Calculator for Grading

npx add-mcp 'https://calculatorforgrading.com/mcp?src=mcp'

Calculator for Grading runs one public MCP server (Model Context Protocol) with the same math as this site: grades from questions wrong, the score needed on a final, weighted averages, GPA, SAT, ACT and MCAT practice scores, and published grading scales with their sources. It needs no account, no login and no personal data.

Where you can use it

• ChatGPT: add the Calculator for Grading app from the ChatGPT apps directory.
• Claude (claude.ai, Claude Desktop, Claude Code): search for Calculator for Grading in the Connectors directory, or add it as a custom connector: Settings → Connectors → Add custom connector → paste https://calculatorforgrading.com/mcp?src=claude. No authentication.
• Gemini: where your Gemini plan offers custom apps, add https://calculatorforgrading.com/mcp?src=gemini as the server URL.
• Any other MCP client (Cursor, VS Code, Codex and others): use the endpoint below. The server is also listed in the official MCP Registry as com.calculatorforgrading/calculatorforgrading.

Endpoint

Transport: MCP Streamable HTTP, stateless JSON-RPC 2.0 over HTTPS POST. No sessions, no authentication, no API key. CORS is open. Server version 1.1.0.

https://calculatorforgrading.com/mcp

The optional src query parameter names the client (chatgpt, claude, gemini, gworkspace or mcp). It only tags the links the server returns, so we can see which assistant brought a visitor. It changes nothing else.

Example configuration for a client that reads a JSON settings file:

{
  "mcpServers": {
    "calculatorforgrading": {
      "type": "streamable-http",
      "url": "https://calculatorforgrading.com/mcp?src=mcp"
    }
  }
}

Quick test from a terminal:

curl -s -X POST https://calculatorforgrading.com/mcp \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'

Tools

All tools are read-only (readOnlyHint: true) and never call anything outside this site. Every answer carries a short text with a link to the matching calculator here, with the same numbers filled in, and a structuredContent object that matches the tool's output schema. The answers show no prices and no ads.

grade_calculator: Grade from questions wrong

Inputs: total_questions (integer, required), wrong (integer), correct (integer), scale (string), custom_cutoffs (array), decimals (integer), rounding (string), include_chart (boolean)

final_grade_needed: Score needed on the final

Inputs: current_grade_percent (number), final_weight_percent (number), target_grade (string | number, required), points_earned_so_far (number), points_possible_so_far (number), final_exam_points (number), scale (string)

weighted_grade: Weighted average of categories

Inputs: rows (array, required), target_grade (string | number), scale (string)

gpa_calculator: GPA from course grades

Inputs: courses (array, required), mode (string), scale (string)

test_score_calculator: SAT, ACT and MCAT practice scores

Inputs: test (string, required), practice_test (integer | string), sat_reading_writing_correct (integer), sat_math_correct (integer), act_english_correct (integer), act_math_correct (integer), act_reading_correct (integer), act_science_correct (integer), mcat_chem_phys (integer), mcat_cars (integer), mcat_bio_biochem (integer), mcat_psych_soc (integer)

grading_scale_facts: Grading scale cut-offs with sources

Inputs: scale (string, required)

Accuracy and privacy

Results are estimates for practice and planning, not an official grade, test score or admissions advice (see the terms). What the server receives and what it keeps is described in the privacy policy.