ArchMM vs Model Scale Calculator

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.

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.