> For the complete documentation index, see [llms.txt](https://docs.dataloy.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.dataloy.com/release-8.28/voyage-management-system/step-by-step-guides/voyages/maintain-voyages/operating-costs-opex/opex-on-a-voyage.md).

# OPEX on a Voyage

### Viewing OPEX Lines on a Voyage

Open the voyage drawer and navigate to the **Operating Cost** tab. The list shows all OPEX lines currently active on this voyage, with all columns visible.

***

### Managing OPEX Lines

OPEX lines on a voyage can be created, edited, and deleted independently. Changes here affect only this voyage and do not propagate back to the vessel or vessel type records.

**Adding a line:**

1. Click Create in the Operating Cost tab.
2. Enter the fields (same fields as vessel-level OPEX lines; see Maintain OPEX on a Vessel).
3. Save. The line is added and the voyage OPEX total recalculates immediately.

**Editing a line:**

All columns are editable except Opex Cost Code. Changes trigger an immediate recalculation.

**Deleting a line:**

Select the line and click Delete. The voyage OPEX total recalculates immediately.

***

### OPEX Calculation

Total OPEX is calculated as **Σ (Daily Rate × Voyage Days)** across all active lines.

If an OPEX line's currency differs from the voyage currency, the rate is converted using the exchange rate at the voyage start date before being included in the total.

The calculated total is shown in the voyage P\&L as **Total OPEX (in voyage currency)** and is deducted in the Voyage Result.

***

### Automatic Recalculation

The OPEX total recalculates automatically whenever any of the following change:

* The vessel assignment on the voyage
* Total voyage days
* Offhire days (where the offhire record has a deduction flag set)
* Any OPEX line on the voyage is added, edited, or deleted

***

### Offhire Impact

When a vessel is on offhire and the offhire record carries a deduction flag (**Deduct from Operational Cost**, **Deduct from Hire Payable**, or **Deduct from Hire Receivable**), the OPEX accrued during that offhire period is deducted from the appropriate target:

| Voyage Type              | Deduction Target |
| ------------------------ | ---------------- |
| VC Voyage (owned vessel) | OPEX cost        |

All active OPEX lines on the voyage are considered applicable to the offhire period.

> **Note:** If the OPEX currency differs from the voyage currency, conversion is applied before the deduction is made.


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