Conversion Tables

Here you'll find various conversion tables to help you with your model-making projects, ensuring precision whether you're working with imperial or metric measurements, or understanding the various scales used across different modelling disciplines.

Table of Contents

Imperial to Metric Length Conversion

Inches
⟷
Millimetres

This table provides common fractional and decimal inch measurements with their millimetre equivalents. This is particularly useful for general measurements, including understanding common drill bit sizes, to assist with precise work in your projects.

Inches (Fraction) Inches (Decimal) Millimetres (mm)
0.010 0.25
1/64 0.016 0.40
0.020 0.51
0.030 0.76
1/32 0.031 0.79
0.040 1.02
3/64 0.047 1.19
0.050 1.27
0.060 1.52
1/16 0.063 1.59
0.070 1.78
5/64 0.078 1.98
0.080 2.03
0.090 2.29
3/32 0.094 2.39
0.100 2.54
7/64 0.109 2.78
1/8 0.125 3.18
9/64 0.141 3.57
5/32 0.156 3.96
11/64 0.172 4.37
3/16 0.188 4.76
13/64 0.203 5.16
7/32 0.219 5.56
15/64 0.234 5.95
1/4 0.250 6.35
5/16 0.313 7.94
3/8 0.375 9.53
7/16 0.438 11.11
1/2 0.500 12.70
9/16 0.563 14.29
5/8 0.625 15.88
11/16 0.688 17.46
3/4 0.750 19.05
13/16 0.813 20.64
7/8 0.875 22.23
15/16 0.938 23.81
1 1.000 25.40
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Railway Model Scales

This table will help you understand the common railway scales and their typical ratios and track gauges.

Scale Name Typical Ratio Track Gauge (Actual, Standard Gauge Prototype)
Z Scale 1:220 6.5 mm / 0.256 in
N Scale 1:160 9 mm / 0.354 in
HO Scale 1:87 16.5 mm / 0.650 in
OO Scale (UK) 1:76 16.5 mm / 0.650 in
S Scale 1:64 22.42 mm / 0.883 in
O Scale 1:48 (US), 1:43.5 (UK/Europe) 32 mm / 1.26 in
G Scale Various (e.g., 1:22.5, 1:29) 45 mm / 1.77 in
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Other Common Modelling Scales

Beyond architectural and railway modelling, a variety of scales are popular for doll's houses, miniature figures, vehicles, and general scratch-building projects. This table highlights some of the most frequently used scales in these areas, along with a typical real-world equivalent to help you visualise their size.

Scale (Ratio) Description / Common Use Real World Equivalent (e.g., 6 ft person)
1:12 The most popular scale for traditional Doll's Houses and realistic miniatures. Also used for some large-scale figures and vehicles. 183 cm (6 ft) person = 15.2 cm (6 in)
1:16 Popular for farm vehicles, some military models, and smaller-scale doll's houses. 183 cm (6 ft) person = 11.4 cm (4.5 in)
1:24 Common for model cars, aircraft, and some doll's house scales (often called 'Half Scale' to 1:12). 183 cm (6 ft) person = 7.6 cm (3 in)
1:32 Often used for toy soldiers, slot cars, and some aircraft models (known as 'Gauge 1' in railways). 183 cm (6 ft) person = 5.7 cm (2.25 in)
1:35 The dominant scale for military vehicles and figures (tanks, armoured cars). 183 cm (6 ft) person = 5.2 cm (2.06 in)
1:72 A very popular scale for aircraft, military vehicles, and figures, offering a good balance of detail and size. 183 cm (6 ft) person = 2.5 cm (1 in)
1:144 Common for aircraft (especially large airliners) and some science fiction models, offering compact size. 183 cm (6 ft) person = 1.27 cm (0.5 in)
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Wire Gauge Conversion Table

Understanding wire gauges is crucial for precise work across many model-making disciplines, from electrical wiring to creating intricate structural details. This table shows common AWG (American Wire Gauge) and SWG (Standard Wire Gauge - British) sizes, along with their approximate diameters in inches and millimetres.

AWG Gauge SWG Gauge Diameter (Inches) Diameter (mm)
10 13 0.102 2.59
12 15 0.081 2.05
14 16 0.064 1.63
16 18 0.051 1.29
18 20 0.040 1.02
20 22 0.032 0.81
22 24 0.025 0.64
24 26 0.020 0.51
26 28 0.016 0.41
28 30 0.013 0.32
30 32 0.010 0.25
32 34 0.008 0.20
34 36 0.006 0.16
36 38 0.005 0.13
38 40 0.004 0.10
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Metal Sheet Gauge Conversion

This table shows common metal sheet gauges and their thicknesses, particularly useful for brass and copper sheet work in model making.

