ACH File Converter

CSV to ACH Converter

Convert structured CSV payment rows into a bank-ready NACHA-formatted ACH file.

1

Source CSV file

Validate the converted payment file

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Continue with a tool that fits the next step in this workflow.

How the source table should be organized

Use one header row and one payment per row. Keep routing numbers and account numbers as text so spreadsheet software does not remove leading zeros, and keep amounts in a consistent decimal format.

Map columns to payment fields

Required receiver data

Map receiver name, routing number, account number, amount, account type, and credit or debit direction.

Batch-level settings

Confirm company ID, SEC code, entry description, effective date, service class, and ODFI identification separately from row data.

Optional identifiers and addenda

Map receiver IDs and payment-related information only when the source and selected SEC code support them.

Records created during conversion

The export creates file and batch headers, entry records, eligible addenda, batch and file controls, and type 9 padding. Counts, hashes, totals, trace sequences, and block count are calculated from the mapped rows.

Import errors to resolve before download

  • Remove totals and blank report rows.
  • Correct nine-digit routing numbers that fail checksum validation.
  • Separate rows that require a different SEC code or effective date.
  • Reconcile the imported row count and amount total with the source approval.

CSV mapping and ACH output questions

Which CSV columns are required?

Each payment needs a receiver name, routing number, account number, amount, account type, and credit or debit direction; the batch also needs approved originator settings.

Can a CSV contain both consumer and corporate payments?

The rows can be imported, but PPD and CCD belong in separate batches. Split or group them before creating the final file.

Why did a routing or account number lose a zero?

Spreadsheet software may coerce identifiers into numbers. Format those source columns as text and export the CSV again.

Which authoritative sources support this page?

Technical explanations are checked against these primary sources. Bank-specific requirements can be narrower than general format guidance.

  1. Nacha ACH File Details — Official record-field guidance, including Batch Header SEC codes and addenda capabilities.
  2. Nacha ACH File Overview — Official explanation of files, batches, entries, controls, and batch grouping.
  3. Nacha: How ACH Works — Official overview of ACH participants, consumer and corporate payments, and authorization responsibilities.
  4. Nacha Operating Rules Topics — Current rule changes and implementation topics published by Nacha.

Sources reviewed August 20, 2026. Nacha owns and maintains the linked materials.