Application.WorksheetFunction calls Excel functions from VBA: SUM, MAX, VLOOKUP, and most others. Application.Function (without WorksheetFunction) returns error values instead of raising errors.

Code

total = Application.WorksheetFunction.Sum(Range("B2:B50"))

• Sum

  total = Application.WorksheetFunction.Sum(Range("B2:B50")) → The sum as a number

  Faster than a loop.

• Safe VLOOKUP

  v = Application.VLookup(key, Range("A:C"), 3, False) If IsError(v) Then MsgBox "not found" → A lookup that returns an error value rather than crashing

  The safe form for lookups.

• Match

  pos = Application.WorksheetFunction.Match(key, Range("A:A"), 0) → The position of a key; raises error 1004 if missing

  Wrap in On Error or use Application.Match.

• A failed lookup raises a runtime error here; use Application.VLookup (without WorksheetFunction) to get an error value instead.
• Application.Match and Application.VLookup are the forgiving versions; test with IsError.
• Not every function is available (no IF, no INDIRECT); write those in VBA.
• Evaluate("=FORMULA") runs any formula text.

• A failed WorksheetFunction lookup raises runtime error 1004.
• Range arguments must be ranges or arrays, not addresses as text.