Gauge Number Thickness (Inches) Thickness (mm) Common Uses
10 0.135 3.43 Heavy structural work, thick brackets
12 0.109 2.77 Medium structural components
14 0.083 2.11 General fabrication, panels
16 0.065 1.65 Light structural, detailed work
18 0.051 1.29 Model panels, light brackets
20 0.036 0.91 Fine detail work, thin panels
22 0.030 0.76 Precision work, small components
24 0.025 0.64 Very fine work, shims
26 0.018 0.46 Ultra-fine details, foil work
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A-Series Paper Sizes

ISO A-series paper sizes follow a mathematical relationship where each size is exactly half the area of the previous size.

Paper Size Dimensions (mm) Dimensions (inches) A4 Ratio Common Uses
A0 841 × 1189 33.1 × 46.8 A4 × 16 Large architectural drawings, posters
A1 594 × 841 23.4 × 33.1 A4 × 8 Technical drawings, large plans
A2 420 × 594 16.5 × 23.4 A4 × 4 Medium drawings, diagrams
A3 297 × 420 11.7 × 16.5 A4 × 2 Plans, templates, presentations
A4 210 × 297 8.3 × 11.7 A4 × 1 Standard documents, instructions
A5 148 × 210 5.8 × 8.3 A4 ÷ 2 Small notebooks, booklets
A6 105 × 148 4.1 × 5.8 A4 ÷ 4 Postcards, small templates
A7 74 × 105 2.9 × 4.1 A4 ÷ 8 Small flyers, tickets, labels
A8 52 × 74 2.0 × 2.9 A4 ÷ 16 Business cards, small stickers
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Material Density Reference

Understanding material densities helps calculate weights and structural properties for your model-making projects.

Material Density (g/cm³) Density (lb/in³) Notes
Brass 8.5 0.31 Alloy composition affects density
Copper 8.96 0.32 Pure copper
Carbon Fiber 1.6 0.058 Varies with weave and resin
Balsa Wood 0.16 0.0058 Very lightweight, varies widely
Pine Wood 0.52 0.019 Softwood, common for frameworks
Oak Wood 0.75 0.027 Hardwood, very durable
Foam Board 0.05 0.0018 Polystyrene foam core
Polymer Clay 1.7 0.061 After baking
Cardboard 0.7 0.025 Varies with thickness and type
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Temperature Conversion

Essential for clay work, adhesive curing, and metalworking temperatures.

Celsius (°C) Fahrenheit (°F) Common Application
110 230 Polymer clay baking (Sculpey)
130 266 Fimo clay baking
180 356 Heat gun setting (low)
200 392 Epoxy curing acceleration
250 482 Soldering temperature (low)
350 662 Lead-free solder melting
600 1112 Heat treatment (annealing)
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Sandpaper Grit Sizes

This table explains common sandpaper grit sizes and their uses, which is very relevant for model making.

Grit Number Description Common Use in Model Making
40-60 Very Coarse Heavy material removal, rough shaping, removing large imperfections (rarely for fine models).
80-120 Coarse to Medium Initial shaping, removing saw marks, preparing for finer grits.
150-180 Medium to Fine General sanding, smoothing surfaces, removing light scratches.
220-320 Fine Final sanding before priming/painting, light denibbing.
360-600 Very Fine Wet sanding for very smooth finishes, preparing for high-gloss paints.
800-1500 Super Fine Polishing, removing minor imperfections in clear coats, preparing for compounds.
2000+ Ultra Fine Mirror finishing, headlight restoration, ultimate clear coat polishing.
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Weight Conversion Table

This chart helps you convert between common weight measurements, useful for material calculations or balancing models.

Grams (g) Ounces (oz) Pounds (lb)
1 0.035 0.0022
10 0.353 0.0220
25 0.882 0.0551
50 1.764 0.1102
100 3.527 0.2205
250 8.818 0.5512
500 17.637 1.1023
1000 35.274 2.2046
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Volume Conversion Table

Useful for mixing adhesives, resins, and paints in small quantities.

Millilitres (ml) Fluid Ounces (fl oz) Cubic Inches (in³) Common Use
1 0.034 0.061 Small detail work
5 0.169 0.305 Small adhesive mixtures
15 0.507 0.915 Tablespoon measurement
30 1.014 1.831 Standard fluid ounce
60 2.029 3.661 Small paint mixtures
100 3.381 6.102 Medium batches
250 8.454 15.260 Cup measurement
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Angle Conversion

Useful for cutting compound angles and understanding geometric relationships in model making.

Degrees (°) Radians Common Application
15° 0.262 Fine detail angles
22.5° 0.393 Octagon construction
30° 0.524 Common cutting angle
45° 0.785 Mitre cuts, corner joints
60° 1.047 Hexagon construction
90° 1.571 Right angles, perpendicular cuts
120° 2.094 Obtuse angles
180° 3.142 Straight line, flat angle