My NsM playback time calculator is exactly what it says.  If you have an NsM, this utility will help you figure out how long it will take to play back an NsM given either the filename of the NsM or the filesize.

You can also specify a playback speed if you expect the NsM to playback slower (due to a slow computer) or faster (with frameskip used) than real-NES speed.

Source code is provided for this utility so that you can see how to calculate the playback time of an NsM should you so desire.

There are two files you may wish to download.  One is NsMCalc.Exe: The actual executable.  The other is ZeldIntr.NsM, which is used to help determine the speed that NESticle plays back an NsM.  (You'll also need Zelda.NES in order to use that.)  However, ZeldIntr.NsM is completely optional: If you want to use standard NES speed then ZeldIntr.NsM is completely unnecessary.  This file is just to help those who don't know exactly how playing back an NsM on their system compares to the playback speed of a real NES.

How accurate are these calculations?  On a 486DX33 (running at an estimated 80/119 speed of a standard NES) NSMCalc predicted playback time of TOOGAM's Zelda 1 NoSword demo to take 5 hours, 7 minutes, 32 seconds to playback the NsM.  In reality it took 5 hours, 5 minutes and 42 seconds to load up NESticle and playback the demo. The actual 305 minutes was very very close to the 307 minutes predicted: An error of less than 1% of the total time noticed on a 5 hour NsM.  So, I feel safe to say that the calculations given by NsMCalc (when using ZeldIntr.NsM to calculate the real playback time on a particular system) are over 99% accurate.

This program is not being distributed by my site in source-code form, because it is a utility meant to be used for NsM's, which is a custom file format for use with NESticle.  Since NESticle is a program which requires DOS (or Windows 95/NT, which has DOS in it), any computer capable of running NESticle should be able to run the DOS executable available on this site.  In other words, I'm not worried about the Linux user who wants a copy of this program who can't run a DOS program, because such a user would probably have no use for this program.  In an effort to help keep my downloads directory perhaps a little bit neater, the source code is not available as a seperate download from this site.

Source code is available.  It's included in the executable available for download from this site.

Version 1.0: Original release.
Version 1.1: Minor changes, all documented in the source code.

The following two files are available here:
MS-DOS Executable 31,463 bytes
NsM to be used to measure playback time 32,672 bytes