FormulaEngineer for .NET

Evaluate Excel formulas in C# without Excel or COM interop

FormulaEngineer reads, writes, and recalculates Excel (.xlsx) files directly inside .NET applications. Use it when workbooks are generated, uploaded, modified, or recalculated on a server without opening Excel.

Get on NuGet View supported functions

No Excel installed No COM automation Server-side .NET

Program.cs

using FormulaEngineer.Api;

using var reader    = new ExcelReader("sum.xlsx");
using var evaluator = new ExcelFormulaEvaluator();

using var sheet = reader.OpenWorksheet("Data");
var result = evaluator.EvaluateCell(sheet, row: 4, col: 1);

Calculate workbook logic in pure managed .NET.

Why formula evaluation matters

Reading cached values is not the same as recalculating formulas

An .xlsx file may contain formula results saved by Excel earlier — but there is no guarantee a cached value is present at all. Even when it is, it can be missing, stale, or wrong after inputs change in code. FormulaEngineer focuses on recalculating the workbook logic, not just reading old saved results.

See what it does View pricing

Useful for uploaded files, generated reports, APIs, and background jobs

Cached value from file

Old result

After input change

Formula must be recalculated

FormulaEngineer

New calculated result

Built for Excel-style behavior

References, ranges, errors, lookups, dates, text, and more

Formula evaluation is more than parsing strings. FormulaEngineer handles workbook references, range behavior, Excel-style errors, type coercion, lookup functions, date functions, text functions, and circular reference detection.

Explore supported functions Start free trial

Supports 410+ Excel functions and growing

SUMIFS XLOOKUP VLOOKUP INDEX MATCH WORKDAY DATE TEXT IFERROR COUNTIFS HLOOKUP DAYS360

Read, write & recalculate

Open existing workbooks, create new ones, and evaluate formulas instead of relying on cached .xlsx values.

Excel-style behavior

Handles ranges, references, coercion, errors, and circular references.

Server-side ready

Designed for ASP.NET, APIs, Linux, containers, and background jobs.

Machine hash calculator

Generate the unique hash needed for your FormulaEngineer license.

How to find your hardware identifiers

1
Open PowerShell as your normal user (no admin needed).

CPU ID

Get-CimInstance Win32_Processor | Select-Object -ExpandProperty ProcessorId

Motherboard serial

Get-CimInstance Win32_BaseBoard | Select-Object -ExpandProperty SerialNumber

4
System drive volume serial
```
cmd /c vol C:
```

1
Open a terminal as your normal user. Some commands may need sudo.
2
CPU ID (machine ID)
```
cat /etc/machine-id
```
3
Motherboard serial
```
sudo cat /sys/class/dmi/id/board_serial
```
4
Root volume UUID
```
findmnt -n -o UUID /
```

1
Open Terminal (Applications → Utilities → Terminal).

Platform UUID (enter in the CPU ID field)

ioreg -rd1 -c IOPlatformExpertDevice | awk -F'"' '/IOPlatformUUID/ { print $(NF-1); }'

3
Motherboard serial — macOS doesn't expose one. Leave that field blank.

Volume UUID

diskutil info / | awk -F': *' '/Volume UUID/ { print $2; }'

Enter your values (all fields required)

Windows