Daniel T Li Spreadsheets

Daniel T. Li is a prominent structural engineer known for creating a massive library of over 495 specialized structural design spreadsheets available through Engineering International

SUMIFS for conditional sums: =SUMIFS(AmountRange, DateRange, ">=2026-01-01", CategoryRange, "Marketing")
COUNTIFS for counts with multiple conditions.
INDEX/MATCH (or XLOOKUP in Excel): =XLOOKUP(key, lookup_array, return_array, "Not found")
VLOOKUP only if leftmost-key constraint is acceptable.
FILTER (Sheets/Excel dynamic): =FILTER(Transactions, (Transactions[Date]>=A1)*(Transactions[Date]<=B1))
UNIQUE + SORT for deduped lists: =SORT(UNIQUE(CategoryRange))
TEXT and VALUE for conversions, e.g., =DATEVALUE("2026-04-11") or =TEXT(A1,"yyyy-mm-dd")
IFERROR wrapping: =IFERROR(formula, "")

He is currently working on "Project LET" —a series of spreadsheets that utilize the new Excel LET function to let users define variables inside formulas, essentially turning spreadsheets into functional programming languages without writing a single line of VBA. daniel t li spreadsheets

Visual clarity: Using conditional formatting to highlight what matters. Daniel T

Demo Versions: Free "limited" or demo versions are often available for download on the official site so engineers can test the input/output interface before committing to a professional license. He is currently working on "Project LET" —a