For the introduction Phugpa tradition is used.

Calculation range
-Western to Tibetan date within the range of 8 february 1807 till 19 february 2167
-Tibetan to Western date in the range 1807 (Fire-Mouse) till 2166 (Fire-Tiger)

The following standards are used.

Tibetan days:
Tibetan days start at 05:00:00 and end the next day at 04:59:59
e.g. The western date 22 february 2012 at 04:59 gives
Tibetan year 2011 month 12 day 30 ( 20120221 )
and the western date 22 february 2012 at 05:00 gives
Tibetan year 2012 month 1 day 1 ( 20120222 )

As the Tibetan calendar can have additional monthes, double days and deleted days they are indicated as follows.

Monthtypes:
Normal month indicated with N
Intercalery month indicated with I
Delayed month indicated with D

Daytypes:
Normal days indicated with N
First day of double day indicated with F
Second day of double day indicated with S
Omitted days indicated with O

E.g.
2010 month 11 I Day 10 F 20101215
2010 month 11 I Day 10 S 20101216

2010 month 11 I Day 18 N 20101224
2010 month 11 I Day 19 O
2010 month 11 I Day 20 N 20101225

2010 month 11 I Day 30 N 20110104
2010 month 11 D Day 1 N 20110105