Comparison

Scales HD vs Scale Ratio

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

Head to head
About

Scales HD

This app provides a digital architectural and engineering scale ruler with various US and Metric scales. It includes tools like a tape measure and spirit level, with options to flip scales and lock scrolling. Control your music library directly from the app.

Highlights
  • Architectural US Scales
  • Engineering US Scales
  • Metric SI Scales
  • Tape Measure Tool
  • Spirit Level Tool
  • Flip Scales Option
  • Music Control
Features
Read full description

Scales HD puts a real architect's and engineer's scale rule in your pocket, drawn at true physical size on every iPhone and iPad, so a millimetre on screen is a millimetre on your drawing. Around it: a CAD, Room Scan, a PDF blueprint reader, a construction calculator, notes and more. TRUE SIZE ON EVERY DEVICE • Exact screen density for every iPhone, iPad and iPhone Duo model • Zero at the screen edge or the device edge; optional calibration TRIANGULAR SCALES, JUST LIKE THE REAL ONE • Turn the scale to its other sides; all four edges on each, the original artwork's grooves and faces • One tap prints the US ↔ metric equivalent beside every scale: 1:48 next to 1/4" = 1'-0" • Two measuring lines read in both edge scales at once, with snapping EVERY SCALE YOU USE • US architectural 1/32" to 12" = 1'-0"; engineering 1" = 10' to 120' • Metric 1:1 to 1:10000, civil and survey; mechanical; UK and Japanese rules • Enlargements, maps 1:24000 to 1:250000, model rail and kits; read any edge at ×10 or ×100 • Your own scales, any ratio, in your own color CAD • Walls, doors, windows, furniture and dimensions at real size; freehand too • Booleans, trim, extend, fillet, offset, arrays, layers, edit in place • About 700 templates: full project sets, homes, interiors, ADA, landscape, sections, details, MEP • Export true-scale PDF or SVG, PNG, DXF and DWG; open DWG and DXF drawings ROOM SCAN (LiDAR iPhone and iPad) • Scan rooms into floor plans, elevations, a room schedule and 3D models • Stitch rooms, set a measured length, export USDZ, OBJ, glTF, IFC and DXF, or open as a CAD drawing BLUEPRINTS • PDF drawing sets as sheets you can search and bookmark • Set the sheet's scale and measure lengths, areas and counts; mark up with clouds, callouts and stamps • Compare revisions; stand a plan in the room at 1:1 in AR CONSTRUCTION CALCULATOR • Feet-inch-fraction and metric, mixed freely: 5'-3 1/2" + 80 cm • Areas, volumes, diagonal, pitch, stairs, circles; a tape of your calculations NOTES THAT SKETCH • Lists, checklists and a full row of symbols, fractions and units over the keyboard • Drop in pictures, PDF pages and CAD drawings, then move and size them; text flows around • Quick sketch stickies: draw with a finger or Apple Pencil in any color and pen VOICE • A microphone on every screen: "use 1 to 50", "3 feet 4 inches plus 2 feet", "place a queen bed against the north wall". Understood on the device MORE TOOLS • Unit converter: 11 families, 94 units • Scale converter: drawing ↔ real size, redraw at another scale, find a drawing's scale • Protractor: read an angle on paper at true size, between two surfaces by tilt, or on the iPhone Duo's hinge, with the supplement, the miter and the saw setting • Spirit level with the original bubble, compass, tape, cutting board, haptics MADE FOR iPHONE DUO • Closed, every tool fits the outer screen around the camera; open, the big screen; half open, the calculator, level, compass, protractor and blueprints keep off the fold; the hinge itself is a protractor iPhone and iPad, iCloud sync between your devices. No ads, no tracking, no account, no subscription.

About

Scale Ratio

Easily convert distances between any scales for projects like architecture and model building. Input your measurements and desired scale to instantly calculate scaled distances.

Highlights
  • Convert distances between any scales
  • Supports architecture and modeling projects
  • Instant calculation of scaled distances
  • User-friendly input for distance and scale
Features
Read full description

Scale a measurement to a larger or smaller measurement, which is useful for architecture, modelling, and other projects. This app can be used to easily convert any distance in any scale to any other distance in any other scale. Simply enter the distance and scale to convert and the result will be displayed instantly. You need for example to create a mock up of a building at the scale 1:500. Enter the ground distances in the calculator, set the scale ratio to 1:500 and you'll get the mock up distance.

Screenshots

Scales HD4 screens
Scale Ratio3 screens

Verdict

The call

The clearest difference is price: Scale Ratio at Free against Scales HD's $3.99. Scale Ratio also leads on review sentiment (83% vs 50%) and update cadence (fortnightly vs every 95 months). Scales HD's advantage is rating (4.2 vs 3.7) and in-app purchases (none vs 1). On ratings volume, ads and device support 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

Scale Ratio is free to download; Scales HD costs $3.99 up front. Scale Ratio sells 1 one-off in-app purchase. Scales HD asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Scales HD holds the better App Store score, 4.2 against 3.7. Both are backed by a comparable volume of ratings — 5 and 3 respectively. Written reviews complicate that: 50% of Scales HD's written reviews are positive against 83% of Scale Ratio's, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

Scales HD ships an update every 95 months, Scale Ratio fortnightly. The most recent releases landed on November 1, 2026 and November 2, 2026 respectively.

Scorecard7 real differences · 3 level
Scales HD versus Scale Ratio: the parameters behind the verdict, then further details
ParameterScales HDScale Ratio
Price$3.99Free — better
Rating4.2 (5 ratings) — better3.7 (3 ratings)
Positive reviews50.0% of reviews83.3% of reviews — better
Number of ratings5 — better3
Update frequencyEvery 95 monthsFortnightly — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationPaidFree with in-app purchases — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS15.010.0 — better
Further details — not scored
Size7 MB25 MB
Age rating4+4+
DeveloperMarcelo Mejia CoboAdrien Brecheteau

Customer experience

Scales HD

All ratings4 ratings
Positive75.0%
Neutral0.0%
Negative25.0%
Written reviews4 reviews
Positive50.0%
Neutral25.0%
Negative25.0%

Scale Ratio

All ratings3 ratings
Positive66.7%
Neutral0.0%
Negative33.3%
Written reviews6 reviews
Positive83.3%
Neutral0.0%
Negative16.7%

In-app purchases

None

Scales HD

No in-app purchases

1 purchases

Scale Ratio

One-time1
  • Delete Ads in the app$4.99

Questions

Is Scales HD free?
Scales HD costs $3.99, with no in-app purchases.
Is Scale Ratio free?
Scale Ratio is free to download, with in-app purchases available.
Which has better reviews, Scales HD or Scale Ratio?
Scales HD is rated higher. Scales HD averages 4.2 out of 5 from 5 ratings, while Scale Ratio averages 3.7 from 3 ratings.
Do Scales HD or Scale Ratio have ads?
Neither Scales HD nor Scale Ratio shows ads.
Which is updated more often, Scales HD or Scale Ratio?
Scales HD ships an update every 95 months, and Scale Ratio fortnightly. Most recently, Scales HD was updated on November 1, 2026 and Scale Ratio on November 2, 2026.

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