Tools
Converter
Calculator
Enter a value above to calculate.
| Scale | Ratio | 1 mm model = |
|---|---|---|
| Z | 1:220 | 220 mm |
| UK N | 1:148 | 148 mm |
| OO UK | 1:76.2 | 76.2 mm |
| HO | 1:87 | 87 mm |
| S | 1:64 | 64 mm |
| O | 1:48 | 48 mm |
| G | 1:24 | 24 mm |
| 1:5 | 1:5 | 5 mm |
| 1:10 | 1:10 | 10 mm |
| 1:20 | 1:20 | 20 mm |
| 1:50 | 1:50 | 50 mm |
| 1:100 | 1:100 | 100 mm |
| 1:200 | 1:200 | 200 mm |
| 1:500 | 1:500 | 500 mm |
| 1:1250 | 1:1250 | 1,250 mm |
Reference tables
1 metre real → model (mm)
| Z | 4.55 mm |
| UK N | 6.76 mm |
| OO | 13.12 mm |
| HO | 11.49 mm |
| S | 15.63 mm |
| O | 20.83 mm |
| G | 41.67 mm |
1 foot real → model (inches)
| Z | 0.055 in |
| UK N | 0.082 in |
| OO | 0.157 in |
| HO | 0.138 in |
| S | 0.188 in |
| O | 0.250 in |
| G | 0.500 in |
How big is a 20m railway carriage at each scale?
Based on a standard 20m passenger coach. Click any row to select that scale in the calculator above.
What kind of model are you building?
Click a card to select that scale. What to buy and what to build at each architectural scale — from close-up detail to whole-city context.
Swipe to see all scales. Detail increases left to right — 1:5 is very close-up, 1:1250 is very abstract.
New tool
Scale Materials Advisor
Know your scale? Find the exact Evergreen or K&S profile to model a downpipe, timber section, steel beam or more — with fit judgement and price.
Metric to Imperial Converter
Enter a value to convert.
Accepts fractions — e.g. 1/32 3/16 1 3/8
1 inch = 25.4 mm exactly · Amber rows are common fractions.
Reference table
| Inches | Fraction | mm |
|---|---|---|
Standard Wire Gauge (SWG)
SWG (British Standard) is used for metal sheet, rod and wire in UK modelling. Higher numbers are thinner. K&S metals and most UK brass/aluminium tube is sold by SWG.
| SWG | Inches | mm |
|---|---|---|
| No matching gauges found. | ||
SWG 0–25 shown.