Panchang, panjika, jantri
The Hindu almanac goes by several names. Panchang, "five limbs", is the common one in the north; panjika or panji is used in Bengal, Odisha and Mithila; and jantri is the word of Gujarat, Rajasthan and the Hindi belt for the almanac or the year table. The names point to the same thing, a yearly book that gives the tithi, nakshatra, yoga, karana and weekday of each day, with the festivals and the muhurtas.
What a pocket almanac keeps and leaves out
A small jantri keeps what a household looks up most often: the date of each festival and fast, the month names of the year, the Sankranti days, the main muhurtas for marriage, griha pravesha and the start of work, and the days to avoid. It leaves out the long tables of planetary positions that a full panchang gives for the astrologer. The tithi of a day is given as the one present at sunrise, with the hour at which it ends where the day depends on it.
Because it is short, a jantri works best for a quick answer about a date and less well for a calculation. A person who needs the exact time of a tithi, the lagna of a muhurta or the position of a planet should use the full panchang, or the pages of this site, which give the times for the place chosen.
Using it with the other Varanasi almanacs
A household that already follows a Thakur Prasad panchang will find the Chintaharan Jantri in agreement with it on the festivals of the year, since both come from the same publishing house. The two are two sizes of the same tradition: the panchang for the pandit and the reference shelf, the jantri for the pocket and the wall.