A useful import starts with an ordinary, well-labelled table. Keep one event per row, make the dates unambiguous and review the preview before changing the calendar. You do not need a complicated spreadsheet template, but you do need to know what each column means and what should happen to duplicate records.
Start with a small, explicit table
Give the table a title column and a start-date column. Add an end date when an event spans several days, and keep an optional time label in a separate column. For example, a row might contain “Spring trip,” 2027-03-24 and 2027-03-26. That final date is included in the event. A time label such as 14:30 remains display text rather than a time-zone appointment.
Column names do not have to match the words in the editor exactly because you review their mapping. A heading called Event name can map to Title, and Start can map to Start date. Clear headings still help you avoid selecting the wrong field. Remove unrelated summary rows and notes from the event table before saving it as CSV.
Use a date format that does not need guessing
Write dates as YYYY-MM-DD, including the year. The value 2027-03-08 is March 8, 2027. A value such as 03/04/2027 can mean different dates to different readers, so MonthSprig asks you to correct it. Decide which date the source intended rather than choosing the interpretation that happens to make the import succeed.
Check that the dates actually exist. February 29, 2027 is invalid, while February 29, 2028 is valid. An end date earlier than the start also needs attention. Do not swap those dates automatically if doing so would conceal a mistake in the source. Correct the original spreadsheet or the review row, then check the event again.
Save a CSV copy of the event table
Use a UTF-8 CSV file for the import. MonthSprig accepts files up to 5 MB and up to 2,000 event rows. If your spreadsheet contains more information, make a smaller copy with only the events you need. Keep the original spreadsheet as a separate record so cleaning the import file does not remove details you still need elsewhere.
Commas, quotation marks and line breaks can be part of an event title or note. A CSV writer should quote those fields correctly rather than splitting one event across several columns. Use your spreadsheet application’s CSV export instead of manually joining text with commas. Open a small sample in the preview to check that the fields still line up.
Map the fields, then inspect real rows
Choose the CSV file and map its columns to the calendar fields. Title and start date are the essential mappings. Review optional end dates, time labels and repetition settings deliberately. A missing optional value should not be replaced with a guess simply because a neighboring row contains something similar.
Inspect at least one single-day event, one spanning event and one repeated event in the preview. Read the year as well as the month and day. If the repeat value is monthly and the date is the 31st, remember that months without day 31 are skipped. Confirm that this is the rule you meant, not a request for the last day of every month.
Resolve errors and duplicates without overwriting work
The review step identifies rows that need attention. An invalid date remains visible so you can see and correct the original value. A duplicate ID can refer to an event already in the project or another row in the same file. Decide whether to skip that row or give a genuinely different event its own ID. Do not assume that a repeated title means the events are identical.
Keep the current project unchanged while reviewing. Confirm the import only after you have corrected or skipped the problematic rows and checked the summary. Discarding the import should return you to the existing calendar. If you are unsure about a large file, test a small copy first and make a JSON backup of the project before adding the rest.
Review the calendar after confirmation
After adding the events, inspect the affected dates in the calendar. Check long titles, several events on one day and spans crossing a month boundary. The data may be valid while the page still needs more space or shorter labels to print well. Make layout changes without altering dates merely to improve the appearance.
Save the updated project and download a fresh backup when the result is useful. If you later export event CSV for a spreadsheet, keep its safety treatment for formula-like text intact until you understand how the receiving application will interpret it. Imported labels are information to display; they should not become instructions for a spreadsheet to execute.