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Child's day of birth (CDC) (Nepali calendar)

KIDDOBCDC_NP_ALL (B18_x) variables are a 5-digit numeric variable.


KIDDOBCDC_NP_ALL (B18_x) reports century day code for the child's date of birth, according to Vikram Samvat, the official calendar of Nepal. This variable is only available for Nepali samples.

Century day codes (CDC) are particularly useful for checking the consistency of dates, calculating intervals between events, and imputing dates when the information for an event is missing or partially complete. They are similar to century month codes (CMC), but century day codes provide additional detail.

According to the DHS Program's "Calculating the Age of Children More Precisely" documentation,

The century day code is analogous to the century month code and gives the number of days since the beginning of 1900. The century day code for a date of birth is computed in a similar manner to the century month code, using the reported day, month and year of birth, and the reported age in years for living children, as well as an imputation process for incompletely or inconsistently reported information. Note that for simplicity in the calculation of the century day code the assumption is that 1900 is a leap year, but this is also how Excel works too. This doesn’t affect any calculations of age as all calculations are using a consistent base.
Age in years is then calculated by subtracting the century day code for the date of birth from the century day code for the date of interview, and dividing the result by 365.25 (allowing for a leap year every 4 years) and taking the integer part of the result to get completed years. For age in months, divide the difference between the date of interview CDC and the date of birth CDC by 30.4375 (365.25 divided by 12 months), and then take the integer part to get completed months.

While KIDDOBCDC_NP_ALL is calculated basically the same way as INTDATECDC_ALL, with the number of days since 1900, KIDDOBCDC_NP_ALL uses the number of days since 1900 in Vikram Samvat. This corresponds to April 14, 1843 in the Gregorian calendar.

For more information about the calculation of century month codes, see INTDATECMC (V008).


KIDDOBCDC_NP_ALL (B18_x) has no comparability problems.

All standard date variables in Nepal DHS samples are given in the Nepali calendar. The Nepali calendar, or Vikram Samvat, is a lunar calendar consisting of 12 months of 29 to 32 days each. According to the Gregorian calendar, the Nepali calendar begins in mid-April. Because the 12 months do not match the sidereal year, correctional months are occasionally added or subtracted. It is only possible to convert dates given in Vikram Samvat to the Gregorian calendar when the exact date (day, month and year) is available. Otherwise, it is only possible to approximate to the month. Vikram Samvat is approximately 56 years, 8 months, and 15 days ahead of the Gregorian calendar.

Comparability - Standard DHS

KIDDOBCDC_NP_ALL (B18_x) is included as a standard recode variable beginning in Phase VII (for Nepali samples).


  • Nepal 2016: Women age 15-49 with at least one birth.
  • Nepal: 2016-W, 2016-W