# Rule of 40 Calculator — SaaS Metrics Scorer

> Rule of 40 Calculator — SaaS Metrics Scorer is a paid API for AI agents from x402.agentutility.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-11-01).

Computes a SaaS Rule of 40 score and composite health grade from ARR, growth rate, gross margin, NRR, and optional efficiency metrics

## Facts

- Endpoint: POST https://x402.agentutility.ai/rule-of-40-calculator?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-11-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/rule-of-40-calculator-saas-metrics-scorer-c851ffd9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_KMHsKz4WxdPZd-kyDaeWX

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability rule-of-40-calculator-saas-metrics-scorer-c851ffd9 -d '<json body>'
```

Example prompt: Score my SaaS company's metrics: we have $4.8M ARR, growing at 35% annually, 72% gross margins, 118% net revenue retention, a burn multiple of 1.2, and a magic number of 0.9 — what's our Rule of 40 score and grade?

## When to prefer this

Use this endpoint when you need a fast, deterministic, no-signup SaaS financial health score based on the Rule of 40 framework — ideal for VC diligence workflows, portfolio monitoring, or founder self-assessment. Prefer it over manual spreadsheet calculations or heavyweight financial modeling tools when you need a structured grade plus driver breakdown in a single API call. Because it uses a deterministic in-process calculator (no upstream API dependency), it is highly reliable and consistent.

## Known failure modes

- Missing required fields (arr, growth_rate_pct, gross_margin_pct, net_revenue_retention_pct) returns a validation error
- Non-numeric values for numeric fields cause parsing failure
- Extreme or implausible values (e.g. 10000% growth) may produce warnings but still compute
- Payment failure via x402 returns a 402 response before computation begins

## How this service works

817 pay-per-call APIs for AI agents. Every endpoint is POST /<name> and is payable in USDC over x402 on Base and Solana — no signup, no API key, just pay-per-call. GET https://x402.agentutility.ai/ returns the same catalog as machine-readable JSON.

## Output

Returns a numeric Rule of 40 composite score (e.g. 74.2), a letter-style grade (e.g. 'strong'), a breakdown of weighted driver scores (rule_of_40, NRR, etc.) with individual notes, a metrics summary, any warnings, and a plain-English recommendation (e.g. 'Proceed with standard diligence and covenant checks.')

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "required": [
      "arr",
      "growth_rate_pct",
      "gross_margin_pct",
      "net_revenue_retention_pct"
     ],
     "properties": {
      "arr": {
       "type": "number",
       "description": "Annual recurring revenue."
      },
      "magic_number": {
       "type": "number",
       "description": "Sales efficiency magic number. Optional."
      },
      "burn_multiple": {
       "type": "number",
       "description": "Net burn divided by net new ARR. Optional."
      },
      "logo_churn_pct": {
       "type": "number",
       "description": "Annual logo churn percent. Optional."
      },
      "growth_rate_pct": {
       "type": "number",
       "description": "Annual ARR growth rate percent."
      },
      "gross_margin_pct": {
       "type": "number",
       "description": "Gross margin percent."
      },
      "ebitda_margin_pct": {
       "type": "number",
       "description": "EBITDA margin percent for rule-of-40. Defaults to 0 when omitted."
      },
      "net_revenue_retention_pct": {
       "type": "number",
       "description": "Net revenue retention percent."
      }
     }
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "grade": {
       "type": "string"
      },
      "score": {
       "type": "number"
      },
      "source": {
       "type": "string"
      },
      "drivers": {
       "type": "array",
       "items": {
        "type": "object",
        "properties": {
         "name": {
          "type": "string"
         },
         "note": {
          "type": "string"
         },
         "score": {
          "type": "integer"
         },
         "weight": {
          "type": "number"
         }
        }
       }
      },
      "metrics": {
       "type": "object",
       "properties": {
        "
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "grade": "strong",
  "score": 74.2,
  "source": "deterministic in-process finance calculator; no upstream API",
  "drivers": [
   {
    "name": "rule_of_40",
    "note": "40 rule-of-40 score",
    "score": 85,
    "weight": 0.25
   }
  ],
  "metrics": {
   "arr": 4800000,
   "magic_number": 0.9,
   "burn_multiple": 1.2,
   "rule_of_40_pct": 40,
   "net_revenue_retention_pct": 118
  },
  "warnings": [],
  "calculator": "saas-metrics-score",
  "recommendation": "Proceed with standard diligence and covenant checks."
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rule-of-40-calculator-saas-metrics-scorer-c851ffd9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402.agentutility.ai](https://www.zero.xyz/host/x402.agentutility.ai/llms.txt)