Finance-ready • Offline • Deterministic • Audit trail

Deterministic CSV conversion for finance teams.

Manual CSV imports are a compliance risk. When you open a CSV, Excel guesses types and silently rewrites values (IDs, leading zeros, dates, long numbers). SterileCSV converts CSV → XLSX offline with deterministic rules and an audit trail — so what you reconcile is what you received.

Offline by design: no uploads, no telemetry.
Deterministic rules: consistent types across machines and runs.
Audit trail: output workbook includes a Summary sheet with SHA-256.

RUN THE CORRUPTION TEST Buy License — from €99

See the proof demo • Send to your boss

AUDIT FAILED (EXAMPLE) Silent alterations detected

Excel auto-formatting is not a controlled import process.

004921

Raw CSV

→

4921

Excel (leading zeros dropped)

123456789012345678

Raw CSV

→

1.23457E+17

Excel (precision lost)

03/04/2026

Raw CSV

→

US/EU mismatch

Excel (locale-dependent date)

Run a local risk scan on your file: sterilecsv.com/kit

Before / after

Left: Excel interprets CSV cells (strips leading zeros, evaluates =/@ as formulas). Right: SterileCSV stores as text, preserving the exact value safely.

The 10-second test

Download test CSV

Steps to reproduce

Download the sample .csv file.
Open it directly in Excel.
Observe the damage: zeros disappear, long IDs lose digits.

→ Then verify with the proof demo

PowerShell (create it yourself)

@' 
id,account,amount,note
00123,00004567,12.30,"=SUM(1,1)"
00124,123456789012345678,-1,"@SUM(1,1)"
'@ | Set-Content -Encoding UTF8 .\test.csv

The hidden liability: Excel auto-formatting

Excel was built for analysis, not data transport. When you open a CSV, Excel guesses column types. For financial records, a guess is an error.

Leading zeros dropped: IDs like 00123 become 123.
Precision loss: long identifiers (16+ digits) can lose digits via scientific notation.
Locale-dependent dates: 03/04/2026 means different things on different machines.
CSV injection risk: values starting with =, +, -, or @ may be interpreted as formulas.

Operational impact

Month-end close is not the time to discover that a “General Ledger ID” was treated as a number. Standardize the import step so your reports don’t depend on Excel’s guesses.

Proof demo (runs in your browser)

Runs locally in your browser. No server uploads. No storage.

Demo limits: 50 rows • 200 KB • 10s. Desktop app has no limits.

Includes leading zeros, long IDs, ambiguous dates, decimal separators, and formula prefixes.

Download sample CSV

Try your own CSV?

This in-browser demo is prebuilt to guarantee no uploads. For real conversion on your file, use the Windows desktop app.

Get desktop app (Windows) Buy license (one-time)

AUDIT FAILED

Simulation based on common Excel import behavior; exact results depend on Excel version and locale.

Deterministic summary

Input SHA-256:

Output SHA-256:

Excel risk (simulation)

Input	What Excel may do

DESTRUCTIVE: Excel guesses data types, dropping zeros and allowing formula code to execute automatically.

SterileCSV output (demo)

Input	Stored / shown

SAFE: Every cell is explicitly typed as Text or ISO-Date. Formulas are neutralized but kept intact.

Download a clean XLSX

The workbook stores sensitive-looking fields as text so Excel won’t mutate them on open.

Compare: open the CSV directly in Excel (watch values mutate), then open the XLSX (values preserved).

Open the Summary sheet and verify Determinism SHA-256 equals .

Next step

If your reconciliation matters, don’t open CSVs directly in Excel.

Get desktop app (Windows) Buy license (one-time)

Used for…

bank exports
ERP dumps
vendor lists
payment references
reconciliation pipelines

Offline, no telemetry

Runs locally on Windows. No uploads, no tracking. See Privacy.

Deterministic SHA-256

Every workbook contains a Summary sheet with row counts, schema details, and a reproducible SHA-256 hash.

Refund window clarity

Orders can be cancelled/refunded before a license is issued. License issuance is automatic after payment; once license.json is delivered, all sales are final (except where mandatory law requires otherwise). See Refunds.

Deterministic type rules (no locale guessing)

Preserves leading zeros (e.g., in numeric IDs) and strictly enforces types. Same input → same types → same output.

Formula Neutralization

Recursively inspects fields to neutralize dangerous prefixes (=, +, -, @) that allow CSV Injection attacks.

Excel Auto-Formatting

Generates polished workbooks with frozen header panes (A2), auto-calculated column widths, and correct data types.

Audit-Ready Summaries

Includes a "Summary" sheet in every workbook with row counts, schema details, and a deterministic SHA-256 hash.

Ed25519 Security

Offline-activated licenses signed with high-security Ed25519 cryptography. No verification servers.

Zero-Trust Processing

100% offline. No cloud uploads, no telemetry. Your sensitive data never leaves your local machine's RAM.

Don't let Excel turn your data into a headline.

GENE NAMES

Scientific bodies renamed 27 human genes (like MARCH1) because Excel kept converting them into dates.

MI5

Bugged 134 wrong phones due to a spreadsheet formatting error (2010).

JP MORGAN

$6 Billion "London Whale" loss exacerbated by copy-paste spreadsheet errors.

Built for mission-critical data

SterileCSV is the standard choice for professionals who cannot afford silent data corruption.

Finance & Banking Audit & Compliance Accounting Firms Data Engineering Regulatory Reporting

✅ SterileCSV is: A portable Windows tool for secure, deterministic CSV to XLSX conversion.

❌ SterileCSV is NOT: A cloud service, an Excel add-in, or an AI data-cleaning toy.

Is SterileCSV right for you?

✅ What it does

Converts CSVs to Excel (XLSX) securely.
Automatically formats columns & types.
Produces auditable .xlsx and .manifest.json files.
Works 100% offline on Windows (no internet required).

❌ What it doesn't do

It does not edit data (use Excel for that).
It does not repair corrupted files.
It does not run macros or VBA scripts.
It does not connect to any servers.

System Requirements & Delivery

Windows 10/11 (64-bit) • No admin rights required • No Python install needed

Delivered as a portable archive. Your personalized license.json is sent automatically after payment (typically within minutes).

First Run Notice

You may see a "Windows protected your PC" (SmartScreen) popup. This is normal for specialized software not yet in Microsoft's global whitelist.

To install: Click More info → Run anyway.

Simple one-time pricing

Solo

€99

1 user / 1 device

Ideal for freelancers and solo analysts.

Team

€499

10 users / 10 seats

Accounting firms and finance teams.

Updates & Renewal: Licenses are perpetual for the version you buy. You get 12 months of free updates. After that, you can keep using your version forever, or renew only if you want newer versions.

Delivery: License fulfillment is automatic (typically within minutes).
Refunds: Orders can be cancelled/refunded before a license is issued. Once license.json is delivered, all sales are final (except where mandatory law requires otherwise).

Support

Email: contact@sterilecsv.com

Automated fulfillment • Usually within minutes.

Frequently Asked Questions

Why not just use Excel’s import wizard?

The wizard requires 12+ clicks per file and relies on human vigilance. SterileCSV automates this in one click, ensuring no column type is ever guessed wrong.

Does it change my original CSV data?

Never. SterileCSV treats your source file as read-only and generates a separate .xlsx workbook and a .manifest.json hash for your audit trail.

Do I need to install Python or runtimes?

No. SterileCSV is a standalone Windows archive. It includes its own private Python runtime and requires no administrator rights to run.

How long does license delivery take?

Licenses are delivered automatically after payment, typically within a few minutes. If you don’t receive it within 15 minutes, contact support.