Time calculations...incorrect math

Abe Frohman

Active member
Apr 21, 2004
I was suprised to see in v1.9.6 that the time conversions from HH:MM to hours.tenths is still incorrect. I know many companies do it different for payroll purposes...I'm just talking about the mathmatically correct method, ie, 57 min=57/60 hr=0.95 hr=round up to 1.0 hr.

Here's what LBPro does versus what's correct:

1-2 min=0.0; this is correct
3-8 min=0.1; this is correct
9-14 min=0.2; this is correct
15-20 min=0.3; this is correct
21-26 min=0.4; this is correct
27-33 min=0.5; should be 27-32 min=0.5
34-39 min=0.6; should be 33-38 min=0.6
40-45 min=0.7; should be 39-44 min=0.7
46-51 min=0.8; should be 45-50 min=0.8
52-57 min=0.9; should be 51-56 min=0.9
58-60 min=1.0; should be 57-60 min=1.0

Looking forward to a fix for this...maybe make it customizable...

This is the government conversion system most commonly used. The conversions are correct in Logbook Pro as it stands. In the next major version there will either be choices from the various conversion systems, or a system to enter your own conversions. There are about 5-6 different conversion sets I've seen so far.

Do you have a reference to the government conversion system you mentioned? Do you agree that they are mathematically incorrect?
I've attached the AF Form 781. Page 2 has the conversion table which Logbook Pro implements. It is not a matter of mathematical correctness, this is the government approved conversion system for flight logging. It's not a simple divide by 6 either, which one would think. Hope this helps.

Wow...sure enough. I guess you could leave it up to the gov't to dofuzzy math!

I appreciate your fast relpies!