A scale model converter and conversion workbench for hobbyists: real↔model math, hobby scale presets (HO, N, O, 1:72, 1:48, 1:35, ships, dollhouse, Gundam, wargaming), a what-scale detective, between-scale rescale %, printable scale rulers, scale speeds, size comparisons and paint mixing — all in one page.
This scale model conversion calculator converts any real-world dimension to model size — or measures your model to recover the real size. This model size converter doubles as a model railroad scale converter, HO scale converter and dollhouse scale calculator: pick a hobby preset or type any custom ratio. Results include inches to mm conversion and fractional-inch output for your ruler.
Measure one feature on the model and enter its known real-world size — a door (≈6 ft 8 in), a railcar, a human figure (≈5 ft 9 in). The lab matches your ratio against 25 standard hobby scales.
Have a plan, decal or 3D print in one scale and need to convert scale to another scale? Get the exact print/enlarge percentage — the question forums answer by hand every week.
Generate a ruler graduated in scale feet (imperial) or scale meters (metric) for your exact scale. Print it, lay it on your plan, and read real-world sizes directly.
This model train scale speed calculator converts a timed run into scale miles per hour (smph) — how fast your train would be going full-size — or turns a prototypical speed into the matching model pace. Use it as a model train scale calculator for switching, freight and passenger timing.
How big is 1/72 scale next to 1/48 scale? This 1/72 scale size comparison bench lets you pick a reference subject and three scales to compare diorama scale options side by side and see true relative sizes — the fastest cure for “how big is 1/72 scale”.
A scale model paint converter for the workbench: mixing ratios are scale-independent — a 3:1:1 mix is 3:1:1 for 1:700 ships and 1:24 cars alike. Enter any ratio and total volume to get exact part amounts, plus thinner for your target thinning.
Model scale explained in one table — a complete list of scale model sizes doubling as your scale model conversion chart: what one real foot becomes on the model, and how tall a 6-ft human stands. Common lookups: N scale feet to inches, HO scale feet to inches, O scale feet to inches.
Here is how to convert scale model measurements: divide the real-world dimension by the scale number. Formula: model size = real size ÷ scale. Example: a 12-foot wall in 1:87 (HO scale) becomes 12 × 12 ÷ 87 = 1.655 inches on the model. To go the other way, multiply: real size = model size × scale.
There are two directions. Real → model: divide by the scale number (model = real ÷ scale). Model → real: multiply by the scale number (real = model × scale). Keep the units consistent on both sides — if you measure the real object in inches, the model result is in inches. For 1:72, every real inch becomes 1/72 of an inch on the model (0.0139 in).
Measure a feature on the model whose real-world size you know — a door (about 6 ft 8 in), a railcar length, or a human figure (about 5 ft 9 in). Divide the real size by the model size: the result is the scale number. For example, a 40-foot boxcar that measures 6.67 inches long is 480 ÷ 6.67 ≈ 72, so it is 1:72. The What-Scale tab above does this automatically and matches your ratio against standard hobby scales.
In 1:72, one inch on the model represents 72 inches (6 feet) in real life. A 6-foot person stands exactly 1 inch (25.4 mm) tall, a 40-foot boxcar is 6.67 inches long, and a 60-foot aircraft is 10 inches long. It is one of the most popular aircraft and armor scales because models stay compact while keeping good detail. To convert 1/72 scale to inches by hand, divide the real-world dimension in inches by 72.
Compute the print/scale percentage: percentage = old scale ÷ new scale × 100. Going from 1:76 to 1:35 means printing at 76 ÷ 35 × 100 = 217%. Going from 1:35 down to 1:72 means 35 ÷ 72 × 100 = 48.6%. The Rescale tab above calculates this and also resizes any dimension for you.
Pick your scale in the Ruler tab, choose imperial (graduated in scale feet) or metric (graduated in scale meters), then print with your printer set to “Actual size” / 100% — never “Fit to page”. Every sheet includes a 1-inch verification bar: measure it with a physical ruler. If it reads exactly 1 inch, your scale ruler is accurate.
One N scale (1:160) foot is 12 ÷ 160 = 0.075 inches. Common values: Z (1:220) = 0.0545 in, TT (1:120) = 0.10 in, HO (1:87) = 0.1379 in, OO (1:76) = 0.1579 in, S (1:64) = 0.1875 in, O (1:48) = 0.25 in. A full conversion table is in the reference chart below the calculator.
From smallest to largest: Z (1:220), N (1:160), TT (1:120), HO (1:87), OO (1:76, UK), S (1:64), O (1:48), and G (1:22.5). HO is the world's most popular model railroad scale; N is the favorite where space is tight. All eight are built into the preset list in the Converter tab.
The standard dollhouse scale is 1:12 — one inch represents one foot, so a 6-foot person is a 6-inch figure. Dollhouse scale sizes at a glance: 1:12 standard, 1:24 half scale, 1:48 quarter scale. Half scale is 1:24 and quarter scale is 1:48. Measure a doorway: a 1:12 door is about 6.5–7 inches tall.
Scale miles per hour: how fast the model would be going if it were full size. Convert with: smph = model speed (in/s) × scale ÷ 17.6. An HO (1:87) train moving at 12.1 in/s runs at 60 smph — a realistic mainline freight speed. The Scale Speed tab converts in both directions.
Multiply the decimal part by 16 and round to the nearest whole number, then reduce the fraction. 0.694″ × 16 = 11.1 → 11/16″. 1.3958″ becomes 1-3/8″. The converter shows the fractional equivalent automatically whenever the result is in inches.
Yes. In the 1/72 vs 1/48 question, 1:48 wins on size: a smaller second number means a larger model. a 1:48 model is 72 ÷ 48 = 1.5 times larger in every linear dimension than the same subject in 1:72 (3.375 times larger by volume). 1:48 is the classic O scale aircraft and model railroad size.
About 1:56. A 28mm figure represents roughly a 5 ft 9 in human at 1:56 to 1:60, which is why 28mm wargaming miniatures sit close to S scale (1:64) railroad figures. 32mm figures are roughly 1:54.
No — mixing ratios are scale-independent. A 3:1:1 paint/thinner/retarder mix is 3:1:1 whether you paint 1:700 ships or 1:24 cars. What changes is the total amount you mix and sometimes how thin you spray it. The Paint Mix tab computes part volumes from any ratio and total, plus thinner amounts for a target thinning percentage.
Yes. Architecture presets (1:50, 1:100, 1:200) are included. Note that a US architect's scale of 1/4″ = 1′ is exactly 1:48, and 1/8″ = 1′ is 1:96 — you can enter either as a custom scale.
No. Scale Model Lab runs 100% in your browser — every calculation, the ruler generator, and the comparisons happen locally with no network requests. Your measurements never leave your device.
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