After posting the unhappy news that newspaper ads are at 1965 levels, I thought it might be interesting to take a look at how much revenue newspapers get from their print readers versus their online ones. It offers a reality check as newspapers try to figure out where to go from here.

Print newspapers took in $34.7 billion in ad revenue last year and had 49 million subscribers and newsstand sales. That works out to $709 per unit of circulation (Unlike my “1965” post, I’m not using Alan Mutter’s 2009 estimates, $28.1 billion, since I don’t have an estimate on 2009 circulation. Using his ‘09 estimate, the print figure drops to $573 per unit of circ. But total subscribers and newsstand sales will fall, too, by an as-yet-undetermined amount. If they fall 4 percent, that will work out to about $603 per subscriber). *

Newspapers online had $3.1 billion in ad revenue last year and averaged 67.3 million unique visitors per month. That’s $46 per reader.

$709 (or even $603) versus $46. And you wonder why newspapers still like their print products.

But that doesn’t even tell the whole story, because, recall, newspapers still cling to that 19th Century business model known as getting customers to pay you money. Alas, the most recent data I can find on industrywide circulation revenue is from 2004, and the Newspaper Association of America hasn’t returned my calls or emails.

So let’s go with that 2004 number, which was $11 billion. Yes, I know circulation has declined 11 percent since then, but I’m making a somewhat-educated guess that increases in newsstand and subscription prices have offset that—at some major papers, circulation revenues have actually been growing while circulation itself declines.

Add that circulation revenue to ads and the print newspaper had about $45.7 billion in revenue last year. That works out to $940 per unit of circulation ($834 under Mutter’s 2009 estimate and the guesstimated 4 percent circulation decline). *

To repeat: $940 per print subscriber or newsstand buyer versus $46 per online reader. $45.7 billion versus $3.1 billion. That means a print purchase is worth more than 20 times the revenue an online reader is. This is going down, of course. While last year a print unit of circulation brought in twenty times as much revenue as an online reader, this year that number will decline to somewhere around eighteen, assuming the above estimates. *

And if anything, these numbers understate the disparity. I don’t have any idea how much newspapers get for things like reprints and syndication, though those don’t comprise a major part of the revenue pie.

The boilerplate caveat: These numbers are revenue, of course, not profit. Production costs eat up much more of print revenue than they do of online.

Now, some will holler that it’s apples and oranges comparing online readers to print paying customers because there are multiple readers per unit of circulation for a print paper.

My point is about paying customers, but okay. There are roughly two readers per copy of the print newspaper, so that would bring the number to about $470 per reader ($417 with the FY09 estimates) versus $46 per online reader, which matches up pretty neatly with the famed, lamented ten-to-one ratio that afflicts newspapers’ digital hopes.

And you don’t want me to run the numbers on online subscriptions versus print subscriptions, and anyway I don’t know of any data out there. I’ve estimated The Wall Street Journal, the only American paper to successfully charge, gets about $60 or $70 million a year from online subscriptions, which would add $1 to online revenue per reader.

Still, the online numbers aren’t as bad as they seem. Not all online newspaper readers are made equal. The top, say 10 percent of readers, who visit the home page twice a day are worth exponentially more than the bottom 10 percent, junk traffic that bounces in off Digg or some blog and which sees a page or two and spends maybe 10 seconds on the site. I wish I could quantify how much the top 10 percent are worth, but I’ve never been able to find data on that. Still, remove the junk traffic, and the online revenue per reader would rise.

Spin that how you want. Either newspapers have done a poor job of addicting more online readers to their offerings or their hardcore readers are still predominantly reading the print paper.

It’s clearly a mix of both.

So, which way to go? Attempt to protect your print franchise and hope you last long enough for an e-reader or some such thing to replace your print fixed costs? Or push your audience to the Web, cut your staff some more and pray that somehow ad CPM’s start skyrocketing?

You tell me.

ADDING: To be clear on that last paragraph: I’m not endorsing Paul Farhi’s suggestion that newspapers abandon the Web en masse. But they have to strike a better balance between their profitable and unprofitable products, while trying to build non-advertising revenue from their Web sites.

And none of this matters if print ad declines don’t stop plunging by 20 percent to 30 percent a year.

* I used the word “subscribers” several times when I actually meant subscriptions and newsstand sales. I’ve corrected that in the copy.

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Ryan Chittum is a former Wall Street Journal reporter, and deputy editor of The Audit, CJR's business section. If you see notable business journalism, give him a heads-up at rc2538@columbia.edu. Follow him on Twitter at @ryanchittum.