I didn't write this Excel formula engine. Here is why I trust it anyway

Description and use

SharpCell is a free, MIT‑licensed Excel formula engine for .NET 8+ that matches Excel results on 256 test workbooks, supports 490 functions, and allows custom C# functions.

Problem

A .NET project needs to recalculate Excel workbooks reliably without relying on Excel Interop, manual rewrite, or expensive commercial libraries.

Outcome

SharpCell achieves 253/254 formula‑containing workbooks with 100% cell‑level agreement to Excel, covering 423 of 490 functions, and is free and MIT‑licensed.

Workflow

• Install SharpCell.Xlsx via dotnet add package
• Load workbook with XlsxReader.Load
• Call workbook.Recalculate() to compute all formulas
• Optionally add custom functions with workbook.Functions.Add
• Save or clone workbook for server use

Evidence

The result: 256 workbooks; of the 254 that contain formulas, 253 match Excel in every cell.

Source

490 functions, including dynamic arrays, LET, LAMBDA, MAP, BYROW, GROUPBY, PIVOTBY

Source

Free, MIT, no license keys

Source