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A positive Taiwan Republic of China, or ROC, year converts to a Gregorian year by adding 1911. The month and day stay unchanged during this year-number conversion. This is useful when reading a Taiwan family record or form; it is not a Singapore calendar convention and it does not convert a Chinese lunar date.
Start with the label on the original record
Look for an explicit indication that the year is ROC rather than guessing from its length. ROC year 115 corresponds to Gregorian 2026, so ROC 115/2/17 becomes 17 February 2026 if the original month and day are Gregorian. If the record also says lunar, a separate lunar-to-Gregorian conversion is still required. Preserve the original text until both questions are settled.
Apply the formula and reverse it
ROC 1 + 1911 gives 1912. ROC 89 + 1911 gives 2000. ROC 113 + 1911 gives 2024. Subtracting 1911 from the converted year should recover the original positive ROC year. This quick check catches the common mistake of using 1910 or 1912 as the offset, or adding the offset to a year that was already Gregorian.
Validate the whole date
A correct year calculation does not make every month-and-day combination valid. ROC 113/2/29 maps to 29 February 2024, which exists. ROC 114/2/29 maps to 29 February 2025, which does not. Test Gregorian leap-year rules after conversion; applying a divisibility rule directly to the ROC number answers the wrong question. Never move an invalid date to month-end without checking the source record.
Enter the result in this language version
The Singapore English tools use Gregorian years. Calculate the year first, then enter the full Gregorian date in the date converter. The dedicated ROC input selector is available in the Taiwan version, not in this interface. Do not type 115 into a field expecting a Gregorian year and assume it will infer the intended era.
Understand the lower and upper limits
The Taiwan input mode accepts positive ROC years and does not support ROC year zero or years before that era. Knowing that ROC 1 corresponds to 1912 does not mean the site's Chinese lunar converter verifies 1912: that separate conversion range is 1950–2035. Distinguish an unsupported range from a date that never existed.
Keep records that can be checked later
Store the original era, original year, month and day, and converted Gregorian date in separate fields. When preparing birthday reminders, also record whether the celebration follows the Gregorian or Chinese lunar calendar. The calendar comparison guide explains why changing a year label and changing calendars are different operations.