I am not very knowledgeable about economics and am trying to reword these two sentences:

In 1964 the CDC 6600 cost around $7 million USD, though some sources site prices of up to $10 million. Given the relative value of the dollar in today’s economy, the machine would cost very much more; depending on the economic formulas used could cost $700 million.

All prices are in US dollars. The point I'm trying to make is that $7 million dollars was a lot more in 1964 than it is today, but this is hard to convey because even today $7 million is a lot.

According to here " $7,000,000.00 from 1964 ranges from $39,900,000.00 to $166,000,000.00." today.

When writing money is it correct to write the first part of the number using digits, followed by the word? For example $10 million vs $10,000,000.

  • 2
    I'm not that knowledgeable about economics either, but according to this online inflation calculator, even if we go with the (probably "inflated") original cost of $10M in 1964, that would still only be the equivalent of $75M today. So your cited source's depending on the economic formulas used obviously includes a pretty massive adjustment based on the well-established principle of "Let's just make the answer as big as possible". Commented Feb 17, 2014 at 22:10

3 Answers 3


You can actually use $7M USD to mean the same. But $7 Million USD is perfectly acceptable, if not preferable as it saves the reader from having to count the zeroes.

As far as writing out the word Million or Billion, I would say it depends upon the formality of the writing.

  • 1
    Actually "$7 million USD" is tautologous; either '$7 million (US)' or '7 million USD/ USD 7m' is better. Commented Feb 17, 2014 at 22:11
  • I hadn't actually read your answer while I was just posting my comment to the question. To be honest, I didn't even finish reading the question itself, so I didn't know he was specifically asking how to avoid cumbersome forms like $166,000,000.00. I just wrote $75M the same as most people would, because it's a quick and easy way both to write it and have it understood. But it occurs to me that although in these days of "mega-mega-mega" numbers for national budgets and such, we hear trillion all the time on the news, I don't recall reading things like US GDP for 2013 was $17T. Commented Feb 17, 2014 at 22:21
  • @TimLymington It is not tautologous. USD is the appropriate abbreviation for US currency. Yes, the $ says dollars, but most users would use $7M USD instead of $7M US.
    – David M
    Commented Feb 17, 2014 at 22:43
  • @FumbleFingers True enough, I have yet to see anyone write T in place of trillion. But, as the number becomes more commonplace, it may become necessary.
    – David M
    Commented Feb 17, 2014 at 22:48
  • If USD is 'the appropriate abbreviaton for US currency', and $ is the abbreviation for dollars, this is a tautology by definition. Commented Feb 17, 2014 at 23:58

In 1964 the CDC 6600 cost around $7 million, though some sources cite prices of up to $10 million. Accounting for inflation over 50 years, in today's money, the machine would cost about $75 million.

As for how to write the amounts, go with the earlier comments, but stay consequent.

As for the actual amount after inflation correction, please check your sources (the link you give doesn't work for me, but I assume the 75 million that was mentioned comes closer than the 700 you mention, and certainly the billions from your linked source.

I have changed site to cite, assuming it to be a simple typo :)

In your second line you try to cover yourself so much that it becomes almost unclear what you try to say. I replaced it with wording based on what I have seen in several recent articles.

Just make sure you have something good to back up the number you quote, maybe include a reference in your piece, and stick with that. Do not confuse the reader with all kinds of possible economic calculations.

I am assuming your point is the high price of the machine, not the intricacies of inflation calculation. So just focus on that high price, and just make sure the price you mention can be justified.


You ask two questions:

  1. How can I make clear that $7 million in 1964 is a lot more in today's dollars than it looks?

    In 1964 the CDC 6600 cost around $7 million USD, though some sources cite prices of up to $10 million ($40 million to $166 million in 2014 dollars, adjusted for inflation and [whatever else accounts for this variability]).

  2. Should I write out $10,000,000 or use $10 million?

    People can't intuitively and quickly translate multiple zeros and commas to amounts. Was that $10 million or $10 billion? If it's not a chart or spreadsheet, use $10 million.

    The reduction of million to M should be limited to headlines, and then, only in tabloid publications. You also run the risk of purists insisting that M is supposed to mean mille which is thousand.

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