Comparison

pdf vs InductorCalc

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

Head to head
About

pdf

Manage and annotate PDF files on your iPad with fast page turning and intuitive finger-writing. Easily import, organize, and share your notes with friends. Offers a seamless reading and editing experience.

Highlights
  • Fast page turning and content scanning
  • Intuitive finger-writing with zoom-in
  • Easy PDF import via Dropbox, Email, or iTunes
  • Organized bookshelves with search
  • Variety of pens, highlighters, and text notes
  • Export annotated PDFs via email
Features
Read full description

Utilize pdf-notes to manage all the pdf files on your iPad. Fast display, quick page-turning even a thousand pages, useful finger-writing and email your notes to your friends. Differentiation-1. While turning pages of paperbooks fast, you can glance over the pages. While turning pages of pdf-notes fast, you can still run over the contents. Speedy page turning and scanning the contents with pdf-notes or paperbooks. Differentiation-2. There are many pdf readers allow you to annotate; but do you know which app allows you can write any notes in a second? If you are using pdf-notes, you may experience very fast and intuitive finger-writing like: zoom-in and note by double-tap or; writing with one finger, page-turning with two fingers, pen-changing with three fingers. - Easy importing PDF files through (DropBox, Email or Safari's) "Open In..." or iTunes - Categorized multiple bookshelves(booklists) with powerful search - Displaying pages as optimized size 1024x768 of iPad - Portrait and landscape view - Pinch zoom and crop page-margins - Fast loading and Speedy page-turning - Finger-writing with a variety of pens, highlighters and text notes - Easy "zoom-in and note" on a magnified screen by a double tap - One-step page-turning using 2 fingers on editing mode - One-step pen-changing or undo/redo using 3 fingers on editing mode - Exporting annotated PDF files to Email - External display and screen brightness controls - AirPrint and multi-tasking Misunderstandings about pdf-notes: - Not only pdf-notes but every app recently updated is removed from the open-in menu because iOS5 or formers currently show only 10 apps in open-in menu. - iPad/iphone Mail/iBooks can't display PDF annotations so that please open it in the other pdf apps. - please visit the support site for more information http://bit.ly/f6D31P Blog http://pdf-notes.com Email musebook@musebook.com Twitter http://twitter.com/musebook4u YouTube http://youtu.be/4AyRyFq9yxg NOTE: All content contained herein is subject to change without notice.

About

InductorCalc

Calculate essential parameters for custom inductors and coils. Input dimensions like turns, length, and diameter to instantly get inductance, Q-factor, wire length, and DC resistance. Ideal for electronics enthusiasts and students designing custom components.

Highlights
  • Calculate inductance (L)
  • Calculate Q-factor at operating frequency
  • Calculate total wire length
  • Calculate DC resistance
  • Supports multiple SI units
Features
Read full description

Designing your own inductor or coil? InductorCalc makes it quick and easy to get the key parameters you need. Enter your coil’s physical dimensions — number of turns, length, and diameter — and instantly calculate: • Inductance (L) in a range of SI units • Q-factor at your chosen operating frequency • Total wire length needed for the winding • DC resistance based on your wire’s Ω/m value Simply fill in the fields, tap Calculate, and let the app do the math. Perfect for electronics hobbyists, students, and anyone building custom inductors.

Screenshots

InductorCalc4 screens

Verdict

The call

The clearest difference is price: InductorCalc at $0.99 against pdf's $9.99. InductorCalc also leads on review sentiment (100% vs 79%) and device support (3 vs 1). pdf's advantage is update cadence (every 2 weeks vs every 23 months). On ads, in-app purchases and monetization model 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

pdf costs $9.99 and InductorCalc $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

pdf ships an update every 2 weeks, InductorCalc every 23 months. The most recent releases landed on June 10, 2026 and September 28, 2026 respectively.

Scorecard5 real differences · 5 level
pdf versus InductorCalc: the parameters behind the verdict, then further details
ParameterpdfInductorCalc
Price$9.99$0.99 — better
Rating4.4 (27 ratings) — better—
Positive reviews79.2% of reviews100.0% of reviews — better
Number of ratings27 — better—
Update frequencyEvery 2 weeks — betterEvery 23 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
DevicesiPadiPhone, iPad, iPod — better
Requires iOS16.012.0 — better
Further details — not scored
Size138 MB17 MB
Age rating4+4+
DeveloperAMuseTec Co., Ltd.oskari saarinen

Customer experience

pdf

All ratings27 ratings
Positive85.2%
Neutral7.4%
Negative7.4%
Written reviews96 reviews
Positive79.2%
Neutral6.3%
Negative14.6%

InductorCalc

Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

pdf

No in-app purchases

None

InductorCalc

No in-app purchases

Questions

Is pdf free?
pdf costs $9.99, with no in-app purchases.
Is InductorCalc free?
InductorCalc costs $0.99, with no in-app purchases.
Do pdf or InductorCalc have ads?
Neither pdf nor InductorCalc shows ads.
Which is updated more often, pdf or InductorCalc?
pdf ships an update every 2 weeks, and InductorCalc every 23 months. Most recently, pdf was updated on June 10, 2026 and InductorCalc on September 28, 2026.

Other comparisons