# ROAS Calculator

> Computes return on ad spend (revenue / ad spend) as a ratio and percentage, the advertising cost of sales (ACoS), and, when the gross margin is given, the break-even ROAS (1 / margin) and the gross profit left after ad spend.

- Calculator id: `roas` · Category: Business & Marketing (`business`) · Tool name: `calculate_roas`
- Canonical page: https://tttkmbb.com/business/roas · This document: https://tttkmbb.com/business/roas.md · JSON definition: https://tttkmbb.com/business/roas.json

## Purpose

Computes return on ad spend (revenue / ad spend) as a ratio and percentage, the advertising cost of sales (ACoS), and, when the gross margin is given, the break-even ROAS (1 / margin) and the gross profit left after ad spend.

**Use when:** You want to judge whether a paid campaign pays for itself: revenue per unit of ad spend and the ROAS needed to break even at your margin.

**Do not use when:** You need cost per click or per acquisition (use ad-metrics), or a full return on investment with all costs (use roi).

## Input

| Parameter | Type | Unit | Required | Description |
| --- | --- | --- | --- | --- |
| `revenue` | number |  | required | Sales revenue generated by the campaign. (min 0, max 1000000000000) |
| `ad_spend` | number |  | required | Amount spent on the campaign. (> 0, max 1000000000000) |
| `gross_margin_percent` | number | % | optional | Gross margin on the revenue (after cost of goods, before ad spend); enables break-even ROAS and profit. (> 0, max 100) |

## Output

| Field | Type | Unit | Description |
| --- | --- | --- | --- |
| `roas` | number |  | revenue / ad_spend (e.g. 5 means 5:1). |
| `roas_percent` | number | % | roas × 100. |
| `acos_percent` | number | % | ad_spend / revenue × 100 (advertising cost of sales, the inverse of ROAS). |
| `break_even_roas` | number |  | 100 / gross_margin_percent: the ROAS at which gross profit equals ad spend (only when margin given). |
| `gross_profit_after_ad_spend` | number |  | revenue × margin − ad_spend (only when margin given). |
| `assessment` | string |  | Comparison of ROAS with the break-even ROAS. |

## Formula

`ROAS = revenue / ad_spend; ACoS % = ad_spend / revenue × 100; break_even_ROAS = 1 / (gross_margin_percent/100); profit = revenue × gross_margin_percent/100 − ad_spend`

## Data Sources

- Google Ads Help – About Target ROAS bidding — https://support.google.com/google-ads/answer/6268637 (reference, retrieved 2026-09-24)
- Wikipedia – Return on investment — https://en.wikipedia.org/wiki/Return_on_investment (reference, retrieved 2026-09-24)

Data freshness: `static`. Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output.

## API

- `GET https://tttkmbb.com/api/v1/calculate/roas?revenue=…&ad_spend=…`
- `POST https://tttkmbb.com/api/v1/calculate/roas` with JSON body `{"inputs": {…}}`
- Response: unified envelope (`success`, `request`, `result.values`, `result.units`, `sources`, `freshness`, `timestamp`, `next_actions`, `links`); see https://tttkmbb.com/docs/response-format.md
- Schema: https://tttkmbb.com/api/v1/calculators/roas · OpenAPI operationId `calculate_roas` in https://tttkmbb.com/openapi.json
- Authentication: none. Rate limit: fair use, see https://tttkmbb.com/docs/rate-limits.md.

## MCP

- Server: `https://tttkmbb.com/mcp` (Streamable HTTP, JSON-RPC 2.0, no auth)
- Tool:  `run_calculator` with `{"calculator_id": "roas", "inputs": {…}}`

## Example

- Revenue 5,000 on spend 1,000, 40 % margin: inputs `{"revenue":5000,"ad_spend":1000,"gross_margin_percent":40}` → `{"roas":5,"roas_percent":500,"acos_percent":20,"break_even_roas":2.5,"gross_profit_after_ad_spend":1000}`
- Revenue 2,400 on spend 800: inputs `{"revenue":2400,"ad_spend":800}` → `{"roas":3,"roas_percent":300,"acos_percent":33.33}`

```
GET https://tttkmbb.com/api/v1/calculate/roas?revenue=5000&ad_spend=1000&gross_margin_percent=40
```

## Limitations

You need cost per click or per acquisition (use ad-metrics), or a full return on investment with all costs (use roi). All values are computed from the formula above; no measurement or live data is involved.

## FAQ

**Is a ROAS of 4 good?**

Only relative to your margin: with a 25 % gross margin a ROAS of 4 merely breaks even, with a 60 % margin it is very profitable. Compare with break_even_roas.

**ROAS vs ROI?**

ROAS divides revenue by ad spend only; ROI divides net profit by total investment including product and operating costs, so it is always lower.

## Related

- [Ad Metrics Calculator (CPM, CPC, CTR, CPA)](https://tttkmbb.com/business/ad-metrics.md) — CPM, CPC, CTR and CPA for the same campaign.
- [ROI Calculator](https://tttkmbb.com/finance/roi.md) — Return on investment including all costs.
- [Margin and Markup Calculator](https://tttkmbb.com/finance/margin-markup.md) — Gross margin needed as input here.