This is a follow-up to SJ Baty's excellent post where he described a method for obtaining free U.S. census records at archive.org. The primary limitation of that website is a lack of indexing. The current 'outage' at FamilySearch for U.S. census records has caused me to re-visit archive.org as a backup source. I've come up with a tool that will help locate the right volume and page. You must already know the roll and image number from FamilySearch or MyHeritage. Example:
The tool is a free Google Sheets calculator that you'll need to copy and install on your own PC: LINK
UPDATE: Already discovered a problem. The archive.org URL varies with "unit" or "unix" appearing after the roll number. I haven't figured out the pattern, so I've added both links. If you get an error, or the wrong state or wrong census year, try the other link.
This is a dumb tool. You will need to enter any required leading zeros. In most cases, the roll number will be four digits. The exception is 1900 where three digits is common. If one way doesn't work, try another. When the roll number is seven digits, only the last three or four should be used. On FamilySearch, the roll number is often referred to as the Affiliate Film Number.
The page that is targeted will usually be very close, but not always exact because of different starting points in the images. Occasionally an image # will have a leading zero which will need to be edited on the calculated URL.
I thought long and hard about whether I should share this because it is imperfect and may cause frustration for some. If you're a programmer and would like to improve upon it, you're welcome to proceed.
I didn't find Ancestry.com citations suitable because they don't usually include the necessary information. I don't know about other sites like FindMyPast. 1930 doesn't work because it has too many variations and 1940 isn't published on archive.org I'll follow this post with examples.
