# Pet Care Calc – Resting Energy Requirement (RER)

> Pet Care Calc – Resting Energy Requirement (RER) is a paid API for AI agents from pet-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Calculates the resting energy requirement (RER) in kcal/day for a dog or cat from body weight using the formula 70 × kg^0.75 and the linear shortcut approximation.

## Facts

- Endpoint: GET https://pet-calc.x402tookit.com/resting-energy?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pet-care-calc-resting-energy-requirement-rer-0ab14cb2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fZZDj3x0z4gwMW3XzR-fY

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 pet-care-calc-resting-energy-requirement-rer-0ab14cb2
```

Example prompt: What's the resting energy requirement for my 12 kg dog? Can you calculate the RER in kcal per day using both the standard formula and the linear shortcut?

## When to prefer this

Choose this endpoint when you need a precise RER calculation using the veterinary standard 70 × kg^0.75 formula, especially when you also want the linear shortcut approximation and a validity flag for that shortcut. Prefer this over general calorie calculators when you need the basal metabolic floor (RER) rather than a life-stage-adjusted daily energy requirement (DER).

## Known failure modes

- Missing required 'weight' query parameter returns an error
- Non-numeric weight value causes a validation failure
- Extremely low or zero weight values may produce nonsensical or invalid results
- Invalid unit value (not 'kg' or 'lb') may cause a processing error or default to kg
- Payment failure (x402) results in a 402 response before calculation occurs

## How this service works

Resting energy requirement (RER) in kcal/day for a dog or cat from body weight, using 70 x kg^0.75 and the linear shortcut.

## Output

Returns the pet's weight in both kg and lb, the RER calculated via 70 × kg^0.75 in both kcal/day and kJ/day, the linear shortcut RER in kcal/day, a boolean flag indicating whether the linear shortcut is valid for the given weight, a disclaimer, and metadata including source and timestamp.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "weight"
     ],
     "properties": {
      "unit": {
       "type": "string",
       "description": "kg (default) or lb"
      },
      "weight": {
       "type": "number",
       "description": "Body weight (ideal or target weight for an overweight pet)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "weightKg": {
       "type": [
        "null",
        "number"
       ]
      },
      "weightLb": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "rerKjPerDay": {
       "type": [
        "null",
        "number"
       ]
      },
      "rerKcalPerDay": {
       "type": [
        "null",
        "number"
       ]
      },
      "linearShortcutValid": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "linearShortcutKcalPerDay": {
       "type": [
        "null",
        "number"
       ]
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pet-care-calc-resting-energy-requirement-rer-0ab14cb2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from pet-calc.x402tookit.com](https://www.zero.xyz/host/pet-calc.x402tookit.com/llms.txt)