Comparison

HVAC Pipe Sizer vs Graph Paper

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

Head to head
About

HVAC Pipe Sizer

Calculate gas piping systems for low and high pressure. Input flow, pressure, or diameter to find pipe sizes, velocity, and equivalent lengths. Supports English and metric units, with extensive pipe fitting data.

Highlights
  • Low and high pressure gas pipe sizing
  • Calculate flow, pressure drop, diameter, and velocity
  • Universal app for iPhone and iPad
  • English and metric unit support
  • Built-in pipe fitting equivalent length tables
  • Slider controls for quick adjustments
Features
Read full description

The "HVAC Pipe Sizer - Gas Plus" application allows you to quickly size a simple low (less than or equal to 1.5 psi) and/or high (greater than 1.5 psi) pressure gas piping system by inputting a number of piping and gas properties. This application combines the functionality of our popular "HVAC Pipe Sizer - Gas Low" and "HVAC Pipe Sizer - Gas High" applications. This app is now a universal app meaning that it works on both the iPhone and iPad and adjusts its screen size accordingly. For low pressure gas piping, you can specify the total gas flow in ft3/hr (m3/hr) and one of either pressure drop (in. wg or Pa), pipe internal diameter (inches) or gas velocity (ft/s) parameters. The results include both the exact and nominal pipe diameters and the calculated velocity and total pipe equivalent length. If you are analyzing an existing pipe system, there is an option to input the existing pipe internal diameter and one of either pressure drop or gas velocity parameters to derive the calculated gas flow and other remaining properties. For high pressure gas piping, you can specify the total gas flow in ft3/hr (m3/hr), the upstream pressure (psig or kPa), and one of either downstream pressure (psig or kPa), pipe internal diameter (inches) or gas velocity (ft/s) parameters. The results include both the exact and nominal pipe diameters and the calculated velocity and total pipe equivalent length. If you are analyzing an existing pipe system, there is an option to input the existing pipe internal diameter, the upstream pressure, and one of either downstream pressure or gas velocity parameters to derive the calculated gas flow and other remaining properties. You can specify additional parameters such as the type of gas, various properties of the gas, the pipe material type, the total length of pipe, quantities for up to 11 different types of pipe fittings, and much more. You can also choose to display values in either english or metric units. This application includes built-in pipe fitting equivalent length and nominal pipe sizing tables for a wide variety of pipe material types and diameters. This application uses slider controls that allow you to quickly increment or decrement the input values and immediately observe the calculated results. You can also manually input exact values. This app now includes the HVAC Equipment Locator. Click here for details: http://bit.ly/1yTq539 The "HVAC Pipe Sizer - Gas Plus" application was designed by Carmel Software Corporation, a leader in HVAC design software since 1995. In fact, Autodesk (the makers of AutoCAD) acquired our load calculation software and incorporated it into their leading 3D modeling software called Revit. In addition, we developed a number of customized apps for ASHRAE, DNV GL, and other organizations. We also offer the following additional apps for the iPhone and iPad: 1. HVAC Residential Load Calcs for iPhone and iPad 2. HVAC Quick Load Plus 3. HVAC Quick Load 4. HVAC Toolkit 5. HVAC Pipe Sizer – Gas Low Pressure 6. HVAC Pipe Sizer - Gas High Pressure 7. HVAC Pipe Sizer – Liquid 8. HVAC Pipe Sizer – Steam 9. Steam Tables 10. Psychrometric Plus 11. Psychrometric LT 12. HVAC Pipe Sizer Plus 13. HVAC Pipe Sizer Gas Plus 14. HVAC Toolkit Ultimate 15. HVAC Equipment Locator 16. HVAC ResLoad-J 17. HVAC Psych HD

About

Graph Paper

This app allows users to create digital graph paper for various purposes, from mapping game worlds to designing crafts. It offers drawing tools, text options, and different paper styles, with saving and export capabilities.

Highlights
  • Line weight and multiple colors
  • Square and circle shapes
  • Add text with various fonts
  • Resizable and isometric grids
  • Save, export to PDF, and print
  • Line snap and ortho modes
Features
Read full description

Graph Paper is a simple app to replicate real-life graph paper. I tried to make Graph Paper simple to use without creating too much complication that you might find in other CAD applications. You can use it map out Minecraft locations, graph coordinates in your math or engineering class, or draw out cross-stitch patterns. The possibilities are endless. Feature highlights: Drawing and Designing - Line weight - Multiple colors (More can be purchased in app) - Line Types ( Solid, Dashed, Dots ) - Square and Circle Shapes - Line Snap and Ortho - Coordinate tool tips Text - Add text to your drawing - Select from different fonts, sizes and colors Paper Types - Resizable Grid. - Isometric Paper Grid - Blueprint paper Saving and Exporting - Save drawings and come back to them later. - Save to Camera Roll as Picture - Email as PDF - Print from inside Graph Paper Help documentation included to show you how to use features.

