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Poster Scaling Calculator

Work out poster scaling instantly with clear inputs, formula shown and shareable results.

About Poster Scaling Calculator

Scaling multiplies both dimensions by the same factor, and because the pixel count is unchanged the effective resolution falls in inverse proportion to that factor. Posters are viewed from further away, so 150 dpi is usually enough, which is why an A3 file can be enlarged to A1 without visible loss.

Formulas

Target height

height = original height x target width / original width

Effective resolution

new dpi = original dpi / scale factor

Worked example

With the default values below, Poster Scaling Calculator returns Target height to keep proportions of 93.33. Change any input above and every figure here is recalculated in your browser.

Inputs used

Original widthminimum 0.1 cm
30 cm
Original heightminimum 0.1 cm
40 cm
Target widthminimum 0.1 cm
70 cm
Original file resolutionminimum 1 dpi
300 dpi

Results

Target height to keep proportions
93.33 cm
Scale factor
2.3333 x
Effective resolution after scaling
128.6 dpi
Quality assessment
Acceptable viewed from a distance

Step by step

  1. 1Values used
  2. 2Target height
  3. 3Effective resolution
  4. 4Target height to keep proportions= 93.33 cm
  5. 5Scale factor= 2.3333 x
  6. 6Effective resolution after scaling= 128.6 dpi
  7. 7Quality assessment= Acceptable viewed from a distance

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Poster Scaling figure worked out?

height = original height x target width / original width. Scaling multiplies both dimensions by the same factor, and because the pixel count is unchanged the effective resolution falls in inverse proportion to that factor.

Why does this matter?

Posters are viewed from further away, so 150 dpi is usually enough, which is why an A3 file can be enlarged to A1 without visible loss.

What do I need to enter?

Enter original width, original height, target width, original file resolution. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.

Related Calculators

Poster Scaling Calculator | Calcrivo