What percentage converts 1:72 to 1:48?

150%. For two reduction scales the percentage is the ratio of the denominators: 72 ÷ 48 = 1.5.

Which way round do the denominators go?

Current denominator divided by target denominator. Going to a larger model means a larger denominator on top, so the percentage is above 100%.

Does the percentage depend on the part I am measuring?

No. It depends only on the two scales, so the same percentage applies to every dimension. That is why a sample measurement is optional here — it is only there so you can check the result physically.

Is 1:48 bigger or smaller than 1:72?

Bigger. The denominator is how many real units one model unit stands for, so a smaller denominator means a larger model.

Scale conversion

Scale conversion calculator

Convert one representative scale into another — 1:72 to 1:48, 1:87 to 1:160, 1:100 to 1:50 — and get the exact resize percentage, what happens to a sample measurement, and the area and volume effects.

Scales to convert between

Current scale

Write it as 1:72, 1/72, 1 to 72 or 2:1 for an enlargement.

Target scale

The scale you want the result to be in.

Sample measurement (optional)

A part you can measure, so you can check the result physically.

Common conversions

Your answer

150%

To go from 1:72 to 1:48, resize every length to 150% — a factor of 1.5×.

The percentage depends only on the two scales, not on the object, so it applies to every dimension of the drawing or model.

Resize percentage: 150%
Scale factor: 1.5×
Reverse: 66.666666…%
At 1:72: 100 mm
At 1:48: 150 mm

Consequences of this factor

How length, area and volume change at this scale factor
Measure	Multiplier	Of original	Change
Length (k)	1.5×	150%	+50%
Area (k²)	2.25×	225%	+125%
Volume (k³)	3.375×	337.5%	+237.5%

How this was calculated

Inputs

Current scale: 1:72
Target scale: 1:48
Sample: 100 mm

Formula

k = (target representation ÷ target reality) ÷ (current representation ÷ current reality)

k = 1/48 ÷ 1/72

k = 1.5× = 150%

Derived effects

Area (k²): 2.25×
Volume (k³): 3.375×

Exact calculation state: 3/2 — displayed values are formatted from this fraction, never re-used after rounding.

Calculated by SnapScaleCalc from the values entered. Methodology

For two reduction scales this reduces to a ratio of denominators: 1:72 to 1:48 is 72 ÷ 48.

How this calculation works

A representative scale is a ratio of representation to reality. Its scale factor is the first number divided by the second: 1:72 has a factor of 1/72. Converting between two scales divides one factor by the other:

k = (1 ÷ target denominator) ÷ (1 ÷ current denominator)

Dividing by a fraction inverts it, so the expression collapses to current denominator ÷ target denominator. Worked through for the commonest pair:

1:72 → 1:48 ⇒ (1/48) ÷ (1/72) = 72/48 = 3/2 = 1.5 = 150%

And the same conversion the other way, which is the reciprocal, not 100% minus anything:

1:48 → 1:72 ⇒ (1/72) ÷ (1/48) = 48/72 = 2/3 = 0.666… = 66⅔%

3/2 × 2/3 = 1 exactly, so the round trip closes. Every conversion here is evaluated as a fraction rather than a decimal, which is why 1:87 to 1:160 reports 87/160 = 54.375% instead of a rounded 54.4% — and why chaining several conversions introduces no drift at all.

Enlargement scales

Scales above 1:1, written 2:1 or 5:1, are handled the same way — the calculator uses the full ratio rather than assuming a 1 on the left, so converting 2:1 to 5:1 gives 250% correctly.

How far apart are two similar scales?

Denominators that look adjacent are not necessarily close in the object. The figures below are the same 12 m prototype rendered at four scales, so you can see the physical consequence rather than take a verdict from us:

Scale	12 m prototype becomes	Difference from 1:72	Resize from 1:72
1:72	166.67 mm	—	100%
1:76.2	157.48 mm	−9.19 mm	94.488%
1:87.1	137.77 mm	−28.90 mm	82.665%
1:48	250.00 mm	+83.33 mm	150%

We deliberately do not label any of these “close enough”. A 5.5% difference is invisible on a small fitting and obvious on a full-length model standing next to another one; only you know which case you are in.

A conversion factor is not a compatibility ruling

This calculator answers a mathematical question exactly: what factor turns scale A into scale B. It cannot answer the physical question of whether two models or components will actually work together. That depends on the standard the parts were built to, the tolerance you can accept, and how closely the two objects will be seen or fitted — HO (1:87.1) and OO (1:76.2) share 16.5 mm track gauge while being 12% apart in scale, which is exactly why the two questions have to be kept separate.

Checking the result

Enter a sample measurement you can actually measure on the model. If a 100 mm fuselage at 1:72 should become 150 mm at 1:48, measuring 150 mm on the printed or resized output confirms the whole chain, not just the arithmetic.

What this does not tell you

This converts geometry, not parts. Fittings, fasteners, wire gauges, track gauge, couplers and printed detail do not become available just because the arithmetic works, and detail that was moulded or printed for one scale rarely reads correctly at another.

For 3D printing, the volume multiplier shown is the geometric one. It is not a filament or resin estimate for a hollow part, and a part that prints reliably at one scale can have walls or features below the printable minimum at another.

Questions people ask about this

What percentage converts 1:72 to 1:48?: 150%. For two reduction scales the percentage is the ratio of the denominators: 72 ÷ 48 = 1.5.
Which way round do the denominators go?: Current denominator divided by target denominator. Going to a larger model means a larger denominator on top, so the percentage is above 100%.
Does the percentage depend on the part I am measuring?: No. It depends only on the two scales, so the same percentage applies to every dimension. That is why a sample measurement is optional here — it is only there so you can check the result physically.
Is 1:48 bigger or smaller than 1:72?: Bigger. The denominator is how many real units one model unit stands for, so a smaller denominator means a larger model.