# Simple question: pixels vs file size

Discussion in 'Photoshop' started by Arizona, Sep 12, 2004.

1. ### ArizonaGuest

Why would a 2510 by 1960 image take 14.1MB in its uncompressed mode?
What's the math?

Arizona, Sep 12, 2004

2. ### SandersGuest

****************
The math is:
2510 x 1960 x bit depth (8) x number of channels (3) / 8192 = Kilobytes
Divide that by 1000 for MB.

--sanders

Sanders, Sep 12, 2004

3. ### Johan W. ElzengaGuest

2510 x 1960 = 4919600 pixels.
One pixel is 3 bytes if the image is 8 bits per pixel, so
4919600 pixels = 14758800 bytes = 14.0751 MB.

Johan W. Elzenga, Sep 12, 2004
4. ### anyoneGuest

What's 8192?

anyone, Sep 12, 2004
5. ### SandersGuest

To be precise: There are 8,192 bits in a kilobyte, not 8,000
--sanders

Sanders, Sep 12, 2004
6. ### Johan W. ElzengaGuest

Oops. Read "if the image is 8 bits per COLOR", not per pixel.

Johan W. Elzenga, Sep 12, 2004
7. ### L. M. RappaportGuest

I always thought there were 1024 bits in a kilobyte.

L. M. Rappaport, Sep 13, 2004
8. ### Aki AhonenGuest

1024 bits in kilobit
bit=1/8Byte
so 1kilobyte=1024x8bits

--Aki Ahonen

Aki Ahonen, Sep 13, 2004
9. ### CarlosGuest

Hi
That is correct.
This is incorrect. You must divide by 1024 for Mbytes.

Carlos

Carlos, Sep 13, 2004
10. ### CarlosGuest

Hi
1 byte = 8 bits
1 Kbyte = 1024 bytes = 8 x 1024 bits = 8192 bits.

Carlos

Carlos, Sep 13, 2004
11. ### L. M. RappaportGuest

You're right - I should know better.

L. M. Rappaport, Sep 14, 2004