---
slug: "ExchangeRate"
name: "ExchangeRate"
type: "Economics"
layer: "Society"
ref: "ExchangeRate#ac47"
sema_id: "sema:ExchangeRate#mh:SHA-256:ac473b9c9dc4c536a76b952a76d7c7f1cbbf61ef8092404ae98f0f73ea66acfd"
tags: ["Society","Economics"]
updated: 2026-11-11
mindscape: "bootstrap"
index_url: https://mindscape.world/scapes/bootstrap.json
url: https://mindscape.world/bootstrap/ExchangeRate/
related: ["Metric","Value","ValuePeg"]
---

# ExchangeRate

Conversion ratio between value systems

Layer: Society · Category: Economics

## Mechanism

A definable ratio between two distinct [Value](https://mindscape.world/scapes/bootstrap/Value.md) types or [Metric](https://mindscape.world/scapes/bootstrap/Metric.md)s at a specific point in time. It allows agents with orthogonal utility functions to transact.

## Invariants

- Names the source and target [Value](https://mindscape.world/scapes/bootstrap/Value.md) types and the ratio between them.
- Carries the timestamp or window over which the rate is valid.
- Invertible where there is no spread: Rate(A→B) equals 1 / Rate(B→A).

## Failure modes

- Stale rate: the window has expired and the ratio is applied anyway.
- Assumed invertibility: a spread is present and the inverse rate is computed rather than quoted.

## Data schema

```json
{
  "type": "object",
  "description": "A rate between two value types, valid over a stated window.",
  "properties": {
    "source_type": {
      "type": "string",
      "description": "Value type being converted from."
    },
    "target_type": {
      "type": "string",
      "description": "Value type being converted to."
    },
    "ratio": {
      "type": "number",
      "description": "Units of target per unit of source."
    },
    "valid_from": {
      "type": "string",
      "description": "Start of the validity window."
    },
    "valid_until": {
      "type": "string",
      "description": "End of the validity window, if bounded."
    }
  },
  "required": [
    "source_type",
    "target_type",
    "ratio",
    "valid_from"
  ]
}
```

## Builds on

- [Metric](https://mindscape.world/scapes/bootstrap/Metric.md) (Infrastructure; References)
- [Value](https://mindscape.world/scapes/bootstrap/Value.md) (Infrastructure; References)

## Used by

- [ValuePeg](https://mindscape.world/scapes/bootstrap/ValuePeg.md) (Society; Yields)

## Identity

- Sema ID: `sema:ExchangeRate#mh:SHA-256:ac473b9c9dc4c536a76b952a76d7c7f1cbbf61ef8092404ae98f0f73ea66acfd`
- Ref: `ExchangeRate#ac47`
- Supersedes:
  - `sema:ExchangeRate#mh:SHA-256:be292881aae1af318995e3c0617ed90f9871d2d7e1c6c64e8083fa9a1b3b94f6`
  - `sema:ExchangeRate#mh:SHA-256:eadb7e9b1d80ab8649e81786e787373fd234ae5f949fd84525795ddd5525b729`

## Links

- [Pattern page](https://mindscape.world/bootstrap/ExchangeRate/)
- [View in the interactive graph](https://mindscape.world/bootstrap/#ExchangeRate)
- [JSON](https://mindscape.world/scapes/bootstrap/ExchangeRate.json)
- [Index of all patterns](https://mindscape.world/scapes/bootstrap.json)