> ## Documentation Index
> Fetch the complete documentation index at: https://docs.spreader.sh/llms.txt
> Use this file to discover all available pages before exploring further.

> ## Agent Instructions
> Spreader is a web service that tracks arbitrage spreads between crypto exchanges. This documentation covers only what a user of the service sees and does.
> Page paths starting with /en/ are English. Translations live under /ru/ and /uk/ with the same file names.
> Screenshots are illustrations. Every screenshot is accompanied by text that states the same facts, so you do not need to see the image.

# Calculator

> The Calc mode of the trade panel estimates the result of a round trip: entry and exit spreads by the order books for your size, fees, funding over a holding period, break-even and ROI.

**Calc** is the fourth mode of the **Trade** panel on the spread page. It needs no exchange keys and works for guests.

![The trade panel in Calc mode.](https://mintcdn.com/develops-6bdfff15/Di84s-PRn3sH6ZwP/images/spread/calc-en-dark.png?fit=max\&auto=format\&n=Di84s-PRn3sH6ZwP\&q=85\&s=ab48d11d35b462642db65a8c1610124d)

The trade panel in Calc mode.

## Inputs

| Field | Meaning |
| - | - |
| **Total for both legs, \$** | Size of the position. The panel shows `Long ≈ … · Short ≈ …` per leg. |
| **Taker fee, long**, **Taker fee, short** | Prefilled with the exchange fees of the two legs, editable. |
| **Holding period, days** | How long you expect to hold. |
| **Target exit spread** | The Out spread you plan to close at. **Now** uses the current Out. |
| **Entry prices** | **Book** walks the order books for your size and shows the slippage, **Best** uses the best prices and ignores depth. |

## Result

| Row | Meaning |
| - | - |
| **Entry** | Net entry spread for the size by the chosen prices. |
| **Exit** | Net exit spread at the target. |
| **Funding** | Funding income over the holding period at the current rates. |
| **Break-even** | Hours of funding needed to pay back fees and both spreads. |
| **Result** | Entry plus exit plus funding, in percent and in USD. |
| **ROI** | Result relative to the size. |

`not enough depth in the order book` means the books do not hold your size at the shown levels. `Order books are off or unavailable: the entry is calculated by the best prices` appears in Server mode.


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.