AES Block Size
Calculate AES Block Size instantly with the exact formula and a worked example.
AES Block Size
Plaintext lengthbytes
Key lengthbits
Mode with PKCS#7 padding, ECB/CBC (1 = yes)
Ciphertext size
112bytes
16-byte blocks
7
Padding bytes
12bytes
Encryption rounds
14
More about: AES Block Size
What it calculates
The “AES Block Size” calculator computes Ciphertext size in bytes from 3 parameters: plaintext length (bytes), key length (bits), mode with pkcs#7 padding, ecb/cbc (1 = yes).
Standard IT calculations for developers and sysadmins.
Example calculation
With parameters Plaintext length = 100 bytes, Key length = 256 bits, Mode with PKCS#7 padding, ECB/CBC (1 = yes) = 1 the result is 112 bytes (The AES block size is always 128 bits (16 bytes)).
How to use
- Enter plaintext length, key length and mode with pkcs#7 padding, ecb/cbc (1 = yes) — each field above is adjustable with a slider.
- Ciphertext size (bytes) is calculated automatically as you type.
- Check the worked example below to see the formula applied to real numbers.
- Copy the result or bookmark this calculator.
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FAQ
How is AES Block Size calculated?
The AES Block Size calculator computes Ciphertext size (in bytes) from plaintext length, key length, mode with pkcs#7 padding, ecb/cbc (1 = yes). Enter your values above and the exact formula is applied instantly; a worked example with real numbers is shown below.
Is the AES Block Size calculator free?
Yes. It is completely free, needs no signup, runs entirely in your browser, and sends no data to any server.
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