful differences
OTR Diagnostics versus Percently Quick Calculator: the parameters behind the verdict, then further details
ParameterOTR DiagnosticsPercently Quick Calculator
PriceFreeFree
Rating4.0 (99 ratings) — better—
Positive reviews55.2% of reviews—
Number of ratings99 — better—
Update frequencyWeekly — betterEvery 8 days
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.617.0 — better
Further details — not scored
Size268 MB2 MB
Age rating4+4+
DeveloperOTR PerformanceSacred Pathway LLC

Bugs and requests

OTR Diagnostics

Reported bugs

10 issues
  • App constantly disconnects from device
  • Generic code option disappeared
  • Forced regen is no longer consistent
  • AI assistant not working
  • App asks to do things not available in app
Show 5 more
  • Bluetooth connection rejects
  • App doesn't work without data connection
  • Forced regen not activating after updates
  • Login authentication errors
  • Cannot start regen process on newer models

Requested features

5 requests
  • Remember email address for login
  • Allow offline functionality without data connection
  • Add option to change speed
  • More detailed diagnostic information
  • Allow basic subscription to work on multiple VINs

Percently Quick Calculator

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

OTR Diagnostics

No in-app purchases

None

Percently Quick Calculator

No in-app purchases

Questions

Is OTR Diagnostics free?
OTR Diagnostics is free to download, with no in-app purchases.
Is Percently Quick Calculator free?
Percently Quick Calculator is free to download, with no in-app purchases.
Do OTR Diagnostics or Percently Quick Calculator have ads?
Neither OTR Diagnostics nor Percently Quick Calculator shows ads.
Which is updated more often, OTR Diagnostics or Percently Quick Calculator?
OTR Diagnostics ships an update weekly, and Percently Quick Calculator every 8 days. Most recently, OTR Diagnostics was updated on November 3, 2026 and Percently Quick Calculator on October 31, 2026.

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