ArchMM vs Scale Ruler
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ArchMM
This app provides specialized calculation tools for architectural scales, model making, and carpentry. It handles measurements in feet, inches, and fractions, converting them for various design and building projects. Features include board feet calculation, stair layout assistance, and rafter geometry.
- Architectural scale conversions
- Model scale to millimeters
- Carpenter calculator with dedicated buttons
- Board feet calculation
- Stair layout and rafter geometry tools
- Copy results and multiple appearance themes
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Scale, measure, and calculate with ArchMM. A practical calculator for designers, model makers, builders, architects, and students—built around feet, inches, fractions, and architectural scale. MODEL SCALE Convert full-size feet and inches to model millimeters for 3D printing and model making, or work backward from a model measurement. Choose 1:1 or common architectural scales and compare the converted length with a printer-bed preset. CARPENTER CALCULATOR Use dedicated number, unit, fraction, and arithmetic buttons. Add and subtract dimensions, multiply lengths into area or volume, recall memory, and revisit recent calculations. The next number after equals starts a new calculation. SCALE TO INCHES Enter a full-size measurement and get its scaled size in inches. Change the drawing scale at any time. PROJECT TOOLS Calculate board feet, explore a stair layout, and work out common-rafter geometry. Each tool explains its assumptions. These are geometry estimates, not structural design or code-compliance approval. MADE FOR EVERYDAY WORK • Copy results for your next task • Light, Dark, and System appearance • On-device calculations with no account, ads, analytics, or tracking • No internet connection needed for calculations Printer checks compare one converted length with the bed dimensions. Confirm the complete part geometry, orientation, and clearances in your slicer.
Scale Ruler
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Scale Ruler brings a realistic triangular scale to your iPhone, designed for drafting, measuring, studying, and everyday reference. Explore multiple scale standards with a smooth, swipeable ruler interface that recreates the familiar look and feel of a physical triangular scale. KEY FEATURES • Realistic Triangular Scale View all three scale faces and swipe smoothly through detailed graduations. • Multiple Scale Standards Choose from commonly used standards for China, Japan, the United States, the United Kingdom, Germany, and more. • Custom Scale Ratios Create your own scale setup by adjusting ratios and graduations for individual ruler faces. • Labels & Markers Add custom labels and markers directly to the ruler for scale notes, project names, dates, and other references. • Automatic & Manual Calibration The app can calibrate based on your device display, with manual fine-tuning available using a physical ruler when greater precision is required. • Night Mode Use a darker interface for more comfortable viewing in low-light environments. Whether you're an architect, designer, engineer, student, model maker, or simply need a convenient scale reference, Scale Ruler puts a versatile triangular scale right on your iPhone. Some advanced customization features may require an in-app purchase.
Screenshots
Verdict
The clearest difference is in-app purchases: ArchMM at none against Scale Ruler's 1. On price, update cadence, 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
Both are free to download. Scale Ruler sells 1 one-off in-app purchase. ArchMM asks for nothing beyond the download.
ArchMM ships an update monthly, Scale Ruler every 2 weeks. The most recent releases landed on October 31, 2026 and November 6, 2026 respectively.
| Parameter | ArchMM | Scale Ruler |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (1 ratings) — better | — |
| Number of ratings | 1 — better | — |
| Update frequency | Monthly | Every 2 weeks — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Free | — |
| Devices | iPhone, Mac | iPhone, iPad, Apple Watch — better |
| Requires iOS | 18.0 | 17.0 — better |
| Further details — not scored | ||
| Size | 6 MB | 11 MB |
| Age rating | 4+ | 4+ |
| Developer | Brandon Davis | 佳 赵 |
In-app purchases
ArchMM
No in-app purchases
Scale Ruler
- Scale Ruler Pro$1.99








