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Miniature Scale Calculator — Model Size Converter for Any Scale

Convert real-world measurements to precise miniature dimensions for any hobby scale

Model Size

5-3/4"

Scale

1:12

Metric

146.0mm

Units

Model Size at 1:12

5-3/4"
5.750" decimal
Metric
14.6cm
Scale Factor
1:12
Dollhouse Standard

Scale Comparison (6' Person)

1:6 (Action Figure)11.50"
1:12 (Dollhouse)5.75"
1:64 (Hot Wheels)1.08"
1:87 (HO Train)0.79"
1:160 (N Gauge)0.43"

Height of a 5'9" person at each common scale

Common Objects at 1:12

ObjectRealModelmm
Interior Door6'8"6-11/16"169.3
Window (standard)4'0"4"101.6
Dining Table30"2-1/2"63.5
Chair Seat18"1-1/2"38.1
Person (avg)5'9"5-3/4"146.0
Bed (queen L)6'8"6-11/16"169.3

Scale Reference

Scale1 ft =Use
1:62"Action figures
1:121"Dollhouse std
1:241/2"Half-scale dollhouse
1:481/4"O gauge trains
1:643/16"Hot Wheels
1:873.5mmHO gauge trains
1:1601.9mmN gauge trains
1:2201.4mmZ gauge trains

Miniature Building Tips

Precision: Use digital calipers for scales smaller than 1:48. A 1/16" error at 1:87 equals 5.4" in real life.
Test Fit: Cut a test piece from scrap before committing to final materials. Verify against a known reference object at the same scale.
Scale Lumber: Basswood and balsa strips are available pre-cut in common miniature lumber sizes for 1:12, 1:24, and 1:48 scales.
Metric Advantage: For HO (1:87) and smaller scales, work in millimeters. Fractions of an inch become impractical below 1/16".

Example Calculations

11:12 Dollhouse — Standard Interior Door

Inputs

Scale1:12 (Dollhouse)
DirectionReal → Model
Real Height6 ft 8 in (80 in)

Result

Model Height6-11/16" (169.3mm)
Exact Decimal6.667"
Metric169.3mm

A standard 6'8" door at 1:12 scale becomes 80 ÷ 12 = 6.667 inches, which rounds to 6-11/16" for practical measurement. This is the most common dollhouse conversion.

21:87 HO Scale — 40-Foot Boxcar

Inputs

Scale1:87 (HO Train)
DirectionReal → Model
Real Length40 ft 0 in (480 in)

Result

Model Length5-1/2" (140.1mm)
Exact Decimal5.517"
Metric140.1mm

A 40-foot boxcar at HO scale (1:87) becomes 480 ÷ 87 = 5.517 inches, about 5-1/2 inches or 140mm. HO modelers typically work in millimeters for this precision level.

31:64 Hot Wheels — Room Mode (12×10×8 ft)

Inputs

Scale1:64 (Hot Wheels)
ModeRoom (L×W×H)
Room Size12 ft × 10 ft × 8 ft

Result

Model Room2.25" × 1.875" × 1.5"
Model Floor Area4.22 sq in
Model Volume6.33 cu in

A 12×10×8 ft room at 1:64 scale becomes 2.25" × 1.875" × 1.5". The floor area shrinks by 64² = 4,096× and volume by 64³ = 262,144×.

Frequently Asked Questions

Q

What does 1:12 scale mean for dollhouses?

In 1:12 scale, every 1 inch in the miniature equals 1 foot in real life. A 6-foot-8 door (80 inches tall) becomes 6.67 inches in the model. This is the most popular dollhouse scale because it produces miniatures large enough to show fine detail while staying compact enough to display.

  • 1 inch in model = 1 foot in real life — the simplest conversion ratio
  • Standard door (6'8"): 6.67" tall in 1:12 scale
  • Dining table (30" tall): 2.5" tall in 1:12 scale
  • Chair seat (18" high): 1.5" high in 1:12 scale
  • 1:12 accessories widely available at craft stores and online
Real ObjectReal Size1:12 Model Size
Interior Door6'8" × 2'8"6.67" × 2.67"
Dining Table30" tall2.5" tall
Chair18" seat height1.5" tall
Person5'9" (69")5.75"
Q

How do I convert real dimensions to model scale?

Divide the real-world measurement by the scale factor. For 1:87 HO scale, a 60-foot boxcar (720 inches) becomes 720 ÷ 87 = 8.28 inches. For area, divide by the factor squared. For volume, divide by the factor cubed. Always measure in the smallest practical unit first to avoid rounding errors.

