# Grades & Study Calc – Percent to Letter Grade

> Grades & Study Calc – Percent to Letter Grade is a paid API for AI agents from grades-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Converts a percentage score to a US letter grade (with optional plus/minus), 4.0 GPA points, and the points needed to reach the next grade up.

## Facts

- Endpoint: GET https://grades-calc.x402tookit.com/percent-to-letter?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/grades-study-calc-percent-to-letter-grade-75cb138d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tWKlzpfLrIxpxpTqH4GZF

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 grades-study-calc-percent-to-letter-grade-75cb138d
```

Example prompt: I got an 87% on my midterm — what letter grade is that on the US plus/minus scale, and how many points away am I from the next grade up?

## When to prefer this

Use this endpoint when you need a fast, deterministic conversion of a US percentage score to a letter grade with optional plus/minus granularity and GPA points — especially when you also need to know how close the score is to the next grade tier. Prefer it over manual lookup tables or GPA calculators that don't handle plus/minus or proximity to the next grade.

## Known failure modes

- Missing required 'percent' query parameter returns an error
- Percent value outside 0–120 range may return an error or unexpected result
- Invalid plusMinus or roundHalfUp string values may be ignored or cause errors
- Network or service unavailability returns a non-200 response

## How this service works

Letter grade and 4.0 GPA points for a percentage on the common US scale, with plus/minus, and points to the next grade.

## Output

Returns the letter grade (e.g. B+), 4.0 GPA points for that grade, the lowest percentage that earns this letter, how many percentage points are needed to reach the next letter up, whether the grade is typically passing, the percent actually used in the calculation, and metadata like source and summary.

## 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": [
      "percent"
     ],
     "properties": {
      "percent": {
       "type": "number",
       "description": "Score in percent, 0 to 120"
      },
      "plusMinus": {
       "type": "string",
       "description": "false for a plain A/B/C/D/F scale (default true)"
      },
      "roundHalfUp": {
       "type": "string",
       "description": "true to round to the nearest whole percent first, the way many teachers do (default false)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "letter": {
       "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"
       ]
      },
      "gpaPoints": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "percentUsed": {
       "type": [
        "null",
        "number"
       ]
      },
      "nextLetterUp": {
       "type": [
        "null",
        "string"
       ]
      },
      "passingTypical": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "pointsToNextLetter": {
       "type": [
        "null",
        "number"
       ]
      },
      "lowes
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/grades-study-calc-percent-to-letter-grade-75cb138d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
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