Calculator more accurate than Excel?

Got into a math debate with a colleague today.
Product A cost $0.05 per minute. Find the cost for 15 second.

0.05 / 60 * 15

Using Calculator, she got 0.012499999……
Using Excel, I get 0.0125

So she claims that calculator is more accurate because it gives you more decimal points….

But it doesn’t make sense. How could a caculator be more accurate than Excel? And 0.05 / 60 * 15 is also equal to 0.05 / 4 which gives you 0.0125

So why does the calculator give 0.01249999 instead of 0.0125?
0.05 / 60 will be rounded off when you use calculator. Then you times 15 on something that has been rounded, of cos the result will not be accurate.


Don’t understand why some people likes the physical caculator so much. There are so many thing that need to be caculated at 1 shot. All the raw data are already in excel and the formula is more or less the same. Instead of keying them one by one on the caculator, why not just use excel?

Besides, excel is 100% more accurate than caculator.

Lesson we learnt today:
Being slow and steady doesn’t means you’ll always be correct.
Being fast doesn’t mean you’ll be wrong.


  1. Aiyah, just format the cell to 10 decimal places and tell her that there are more nines than her calculation so her is less accurate lor..

  2. The prob is, she don’t have confidence in using Excel. She prefer to use the traditional method. Use calculator slowly count.

    Tell you, sunrise liao she haven’t finish counting.

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