Comparison

Gauge vs TBM Boldface

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

Head to head
About

Gauge

Prepare for wastewater operator certification exams with a focus on the math section. This app offers free calculators for essential formulas and provides step-by-step solutions to common mistakes. Practice with timed exams that mirror the actual test format and weighting.

Highlights
  • Free operator math calculators
  • Step-by-step worked solutions
  • Timed practice exams
  • Formula selection drills
  • Offline functionality
  • Exam blueprint adherence
Features
Read full description

Independent wastewater-operator study aid, not affiliated with WPI/ABC or any certifying authority. Its Class III practice form follows an older WPI/ABC outline, not WPI's revised 2025 outline. Check which exam your state or province administers. THE CALCULATORS ARE FREE Forty-nine interactive calculators and one geometric-mean reference cover flow and volume, detention and loading, process control, solids, chemical feed, pumping, power, and laboratory math. Each card shows a relationship, a practical note, and a common mistake. The geometric-mean card does not calculate; use your permit's specified method and zero-count rule. No account or advertising. FORMULA SELECTION PRACTICE WPI/ABC standardized wastewater exams provide a Formula/Conversion Table; other exams may differ. Two-stage questions let you choose a relationship, then compute a value while carrying units through. WORKED SOLUTIONS Calculation items show worked steps with units. The app can flag some common unit and magnitude slips, such as omitting 8.34 pounds per gallon, as study feedback rather than an official grading judgment. OLDER CLASS III PRACTICE MODEL The timed form uses five areas and 15 scored calculation items from WPI/ABC's previous Class III outline. WPI's revised 2025 outline has four areas and 14 percent calculation items; your certifying authority determines which exam you actually take. This app's form always adds ten unscored practice items, while WPI says a real exam may contain up to ten. The separate math score is personal feedback, not a certification prediction. SOURCES AND LIMITS The app includes authored explanations and cites regulations where relevant. Use current permits, plant procedures, approved methods, and your certifying authority's materials for real-world work. Report suspected errors through the Support link. WORKS WITH NO SIGNAL Study content and calculators are bundled on the device. Purchases, restores, and links to outside resources may need a connection. FREE, AND WHAT THE UNLOCK ADDS Free: 49 interactive calculators, the geometric-mean reference, and 88 practice questions drawn from five study areas. The one-time unlock opens the complete question bank, worked solutions, timed forms, formula-selection drills, spaced repetition, and area-by-area results feedback. One payment, no subscription, no account.

About

TBM Boldface

Features
Read full description

TBM Boldface is a free training aid for Daher TBM pilots. Study and test Section 3 memory items for your airplane — 700 A/B through 980 — filtered by serial and MOD. Daher does not print the word boldface. They print memory items (grey box in the 900–940 books, bold type in the 960 and 980). We treat those as boldface. Study shows every step on one page so you can chair-fly. Test is write the whole procedure on paper (or recite), then reveal. One card a day, plus Keep going for the rest of the pack. Optional daily reminder at a time you choose. Quick Ref covers Section 2 limits, V-speeds at MTOW/MLW, and engine exceedance thresholds for 700–940. Progress stays on your device and iCloud. No account besides your Apple ID. This is not a substitute for your serial-specific PIM, AFM, or POH. We do not ship the manual. If a step or number does not match your book, trust the book. Brought to you by PlaneWX.

Screenshots

Gauge4 screens
TBM Boldface4 screens

Verdict

The call

The clearest difference is in-app purchases: TBM Boldface at none against Gauge's 1. TBM Boldface also leads on update cadence (every 5 days vs every 2 weeks). On price, ads, 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

Both are free to download. Gauge sells 1 one-off in-app purchase. TBM Boldface asks for nothing beyond the download.

UpkeepUpdate frequency

Gauge ships an update every 2 weeks, TBM Boldface every 5 days. The most recent releases landed on October 19, 2026 and October 24, 2026 respectively.

Scorecard2 real differences · 7 level
Gauge versus TBM Boldface: the parameters behind the verdict, then further details
ParameterGaugeTBM Boldface
PriceFreeFree
Rating—5.0 (1 ratings) — better
Number of ratings—1 — better
Update frequencyEvery 2 weeksEvery 5 days — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases—
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.017.0
Further details — not scored
Size9 MB4 MB
Age rating4+4+
DeveloperOMAR DANIEL GRAZIANOMARK WALLACE WOLFGANG

In-app purchases

1 purchases

Gauge

One-time1
  • Full Unlock$14.99
None

TBM Boldface

No in-app purchases

Questions

Is Gauge free?
Gauge is free to download, with in-app purchases available.
Is TBM Boldface free?
TBM Boldface is free to download, with no in-app purchases.
Do Gauge or TBM Boldface have ads?
Neither Gauge nor TBM Boldface shows ads.
Which is updated more often, Gauge or TBM Boldface?
Gauge ships an update every 2 weeks, and TBM Boldface every 5 days. Most recently, Gauge was updated on October 19, 2026 and TBM Boldface on October 24, 2026.

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