We frequently see style questions about sequential designations — numerals vs. spelling out and capitalization rules. 

For example: 

Phase 1, which includes a new nurses’ station and renovations to operating rooms in the east wing, will be completed in 2028.

We’ve been ensuring customer satisfaction since Day 1.

So, should you use numerals or spell out numerical references? Capitalize or not capitalize?

Directly from the Associated Press, here’s what you need to know about writing sequential designations:

  • Capitalize the first letter for a single designation: Act 3, Exit 2, Game 3, Phase 1, Room 6, Size 12, Stage 3, Category 4, Type 2
  • Generally use figures, but spell out ordinal numbers ninth and under. It’s Verse 1 but the first verse; Game 4 but the fourth game.

Use lowercase for plurals: sizes 6 and 8, exits 4 and 5, acts 1 and 2, verses 2 and 9.