# Budget Tracking

Track trip expenses by category, split costs between members, and visualize spending.

> **Renamed to Costs (v3.3.0, #1464):** This feature is now called **Costs** everywhere in the UI — the planner tab reads **Costs** and it is listed as **Costs** in Admin → Addons (its internal addon id stays `budget`). Screenshots and some labels on this page may still say "Budget".

<!-- TODO: screenshot: budget summary and expense list -->

![Budget panel](assets/Budget.png)

## Where to find it

Open the **Budget** tab inside the trip planner. The tab is only visible when the Budget addon is enabled.

> **Admin:** Budget is an addon. Enable it in [Admin-Addons](Admin-Addons).

![Create Budget](assets/BudgetCreateBudget.gif)

## Currency

Costs is **multi-currency** (#551). Each expense (line item) is entered in **its own currency** — pick it from the currency picker in the expense modal — and everything is converted to a single **display currency** for totals, charts and settlement. The display currency is your own preferred currency (**Settings → default currency**), falling back to the trip's currency when you haven't set one. 47 currencies are supported.

When an item's currency differs from the display currency, the modal shows the converted amount alongside the rate (`1 {from} in {to}`). The exchange rate is **frozen at entry time**, so a settled position keeps the rate it was booked at and doesn't drift as live rates move.

## Categories

Expenses are grouped into categories. Each category is shown with a small colored square indicator that cycles through a 12-color palette as you add more categories.

From the toolbar you can:

- **Add a category** — type a name and click the **+** button (or press Enter).
- **Rename a category** — click the pencil icon next to its name in the category header.
- **Reorder categories** — drag the grip handle on the left of the category header.
- **Delete a category** — click the trash icon in the category header. This deletes all expense items inside it.

## Expense items

Each category contains a table of items with the following columns:

| Column | Notes |
|---|---|
| Name | Editable inline. Read-only when linked to a reservation. |
| Total | The total cost for this item. |
| Persons | Number of persons (or member chips on multi-member trips). |
| Days | Number of days. |
| Per Person | Calculated: Total ÷ Persons. |
| Per Day | Calculated: Total ÷ Days. |
| Per Person/Day | Calculated: Total ÷ (Persons × Days). |
| Date | Optional expense date. |
| Note | Free-text note. |

Click any editable cell to edit it inline. Drag the grip handle to reorder items within a category.

Add a new item using the inline **add row** at the bottom of each category table.

## Splitting costs

The **Persons** column behaves differently depending on the trip:

- **Single-user trip** — enter a number of persons directly.
- **Multi-member trip** — a member chip picker appears. Click the edit button to open the expense modal, where you can select:
  - **Equally** — Splits the cost equally among selected members. Remainder cents (from rounding errors) are distributed deterministically and rotated using the item ID to ensure everyone is charged equally over the course of the trip.
  - **Custom** — Enter specific custom amounts for each traveler. The sum of the custom splits must balance exactly to the total price.
  - **Ticket** — Build an itemized list of expenses (e.g. Apples: $10, cake: $50, Milk: $40) and assign specific trip participants to split each individual item. Individual shares are calculated cent-perfectly, the total expense price is automatically summed, and the list of itemized splits is saved/restored across edits.

Click an assigned member chip again to mark them as **paid** (the chip shows a green ring).

![Add Expense](assets/BudgetAddExpensive.gif)

## Settlement calculator

When multiple members are assigned to expenses and there are outstanding debts between members, a collapsible **Settlement** section appears inside the total card. Click the section header to expand it. It shows the minimum number of transfers needed to settle all debts (using a greedy matching algorithm), including:

- Transfer flows: who pays whom and how much.
- Net balances: each member's overall surplus or deficit.

![Final Settlement](assets/BudgetFinalSettlement.gif)

## Budget summary

The right-hand column contains two widgets:

- **Total card** — displays the grand total in large type. On multi-member trips it also shows a per-member breakdown with a proportional bar.
- **Donut chart** — spending by category. Each segment uses that category's color. The legend always shows the amount and percentage for each category; hovering a legend row highlights it.

## Exporting

Click **Export CSV** in the toolbar to download all expenses as a spreadsheet (restored in v3.3.0, #1500). The file is semicolon-delimited with a UTF-8 byte-order mark (so Excel opens it cleanly), rows sorted by date, and is named `costs-<trip>.csv`. The columns are: **Date, Name, Category, Amount, Currency, Amount (<display currency>), Note** — each expense shows both its original amount in its own currency and the converted amount in your display currency.

## Permissions

All write operations (adding/editing/deleting items and categories, changing currency) require the `budget_edit` permission.

## See also

- [Admin-Addons](Admin-Addons)
- [Reservations-and-Bookings](Reservations-and-Bookings)
- [Trip-Planner-Overview](Trip-Planner-Overview)