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How to burn an ISO to a CD
Small ISOs — rescue tools, tiny Linux builds — fit on a 700 MB CD. cdBurner writes the image so the disc behaves exactly like the original.
An ISO file is a single-file snapshot of an entire disc — its files, its layout and any boot data. To use it you don't copy the file onto a disc; you burn the image, which recreates the original disc sector for sector. That's why a properly burned ISO can boot a PC or install an operating system.
What you'll need
- A Windows 10 or 11 PC with a CD, DVD or Blu-ray writer (internal or external USB).
- A blank disc big enough for the image — a CD holds about 700 MB — roughly 80 minutes of audio or a few hundred photos.
- Your .iso (under ~700 MB).
- The free cdBurner burn agent — a one-time, 2-second install.
Step by step
Connect the burn agent
Open onlinecdburner.com and make sure the burn agent is connected (install it once if needed).
Insert a blank disc big enough for the image
Match the disc to the image size — a CD for small images, a DVD for up to 4.7 GB, a Blu-ray for more.
Choose “ISO image”
Select your .iso (under ~700 MB).
Burn the image
cdBurner writes it sector-for-sector so the disc is bootable/readable exactly as intended. Keep Finalize on.
Tips for a clean burn
- Write the ISO as an image, never as a file copy — only an imaged disc boots or behaves like the original.
- Match the disc to the image: a CD holds about 700 MB — roughly 80 minutes of audio or a few hundred photos. cdBurner shows the fit before you start.
- Leave Finalize on so the disc is closed and reads everywhere.
Common mistakes to avoid
- Copying the .iso onto the disc as a file instead of writing the image — the disc won't boot.
- Choosing a disc that's too small for the image.
- Burning a bootable disc at maximum speed on cheap media, which can corrupt it.
Why cdBurner is different
There is no other tool on the internet that burns real, physical discs straight from a web page. cdBurner is the first of its kind.
- 100% free — no trial, no watermark, no nag screens.
- Private — files are written locally and never uploaded to a server.
- No bloatware — one small signed helper, not a heavy install.
- Built on Windows' native IMAPI2 engine, so your discs read everywhere.
Frequently asked questions
Will the burned disc be bootable?
If the ISO is a bootable image, yes — cdBurner writes it sector-for-sector and keeps the boot data intact, so the disc boots exactly like the original.
Can't I just copy the ISO file onto the disc?
No. Copying the .iso as a file gives you a disc with one file on it. You must burn the image so the disc becomes what the ISO represents.
What size disc do I need?
For this job, a CD holds about 700 MB — roughly 80 minutes of audio or a few hundred photos. cdBurner shows whether your image fits before you burn.
Is cdBurner really free?
Yes — completely free and ad-supported. No trial, no watermark and no paid tier.