Mountain Time and Eastern Time are two different time zones which are used in the United States and Canada. One must be adequately informed on how to calculate and get the accurate time of those zones to match with other time zones of other places. The significant difference between them is actually on how to do the calculation. Mountain time zone is gotten or calculated by deducting 7 hours from the Coordinated Universal Time (UTC). That is why sometimes when something like UTC-7 is written, it is just the simple way of calculating the mountain time zone.
However, in early autumn and spring summer, 6 hours is deducted from UTC when calculating the mountain time. Another important information is that; Mountain time zone uses the mean solar time of the 105 meridian west of the Greenwich Observatory. Eastern time zone, on the other hand, is calculated by deducting 5 hours from the Coordinated Universal Time. The calculation of the Eastern time zone is based on the mean solar time of the 75 meridian west of the Greenwich Observatory.