What's the difference between SHA-384 and SHA-512?

SHA-384 runs the exact same 64-bit SHA-512 compression function internally but starts from different initial values and truncates the output from 512 bits down to 384 bits. It's not a separate algorithm design, just a shorter, differently-initialized output of SHA-512, similar to how SHA-224 relates to SHA-256.

Where is SHA-384 actually used?

It's a named option in several TLS cipher suites (particularly ones pairing with ECDSA P-384 curves), some certificate authorities, and standards like TOTP-adjacent HMAC configurations that want more digest length than SHA-256 without jumping to the full 512-bit output. Outside of matching a spec that names it, most new designs reach for SHA-256 or SHA-512 directly.

Is SHA-384 more secure than SHA-256?

It offers a larger security margin in raw bit-length terms (192 bits of collision resistance vs. SHA-256's 128), but both are considered secure against any known practical attack today. Choosing SHA-384 over SHA-256 isn't usually a meaningful security upgrade in practice, it typically comes down to matching a specific protocol or compliance requirement that names it.

Does this tool send my text to a server?

No. SHA-384 is computed entirely client-side using an audited JavaScript implementation, so nothing you type here is transmitted anywhere.

SHA-384 Hash Calculator - Calculate SHA-384 Checksum Online

Overview

Introduction

SHA-384 sits between SHA-256 and SHA-512 in output size, and it exists less as a distinct design than as a truncated, re-initialized view of SHA-512's internals, aimed at contexts that want more digest length without the full 512 bits.

This tool computes SHA-384's 384-bit digest of your input text entirely in your browser, useful for matching TLS cipher suite requirements or reproducing known test vectors.

What Is SHA-384 Hash Calculator?

SHA-384 is part of the SHA-2 family published by NIST (FIPS 180-4), built on SHA-512's 64-bit compression function but truncated to a 384-bit output, shown as 96 hexadecimal characters, using its own distinct initial hash values.

Because the underlying compression function operates on 64-bit words rather than SHA-256's 32-bit words, SHA-384 (like SHA-512) tends to run faster than SHA-256 on 64-bit hardware, despite the longer output.

How SHA-384 Hash Calculator Works

Your text is UTF-8 encoded, padded per the Merkle–Damgård construction to a multiple of 1024 bits, and processed in 128-byte blocks through 80 rounds of 64-bit bitwise operations and modular addition.

The output is formed from six of the eight resulting 64-bit words (384 bits total), rather than all eight as SHA-512 uses, then hex-encoded into the 96-character digest.

When To Use SHA-384 Hash Calculator

Use SHA-384 when a specific TLS cipher suite, certificate authority policy, or protocol explicitly requires it, commonly alongside ECDSA P-384 in TLS 1.2/1.3 configurations.

For general-purpose hashing without that constraint, SHA-256 or SHA-512 are more common defaults; SHA-384 is rarely the first choice for a brand-new design.

Often used alongside SHA-512 Hash Calculator and SHA-256 Hash Calculator.

Features

Advantages

Larger security margin (192-bit collision resistance) than SHA-256's 128-bit margin.
Runs on the same fast 64-bit compression function as SHA-512, often faster than SHA-256 on modern 64-bit CPUs.
Matches specific TLS cipher suite and certificate authority requirements that name it explicitly.

Limitations

Less commonly required than SHA-256 or SHA-512, so tooling and documentation examples are sparser.
No meaningful practical security advantage over SHA-256 for most applications; both are currently unbroken.
Longer output than SHA-256 means more storage/transmission overhead for the same practical security level in most threat models.

Examples

Hashing a short greeting

Input

Hello, world!

Output

55bc556b0d2fe0fce582ba5fe07baafff035653638c7ac0d5494c2a64c0bea1cc57331c7c12a45cdbca7f4c34a089eeb

13 bytes of UTF-8 text produce the standard 96-character SHA-384 hex digest.

Hashing the classic pangram

Input

The quick brown fox jumps over the lazy dog

Output

ca737f1014a48f4c0b6dd43cb177b0afd9e5169367544c494011e3317dbf9a509cb1e5dc1e85a941bbee3d7f2afbc9b1

A widely published SHA-384 test vector, useful for confirming any implementation matches the standard.

Best Practices & Notes

Best Practices

Choose SHA-384 to match a specific protocol or cipher suite requirement, not as a default general-purpose hash.
On 64-bit hardware, prefer SHA-384/SHA-512 over SHA-256 if raw throughput matters, they're typically faster despite the longer output.
Don't assume SHA-384 is meaningfully more "secure" than SHA-256 in practice; both are currently unbroken for any known attack.

Developer Notes

This tool uses @noble/hashes' SHA-2 implementation, which shares SHA-512's 64-bit compression function across the SHA-384 variant and simply swaps initialization vectors and truncates output, computed synchronously from the UTF-8 byte encoding of your input.

SHA-384 Hash Calculator Use Cases

Matching a TLS cipher suite or certificate authority requirement that specifies SHA-384
Reproducing a known SHA-384 test vector while debugging another implementation
Working with protocols that pair SHA-384 with ECDSA P-384 signatures
Cross-checking a digest from a system that already outputs SHA-384 hashes

Common Mistakes

Assuming SHA-384 is a completely separate algorithm from SHA-512 rather than a truncated, re-initialized variant.
Choosing SHA-384 by default instead of the far more common SHA-256 or SHA-512 without a specific reason.
Expecting SHA-384 and SHA-512 digests of the same input to share a common prefix, they don't, since the initial hash values differ.

Tips

If nothing specifically requires SHA-384, the SHA-256 or SHA-512 tools are the more common, equally secure choices.
On 64-bit systems, SHA-384/SHA-512 often outperform SHA-256 despite their longer output, worth knowing if raw hashing throughput matters.

SHA-384 Hash Calculator