Add Hex Numbers
Quickly calculate the sum of a bunch of hex numbers. Runs entirely in your browser, so your data never leaves your device.
0 chars · 0 lines
Output
The result appears here as you type.
How to use Add Hex Numbers
- 1. Paste your hex numbers. Type or paste the hexadecimal values you want to total into the input pane. Separate them with spaces, commas or newlines; a 0x prefix is fine, and case does not matter.
- 2. Let the adder sum them. The tool parses every token as a base-16 value and adds them together as it reads. There are no settings to tune, so a list like 'a b' immediately becomes 15.
- 3. Copy the total. The sum appears in the output pane as a single hexadecimal number. Hit copy and drop it into your debugger, memory map spreadsheet or code comment.
When to use Add Hex Numbers
Add Hex Numbers is for the arithmetic you constantly need when reading addresses, offsets and sizes but never want to do in your head. Instead of converting each value to decimal, summing, and converting back, you paste the raw hex list and read off the hex total directly.
- Computing a memory address. You have a base address like 0x8000 and a chain of struct offsets from a linker map. Summing them here gives the absolute address to feed to your debugger's watch window.
- Totalling section sizes. A firmware build report lists each section's size in hex. Adding them tells you whether the combined image still fits in the 0x20000 bytes of flash you actually have.
- Checking a checksum by hand. Some simple protocols define their checksum as the sum of all payload bytes. Paste the bytes from a packet capture and compare the total against the checksum field the device sent.
- Verifying compiler math. When a disassembly shows an address computed from several immediates, you can confirm the arithmetic independently. It is a quick sanity check before you blame the toolchain for a bad jump target.
Examples
Add two hex numbers
Input
a b
Output
15
Add with a carry
Input
ff 1
Output
100
About the Add Hex Numbers tool
Add Hex Numbers does its work locally, right in the browser. Quickly calculate the sum of a bunch of hex numbers. There is no upload step, no queue and no account, and your data never travels over the network.
It belongs to the Hex Tools collection on EditSafely, a set of 108 small, focused Hex utilities that share the same instant, private workspace.
There is nothing to configure. Provide the input and the result appears on its own. 2 worked examples further down the page show exactly what the tool produces for real inputs.
Running locally also makes the tool fast and dependable: results appear as you type or drop a file, there is no server outage that can take it down mid-task, and confidential data can be processed without a second thought.
Frequently asked questions
Is Add Hex Numbers free to use?
Yes, it is completely free. All 2,658 tools on EditSafely work without an account, a subscription or usage limits.
Is it safe to paste sensitive or confidential data?
Everything happens locally. Your browser downloads the tool's code once, then does all the processing itself; nothing you enter is transmitted, stored or logged. You can even go offline after the page loads and it will still work.
How much text can I process at once?
There is no fixed limit. Because the work happens on your own device rather than on a shared server, the practical ceiling is your machine's memory, which comfortably handles inputs far larger than typical online tools allow.
Do I need to sign up or install anything?
No. The tool works in any modern browser on desktop, tablet or phone. There is no account to create, no extension to add and no software to install.
How do I use the result?
The output panel has a one-click copy button, and you can keep refining the input while you work; the result updates in place as you type.