Scales HD vs Scale Ratio
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- Architectural US Scales
- Engineering US Scales
- Metric SI Scales
- Tape Measure Tool
- Spirit Level Tool
- Flip Scales Option
- Music Control
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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.
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.
- Convert distances between any scales
- Supports architecture and modeling projects
- Instant calculation of scaled distances
- User-friendly input for distance and scale
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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
Verdict
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
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.
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.
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.
| Parameter | Scales HD | Scale Ratio |
|---|---|---|
| Price | $3.99 | Free — better |
| Rating | 4.2 (5 ratings) — better | 3.7 (3 ratings) |
| Positive reviews | 50.0% of reviews | 83.3% of reviews — better |
| Number of ratings | 5 — better | 3 |
| Update frequency | Every 95 months | Fortnightly — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | Free with in-app purchases — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.0 | 10.0 — better |
| Further details — not scored | ||
| Size | 7 MB | 25 MB |
| Age rating | 4+ | 4+ |
| Developer | Marcelo Mejia Cobo | Adrien Brecheteau |
Customer experience
Scales HD
Scale Ratio
In-app purchases
Scales HD
No in-app purchases
Scale Ratio
- Delete Ads in the app$4.99
Questions
Is Scales HD free?
Is Scale Ratio free?
Which has better reviews, Scales HD or Scale Ratio?
Do Scales HD or Scale Ratio have ads?
Which is updated more often, Scales HD or Scale Ratio?
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