Model Scale Calculator vs Scale Ruler

A scale converter for people who build models. Pick a scale — HO, N, O, 1:35 armour, 28mm heroic, 1/4" = 1' — type a dimension, and read the answer as you type. Free, offline, no account, no ads. THREE ANSWERS, ONE SCREEN • Real → model — how big is a 40-foot boxcar in HO? • Model → real — this part measures 92 mm; what is that full size? • What scale is this? — give a real length and the model length it has to come out at, and get the ratio. COMPARE ACROSS SCALES A second view takes one measurement and shows it in every scale in a hobby group at once — model railway gauges, military armour, aircraft, tabletop miniatures — with a proportional bar per row so you can judge the sizes by eye instead of reading numbers. UNITS HOBBYISTS ACTUALLY TYPE It parses what you would write on a workbench note: 250mm, 2.5 cm, 5' 6", 5ft 6in, 1 1/2", 3/4", 1-1/2". Feet-and-inches and fractional inches are first-class output formats, not an afterthought — fractions come back as fractions, rounded to the precision you choose. SCALES INCLUDED • Model railways — Z, N, TT, HO, OO, S, O, G and more • Military and armour — 1:16, 1:35, 1:48, 1:72 • Aircraft — 1:32, 1:48, 1:72, 1:144 • Cars — 1:18, 1:24, 1:43, 1:64 • Tabletop and wargaming — 15mm, 28mm heroic, 32mm, 54mm • Architecture — imperial drawing scales like 1/4" = 1' and metric 1:50, 1:100 • Any custom ratio you type WORKS COMPLETELY OFFLINE No account, no sign-in, no sync, no paywall and no advertising. Every calculation happens on your device, and nothing you type is ever sent anywhere. The only thing the app ever sends is anonymous usage data — which scales and modes get used — and you can switch that off in Settings. For model railroaders, scale modellers, miniature painters, RC builders, dollhouse makers, architects and anyone who has ever stood in a hobby shop doing long division on their phone.

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.