Formats & Image Data · Tool 10

Scan, Pixel, and Print Size Calculator

About this calculator

What is the maximum size a scan can be printed at? How many pixels can you expect at 4,000 ppi? And why is a 16-bit file so much larger? This calculator helps clarify the various measurements that often get mixed up when scanning and printing.

You can start with the film frame, existing pixel dimensions, or a desired print size. The calculation shows you the image data and an uncompressed size estimate. The actual image quality ultimately depends on the level of detail that the film, lens, and scanner actually provide.

Do the math, then give it a try.

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How to Use the Calculator

Select the starting point. When referring to the film format, this means the scanned image area, not the outer edge of the film.
Specify the output resolution in ppi. To estimate memory usage, select the number of channels and bits per channel.
Check the pixel dimensions, megapixels, print size, and raw data volume. Use the file size as a guide, not as a prediction of your JPEG file.

What's Behind the Bill

Pixels = millimeters / 25.4 × scan ppi; print width in cm = pixel width / output ppi × 2.54

PPI stands for pixels per inch. A printer's DPI, on the other hand, refers to its dots per inch. The two are related but are not exactly the same. Therefore, a high printer DPI does not automatically require the same PPI value in the image file.

The amount of data is calculated by multiplying the number of pixels by the number of channels by the number of bits per channel, then dividing by eight. RGB with 16 bits per channel requires twice as much uncompressed image data as RGB with 8 bits. MB and MiB are displayed separately because the units are defined differently.

During scanning, values are rounded to whole pixels. For a desired print size, values are rounded up to ensure that the requested output resolution is not reduced by rounding down. Layers, metadata, thumbnails, and compression are added to actual files or affect their size.

An example to work through

6,000 × 4,000 pixels equals 24 megapixels. At 300 ppi, that corresponds to 50.8 × 33.87 cm. RGB with 16 bits per channel requires 144 MB of raw image data for this.

Here's what you should keep in mind

A higher nominal scan resolution does not automatically mean more detailed images.
The appropriate print resolution depends, among other things, on the subject matter, the printing process, and the viewing distance. 300 ppi is a common starting point, not a strict quality threshold.

Frequently Asked Questions (FAQ)

How large can I print an image that is 6,000 × 4,000 pixels?

At 300 ppi, 6,000 × 4,000 pixels result in a print size of 50.8 × 33.87 cm. At a lower output resolution, a larger print is possible. Whether it looks convincing also depends on the subject matter, actual sharpness, printing process, and viewing distance.

What is the difference between ppi and dpi?

PPI stands for pixels per inch. DPI refers to dots per inch on a printing device. A printer may use multiple dots to reproduce a single pixel. Therefore, the printer's nominal DPI value is not the same as the PPI value required for your image file.

Is 300 ppi absolutely necessary for every print job?

No. 300 ppi is a common starting point for detailed prints viewed at close range. Large images are often viewed from a greater distance and can look good even at a lower ppi. The key factors are the print service provider’s specifications and a quality assessment appropriate for the image.

Do higher scan ppi or 16-bit resolution automatically result in more image detail?

A higher nominal scan ppi produces more pixels, but only provides additional detail if the film and scanner are capable of resolving it. 16 bits per channel increase the possible tonal range, not the spatial resolution. With the same number of pixels and channels, they double the amount of uncompressed data compared to 8-bit.

Why does the calculated file size differ from that of my TIFF, JPEG, or RAW file?

This output describes only the uncompressed pixel values. Metadata, thumbnails, layers, and file structure can increase the file size; compression can reduce it. With JPEG, the file size also depends heavily on the subject and quality level. The calculated raw data volume is therefore not a prediction of the actual file size.