PCalc vs Knot Guide HD
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PCalc
A powerful calculator designed for professionals and students, offering advanced features like RPN mode, multi-line display, and extensive unit conversions. It supports various number systems and includes an Apple Watch app for on-the-go calculations.
- Optional RPN mode
- Multi-line display
- Extensive unit conversions
- Paper tape
- Multiple undo/redo
- Hexadecimal, octal, binary support
- Apple Watch app
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PCalc is the powerful choice for scientists, engineers, students, programmers, or indeed anybody looking for a feature rich calculator. It includes an optional RPN mode and multi-line display, a choice of button layouts, an extensive set of unit conversions and constants, a paper tape, multiple undo and redo, engineering and scientific notation, as well as support for hexadecimal, octal, and binary calculations. Includes an Apple Watch app, so you can calculate on your wrist!
Knot Guide HD
Learn to tie over 100 different knots with clear, step-by-step instructions and photographs. This app categorizes knots for easy browsing and provides detailed descriptions for each one, making it a practical tool for various activities.
- 107 unique knots
- Clear, colorful photographs
- Browse by category or knot name
- Detailed knot descriptions
- Categorized knot library
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#1 Knot App on iTunes!!! Now with 107 knots and continuous new additions! An App Store Essentials "Weekend Warriors DIY" PICK! "Wow your friends!" - APPLEIPHONEAPPS.com "...a highly recommended app with tons of utility value..." - IPHONEAPPREVIEWS.net "What's knot to love?" - "THIS OLD HOUSE" - The Hardware Isle "Knot Guide is like a patient teacher... showing you over and over how to tie it until you’ve committed it to memory." - APPCRAVER.com "One of the most practical apps for those not bound by four walls..." - SAN FRANCISCO EXAMINER Need to tie a knot? Knot Guide will teach you the ropes! Knot Guide NOW includes the following 107 knots, 95 of which are unique: Adjustable Bend, Adjustable Loop, Albright Knot, Alpine Butterfly on a Bight, Anchor Bend, Arbor Knot, Ashley Bend, Ashley's Stopper, Bachmann Hitch, Back Splice, Barrel Hitch, Blake's Hitch, Blood Knot, Bowline, Bowline on a Bight, Braid Knot, Buntline Hitch, Carrick Bend, Chain Sinnet (Daisy Chain), Cleat Hitch, Cleat Hitch With Round Turn, Clinch Knot, Clove Hitch, Clove Hitch on a Bight, Constrictor, Countryman's Knot, Cow Hitch, Diagonal Lashing, Double Figure Eight Loop, Double Fisherman's, Double Overhand Stopper, Double Sheet Bend, Double Surgeon's Loop, Eye Splice, Figure Eight Follow Through, Figure Eight Knot, Figure Eight Loop, Fisherman's Bend, Fisherman's Knot, Flemish Flake, Four-in-Hand Knot, Gasket Coil, Girth Hitch, Hammock Hitch, Highwayman's Hitch, Honda Knot, Hunter's Bend, Improved Clinch Knot, Johnson Hitch, Jug Sling, Klemheist Knot, Lariat, Lark's Head, Lumberman's Knot, Monkey Fist, Mooring Hitch, Munter Hitch, Nail Knot, Orvis Knot, Overhand Knot, Oysterman's Stopper, Palomar Knot, Perfection Loop, Pile, Hitch, Poacher's Knot, Pratt Knot, Prusik Knot, Rapala, Reef Knot, Rigger's Bend, Right Angle Knot, Rolling Hitch, Rosendahl Bend, Rosendahl Loop, Round Lashing, Running Bowline, Running Knot, Sailor's Gripping Hitch, Sailor's Whipping, San Diego Jam Knot, Shear Lashing, Sheepshank, Sheet Bend, Simple Simon Under, Sledge Knot, Slim Beauty, Slip, Square, Square Lashing, Stevedore, Surgeon's Knot, Tautline Hitch, Timber Hitch, Trucker's Hitch (1), Trucker's Hitch (2), True Lover's Knot, Tumble Hitch, Turk's Head 3L5B, Turle Knot, Two Half Hitches, Uni Knot, Water Bowline, Water Knot, West Country Whipping, Yosemite Bowline, Zeppelin Bend, Zeppelin Loop 19 CATEGORIES include: Bends, Binding Knots, Climbing Knots, Decorative Knots, Fishing Knots, Hitches (End), Hitches (Middle), Lashings, Loops (Fixed), Loops (Slip), Navy SEAL Knots, Necktie Knots, Rope Care, Sailing Knots, Scout Knots, Shortenings, Splices, Stopper Knots, Whippings FEATURES: * Clear, colorful photographs * Browse search by category or knot name * From the "Knot Categories" screen, select a knot category (description and photo included for each category) * Next, select a specific knot from your chosen category (description and photo included for each specific knot) * Swipe the images to move forward or backward through the visual steps. * Save your favorite knots for easy access * "Knot Lingo" screen covers basic terms for knot tying. Please also check out Knot Guide for the iPhone. People of all walks of life since ancient times have found knots both fascinating and essential. Knots are used in sailing, climbing, tree trimming, jewelry making, and everyday tasks such as hitching a load to your vehicle. Whether you are a novice or you have experience with tying knots, Knot Guide will assist you! NOTE: Knots that are also known as another name are now also listed by the other name (eg. Square Knot is also listed as Reef Knot).
Screenshots
Verdict
The clearest difference is rating: PCalc at 4.7 against Knot Guide HD's 4.1. PCalc also leads on update cadence (every 6 weeks vs every 12 months) and ratings volume (779 vs 23). Knot Guide HD's advantage is in-app purchases (none vs 4) and price ($4.99 vs $9.99). On review sentiment and ads 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
PCalc costs $9.99 and Knot Guide HD $4.99 up front. PCalc sells 4 one-off in-app purchases. Knot Guide HD asks for nothing beyond the download.
PCalc holds the better App Store score, 4.7 against 4.1. That said, the two scores are not equally well evidenced: PCalc has 779 ratings behind it against 23, so its average is the more settled of the two. Written reviews point the same way: 83% of PCalc's written reviews are positive against 77% of Knot Guide HD's.
PCalc ships an update every 6 weeks, Knot Guide HD every 12 months. The most recent releases landed on November 10, 2026 and November 1, 2026 respectively.
| Parameter | PCalc | Knot Guide HD |
|---|---|---|
| Price | $9.99 | $4.99 — better |
| Rating | 4.7 (779 ratings) — better | 4.1 (23 ratings) |
| Positive reviews | 83.4% of reviews — better | 77.4% of reviews |
| Number of ratings | 779 — better | 23 |
| Update frequency | Every 6 weeks — better | Every 12 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Best chart rank | #94 — better | — |
| Devices | iPhone, iPad, iPod, Apple Watch, Vision Pro — better | iPad |
| Requires iOS | 15.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 83 MB | 99 MB |
| Age rating | 4+ | 4+ |
| Developer | TLA Systems Ltd. | Winkpass Creations, Inc. |
Customer experience
PCalc
Knot Guide HD
In-app purchases
PCalc
- Small Tip$0.99
- Medium Tip$1.99
- Large Tip$4.99
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- Enormous Tip$9.99
Knot Guide HD
No in-app purchases