  • Length formula: model size = real size ÷ scale factor
  • Area formula: model area = real area ÷ scale factor²
  • Volume formula: model volume = real volume ÷ scale factor³
  • Example: 10-foot wall at 1:87 = 120" ÷ 87 = 1.38" (35mm)
  • Reverse: model size × scale factor = real-world size
ScaleFactor6' Person HeightTypical Use
1:12126"Dollhouses
1:64641.13"Hot Wheels
1:87870.83" (21mm)HO trains
1:1601600.45" (11.4mm)N gauge
Q

What are the most common miniature scales?

1:12 is the standard for dollhouses, 1:64 for Hot Wheels and Matchbox, 1:87 for HO gauge model trains (the world's most popular train scale), and 1:160 for N gauge. Action figures use 1:6 (12-inch) or 1:18. Wargaming miniatures typically use 1:48 to 1:64.

  • 1:6 — 12-inch action figures (GI Joe, Barbie)
  • 1:12 — Dollhouse standard, largest common scale
  • 1:24 — Half-scale dollhouse and larger diecast cars
  • 1:64 — Hot Wheels, Matchbox, S gauge trains
  • 1:87 — HO gauge model trains, most popular worldwide
  • 1:160 — N gauge trains, popular for small layouts
ScaleName / Use1 Foot EqualsDetail Level
1:6Action Figures2"Very High
1:12Dollhouses1"High
1:87HO Trains3.5mmMedium
1:160N Gauge1.9mmLow
Q

How does area and volume scale differently from length?

Area scales as the square of the ratio and volume as the cube. At 1:12 scale, a 10×10 foot room floor (100 sq ft) becomes 100 ÷ 144 = 0.69 sq ft (100 sq in). Volume at 1:12 is divided by 1,728. This matters for filling miniature rooms with realistic proportions and ordering materials.

  • Length: divide by scale factor (1:12 → ÷12)
  • Area: divide by factor² (1:12 → ÷144)
  • Volume: divide by factor³ (1:12 → ÷1,728)
  • 10×10 ft room at 1:12: floor = 10" × 10" = 100 sq in
  • 1:87 HO scale: area shrinks by 7,569×, volume by 658,503×
DimensionFormula1:12 Factor1:87 Factor
Length÷ Scale÷ 12÷ 87
Area÷ Scale²÷ 144÷ 7,569
Volume÷ Scale³÷ 1,728÷ 658,503
Q

What tools do I need for accurate miniature measurements?

A digital caliper accurate to 0.01mm is essential for scales smaller than 1:48. For 1:12 dollhouse scale, a standard ruler with 1/16-inch markings works. Use a scale ruler (architect's rule) marked in your specific scale for faster measuring. A magnifier helps verify dimensions below 5mm.

  • Digital caliper (0.01mm): required for HO, N, and Z scale work
  • Metal ruler with 1/16" marks: adequate for 1:12 and 1:24 scale
  • Architect's scale ruler: pre-marked for 1:12, 1:24, 1:48 scales
  • Cutting mat with grid: helps align and measure flat pieces
  • Magnifier or loupe: verify sub-5mm dimensions on small scales
ToolPrecisionBest ForCost
Metal Ruler1/16"1:12, 1:24 scale$3–$8
Architect’s RulePre-marked scales1:12, 1:24, 1:48$8–$15
Digital Caliper0.01mmHO, N, Z scale$15–$30
Q

How do I display fractional inch results for miniatures?

Results under 1 inch are shown in common fractions: 1/16, 1/8, 3/16, 1/4, 5/16, 3/8, 7/16, 1/2, and so on. The calculator rounds to the nearest 1/16 inch for practical workshop use. For HO and smaller scales, millimeters are more practical since dimensions fall below 1/4 inch.

  • Fractions snap to nearest 1/16": standard for woodworking and crafts
  • 1/16" = 1.59mm — the practical limit for hand measurement
  • For HO scale (1:87) and smaller, use millimeters instead of fractions
  • Metric display always available alongside imperial fractions
  • Digital calipers read in both mm and inches for easy cross-reference
ScaleBest Unit1 Foot EqualsPrecision Needed
1:6Inches + fractions2"1/16"
1:12Inches + fractions1"1/16"
1:87 (HO)Millimeters3.5mm0.1mm
1:160 (N)Millimeters1.9mm0.05mm

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Last Updated: Mar 9, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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