Screenshots

HVAC Pipe Sizer4 screens

Verdict

The call

The clearest difference is review sentiment: HVAC Pipe Sizer at 80% against Graph Paper's 25%. HVAC Pipe Sizer also leads on rating (5.0 vs 1.0) and device support (3 vs 1). Graph Paper's advantage is update cadence (every 5 weeks vs every 12 months) and price ($3.99 vs $7.99). On ads and in-app purchases 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

HVAC Pipe Sizer costs $7.99 and Graph Paper $3.99 up front. HVAC Pipe Sizer sells 1 one-off in-app purchase and Graph Paper sells 8 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

HVAC Pipe Sizer holds the better App Store score, 5.0 against 1.0. That said, the two scores are not equally well evidenced: Graph Paper has 8 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 80% of HVAC Pipe Sizer's written reviews are positive against 25% of Graph Paper's.

UpkeepUpdate frequency

HVAC Pipe Sizer ships an update every 12 months, Graph Paper every 5 weeks. The most recent releases landed on September 26, 2026 and October 13, 2026 respectively.

Scorecard8 real differences · 2 level
HVAC Pipe Sizer versus Graph Paper: the parameters behind the verdict, then further details
ParameterHVAC Pipe SizerGraph Paper
Price$7.99$3.99 — better
Rating5.0 (1 ratings) — better1.0 (8 ratings)
Positive reviews80.0% of reviews — better24.5% of reviews
Number of ratings18 — better
Update frequencyEvery 12 monthsEvery 5 weeks — better
AdsNoNo
In-app purchasesYesYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPad, iPod — betteriPad
Requires iOS15.69.1 — better
Further details — not scored
Size18 MB6 MB
Age rating4+4+
DeveloperCarmel Software CorporationAdam McElhaney

Customer experience

HVAC Pipe Sizer

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews5 reviews
Positive80.0%
Neutral0.0%
Negative20.0%

Graph Paper

All ratings8 ratings
Positive0.0%
Neutral0.0%
Negative100.0%
Written reviews102 reviews
Positive24.5%
Neutral17.6%
Negative57.8%

Bugs and requests

HVAC Pipe Sizer

Not enough reviews yet to summarise bugs or requests.

Graph Paper

Reported bugs

20 issues
  • App crashes when opening saved documents
  • App crashes when zoomed in
  • App crashes when adding text
  • App crashes when using measurement/distance tool
  • App crashes when drawing lines while zoomed
Show 15 more
  • App crashes when inserting words into drawings
  • Saved files become corrupted or inaccessible
  • Grid snap works horizontally but not vertically
  • Unintended 'ghost lines' appear when tapping screen
  • Undo button is difficult to target and triggers drawing instead
  • Redo button does not function
  • Text appears tiny and distorted
  • Saved files don't reopen properly
  • Drawing appears off-grid after reopening
  • Printing cuts off image or prints off-center
  • Grid lines don't print with image
  • Multi-touch causes crosshairs to freeze
  • Recent updates broke existing functionality
  • Performance issues with slow/laggy drawing
  • Unwanted recurring charges reported

Requested features

21 requests
  • Eraser tool for selective line deletion
  • Zoom in/out capability
  • Pan/scroll functionality for larger canvases
  • Freehand drawing mode
  • Ability to move and edit objects after placement
Show 16 more
  • Fill/color bucket tool for squares and shapes
  • Curved lines and diagonal lines
  • Text editing and deletion capabilities
  • Landscape mode orientation
  • Larger default grid squares
  • More color options (orange, purple, green)
  • Ability to duplicate elements
  • Dimension input by keyboard
  • More measurement units (feet, not just inches)
  • Ability to save designs as reusable templates
  • Arrows and curved line tools
  • Greek letters and equation support
  • Rotation tool for objects
  • Improved printing with proper centering
  • Better Apple Pencil support
  • Larger toolbar buttons for easier selection

In-app purchases

1 purchases

HVAC Pipe Sizer

One-time1
  • HVAC Equipment Locator$9.99
8 purchases

Graph Paper

One-time8
  • Color Pack - Khaki$0.99
  • Color Pack - Gold$0.99
  • Color Pack - Orange$0.99
Show 5 more
  • Color Pack - Green$0.99
  • Color Pack - More Blue$0.99
  • Color Pack - Purples$0.99
  • Color Pack - Pinks$0.99
  • Color Pack - Yellow$0.99

Questions

Is HVAC Pipe Sizer free?
HVAC Pipe Sizer costs $7.99, and also offers in-app purchases.
Is Graph Paper free?
Graph Paper costs $3.99, and also offers in-app purchases.
Which has better reviews, HVAC Pipe Sizer or Graph Paper?
HVAC Pipe Sizer is rated higher. HVAC Pipe Sizer averages 5.0 out of 5 from 1 ratings, while Graph Paper averages 1.0 from 8 ratings.
Do HVAC Pipe Sizer or Graph Paper have ads?
Neither HVAC Pipe Sizer nor Graph Paper shows ads.
Which is updated more often, HVAC Pipe Sizer or Graph Paper?
HVAC Pipe Sizer ships an update every 12 months, and Graph Paper every 5 weeks. Most recently, HVAC Pipe Sizer was updated on September 26, 2026 and Graph Paper on October 13, 2026.

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