ISOMaker

Making an ISO is easy. Finding out it was 200 MB too big for the disc, after twenty minutes of writing, is the part that wastes an afternoon.

ISOMaker measures first.

Point it at a folder and the size of the finished image appears immediately, along with the disc it fits on and how much room is left over. Nothing has been written at that point, so changing your mind costs nothing.

The figure is the image's, not the folder's. ISO 9660 rounds every file up to a 2,048-byte sector and adds its own volume descriptors and path tables, so a folder that Explorer calls 3.51 GB becomes a 3.62 GB image. A folder listing cannot tell you that. This does.

One control carries the whole answer: where the image lands between a CD at 700 MB, a DVD at 4.7 GB, a dual-layer DVD at 8.5 GB and a Blu-ray at 25 GB. Under it, in words: fits a DVD, with 0.76 GB to spare. Over 25 GB it says so plainly and suggests mounting the image or using a USB drive instead.

If the folder holds a boot file, ISOMaker finds it and offers to make the image bootable. It shows you which file it found and where, so you are agreeing to something specific rather than ticking a box and hoping. It knows the names the tools that build these trees actually write — etfsboot.com and efisys.bin from Microsoft's oscdimg, isolinux and GRUB from the Linux distributions — and where BIOS and UEFI images each have to be registered. A folder carrying one of each gets both, so the image starts on an older PC and a modern one.

A folder with no boot file is not offered the choice, because an ISO cannot be made bootable by wanting it.

When the image is finished it is opened again and read back: every file counted, every byte of file data added up, and compared with the folder it came from. It either says the image holds what the folder held, or it says what does not match. Nothing is deleted either way — a failed check is something to know about, not something to act on behind your back.

ISO 9660 Level 2 with Joliet written alongside it. That matters more than it sounds: plain ISO 9660 cuts every name down to eight characters and three, in capitals, so "Quarterly Report 2026.pdf" arrives as QUART~01.PDF. With Joliet, the names you had are the names you get.

The result is an ordinary disc image. Windows mounts it on a double-click, any burning software will write it to a disc, and VirtualBox, VMware and Hyper-V will boot from it.

While it writes, the figure on screen is real: bytes laid into the image out of the total it already measured. A large folder tells you how far along it is rather than spinning.

The name Windows shows when the image is mounted. ISOMaker suggests one from the folder and keeps it inside what the format actually allows — uppercase letters, digits and underscores, up to 32 characters — rather than silently rewriting your choice later.

No cap on the number of files, no cap on the size, and no nag at four hundred. A folder of four and a folder of forty thousand are the same two steps.

The folder is read where it sits and the image is built on your own drive. There is no account, nothing is uploaded, and the app works with no connection at all.