ArchMM vs Model Scale Calculator

Architectural scale, without the guesswork. ArchMM is a focused iPhone utility for scenic designers, model makers, architects, students, and anyone moving between real-world dimensions and physical scale models. Choose a conversion direction, enter the measurement you already know, select the drawing scale, and get a result ready to use in your drafting, model-making, or 3D-printing workflow. FEATURES • Convert full-size feet and inches to model millimeters • Reverse model millimeters to full-size feet and inches • Work at 1:1 or use standard architectural scales from 1″ through 1/16″ • Compare converted lengths with common 3D-printer bed dimensions • Copy results with one tap • Keep your selected scale and printer ready for the next calculation • Work offline with no account, advertising, analytics, or tracking ArchMM keeps the calculation close, clear, and out of the way—so you can return to the drawing, model, or printer setup in front of you.

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.