Scale Calculator for Models and Architecture

Enter a full-size span, choose from 36 scale ratios, then copy scaled millimetres and companion units.

Insert a real-world value

Unit

Decimal in the unit you selected, or feet and inches (for example 6'2" or 6 ft 2 in). When you use feet and inches, that value is used even if another unit is selected.

Select your scale

Selected: 1:87.1 (HO)

Filter scales

Model railway

Automotive

Aircraft

Military

Naval

Architecture

Figures

Dollhouse

Scaled result

11.481 mm

1.148 cm · 0.011 m · 0.452 in · 0.038 ft

Reference object comparison

Scaled length at 1:87.1; millimetres listed first for kit and bench work. In the workbench below, the high-contrast bar is your scaled length; lighter shapes are reference-only silhouettes.

Browse standard objects

Quick-load catalog

Pick a reference length; values load into the engine in millimeters.

Scales available in this calculator

Fixed ratios you can select above. Each run uses one scale; model length is real-world length divided by the denominator.

Scale	Common name	Used for
1:6 / 1/6	—	Automotive, Figures, Dollhouse
1:9 / 1/9	—	Automotive
1:12 / 1/12	—	Automotive, Figures, Dollhouse
1:16 / 1/16	—	Automotive, Military
1:18 / 1/18	—	Automotive
1:20 / 1/20	—	Automotive, Architecture
1:22.5 / 1/22.5	G	Model railway
1:24 / 1/24	—	Automotive, Dollhouse
1:25 / 1/25	—	Automotive
1:29 / 1/29	G	Model railway
1:32 / 1/32	Gauge 1	Model railway, Automotive, Aircraft, Military
1:35 / 1/35	—	Military
1:43 / 1/43	—	Automotive
1:43.5 / 1/43.5	British O	Model railway
1:45 / 1/45	European O	Model railway
1:48 / 1/48	O	Model railway, Aircraft, Military, Architecture, Dollhouse
1:50 / 1/50	—	Architecture
1:60 / 1/60	—	Figures
1:64 / 1/64	S	Model railway, Automotive
1:72 / 1/72	—	Aircraft, Military
1:76.2 / 1/76.2	OO	Model railway, Military
1:87.1 / 1/87.1	HO	Model railway
1:96 / 1/96	—	Naval, Architecture
1:100 / 1/100	—	Aircraft, Architecture, Figures
1:120 / 1/120	TT	Model railway
1:144 / 1/144	—	Aircraft, Figures
1:148 / 1/148	British N	Model railway
1:150 / 1/150	Japanese N	Model railway
1:160 / 1/160	N	Model railway
1:200 / 1/200	—	Aircraft, Naval, Architecture
1:220 / 1/220	Z	Model railway
1:350 / 1/350	—	Naval
1:400 / 1/400	—	Aircraft, Naval
1:500 / 1/500	—	Architecture
1:700 / 1/700	—	Naval
1:1200 / 1/1200	—	Naval

Source measurement