Calcgrid MCP MCP server

Calcgrid provides an official MCP server exposing 737 deterministic calculators and evidence-based working-day data. It supports finance, health, math, unit conversion, and time-zone resolution using pinned IANA tzdb and source-traceable calendars for China and the UK. The server offers structured JSON responses with formulas and sources, requiring no authentication.

Endpoint and access

No sign-in: your client connects and lists tools immediately, with no account or key.

No sign-inEndpoint checked 2026-10-05Operated by Calcgrid

MCP endpoint (Streamable HTTP)

https://tttkmbb.com/mcp

Vendor documentation

What you can do with it

Calculate mortgage payments and loan comparisons
Convert between solar and lunar dates
Resolve IANA time zone transitions
Check official UK bank holidays

Tools advertised by the last live check:

search_calculators
list_calculators
list_calculator_categories
list_working_day_calendars
get_calculator_schema
run_calculator
convert_units
list_units
calculate_business_deadline
check_china_working_day
add_china_working_days
count_china_working_days
check_uk_working_day
add_uk_working_days
count_uk_working_days
check_global_working_day
add_global_working_days
count_global_working_days
convert_solar_to_lunar
convert_lunar_to_solar
list_solar_terms
resolve_local_time
list_time_zone_transitions
convert_time_zone
calculate_loan_payment
compare_loans
check_global_public_holiday_working_day
add_global_public_holiday_working_days
count_global_public_holiday_working_days
check_global_reference_working_day
add_global_reference_working_days
count_global_reference_working_days
calculate_compound_interest
calculate_mortgage_payment
calculate_tip
calculate_amortization_schedule
calculate_bmi
calculate_bmr
calculate_tdee
calculate_running_pace
calculate_percentage
calculate_percentage_change
solve_quadratic_equation
calculate_fraction_arithmetic
calculate_circle_properties
calculate_descriptive_statistics
calculate_t_test
convert_temperature
calculate_kinetic_energy
solve_ohms_law
calculate_molar_mass
calculate_age
calculate_date_difference
check_singapore_working_day
add_singapore_working_days
count_singapore_working_days
check_australia_working_day
add_australia_working_days
count_australia_working_days
check_us_federal_working_day
add_us_federal_working_days
count_us_federal_working_days
check_canada_federal_working_day
add_canada_federal_working_days
count_canada_federal_working_days
check_japan_national_working_day
add_japan_national_working_days
count_japan_national_working_days
check_india_central_working_day
add_india_central_working_days
count_india_central_working_days
check_uae_federal_working_day
add_uae_federal_working_days
count_uae_federal_working_days
check_new_zealand_working_day
add_new_zealand_working_days
count_new_zealand_working_days
check_south_africa_working_day
add_south_africa_working_days
count_south_africa_working_days
check_ireland_working_day
add_ireland_working_days
count_ireland_working_days
check_fr_working_day
add_fr_working_days
count_fr_working_days
check_br_working_day
add_br_working_days
count_br_working_days
check_mx_working_day
add_mx_working_days
count_mx_working_days
check_ph_working_day
add_ph_working_days
count_ph_working_days
check_id_working_day
add_id_working_days
count_id_working_days
check_kr_working_day
add_kr_working_days
count_kr_working_days
check_it_working_day
add_it_working_days
count_it_working_days
check_es_working_day
add_es_working_days
count_es_working_days
check_de_working_day
add_de_working_days
count_de_working_days
check_nl_working_day
add_nl_working_days
count_nl_working_days
check_be_working_day
add_be_working_days
count_be_working_days
check_at_working_day
add_at_working_days
count_at_working_days
check_pl_working_day
add_pl_working_days
count_pl_working_days
check_pt_working_day
add_pt_working_days
count_pt_working_days
check_dk_working_day
add_dk_working_days
count_dk_working_days
check_se_working_day
add_se_working_days
count_se_working_days
check_no_working_day
add_no_working_days
count_no_working_days
check_fi_working_day
add_fi_working_days
count_fi_working_days
check_ch_working_day
add_ch_working_days
count_ch_working_days
check_tw_working_day
add_tw_working_days
count_tw_working_days
check_hk_working_day
add_hk_working_days
count_hk_working_days
check_turkey_working_day
add_turkey_working_days
count_turkey_working_days
check_sa_working_day
add_sa_working_days
count_sa_working_days
check_th_working_day
add_th_working_days
count_th_working_days
check_ar_working_day
add_ar_working_days
count_ar_working_days
check_uzbekistan_working_day
add_uzbekistan_working_days
count_uzbekistan_working_days
check_vn_working_day
add_vn_working_days
count_vn_working_days
check_bd_working_day
add_bd_working_days
count_bd_working_days
check_lk_working_day
add_lk_working_days
count_lk_working_days
check_ng_working_day
add_ng_working_days
count_ng_working_days
check_gh_working_day
add_gh_working_days
count_gh_working_days
check_pk_working_day
add_pk_working_days
count_pk_working_days
check_ke_working_day
add_ke_working_days
count_ke_working_days
check_eg_working_day
add_eg_working_days
count_eg_working_days
check_ru_working_day
add_ru_working_days
count_ru_working_days
check_co_working_day
add_co_working_days
count_co_working_days
check_my_working_day
add_my_working_days
count_my_working_days
check_cl_working_day
add_cl_working_days
count_cl_working_days
check_gr_working_day
add_gr_working_days
count_gr_working_days
check_kz_working_day
add_kz_working_days
count_kz_working_days
check_pe_working_day
add_pe_working_days
count_pe_working_days
check_sk_working_day
add_sk_working_days
count_sk_working_days
check_hu_working_day
add_hu_working_days
count_hu_working_days
check_cz_working_day
add_cz_working_days
count_cz_working_days
check_hr_working_day
add_hr_working_days
count_hr_working_days
check_si_working_day
add_si_working_days
count_si_working_days
check_ee_working_day
add_ee_working_days
count_ee_working_days
check_lu_working_day
add_lu_working_days
count_lu_working_days
check_mt_working_day
add_mt_working_days
count_mt_working_days
check_lt_working_day
add_lt_working_days
count_lt_working_days
check_lv_working_day
add_lv_working_days
count_lv_working_days
check_bg_working_day
add_bg_working_days
count_bg_working_days
check_ro_working_day
add_ro_working_days
count_ro_working_days
calculate_ab_test_significance
calculate_haversine_distance
price_black_scholes_option
calculate_subnet
estimate_ev_charging_time
calculate_depth_of_field
convert_betting_odds
find_chinese_zodiac
calculate_bazi_four_pillars
lookup_iching_hexagram
cast_plum_blossom_hexagram

Connect from your client

Each snippet registers the same endpoint; pick the client you use.

This server is operated by the named third party. Listing and endpoint checks are not an endorsement or a security audit. Review the operator's permissions, terms, and data handling before connecting. How listings are checked and corrected.

Claude Code

Run this once in a terminal. It registers a Streamable HTTP server. Use --scope project to write .mcp.json for the repo.

Claude Code configuration

claude mcp add --transport http calcgrid-mcp https://tttkmbb.com/mcp

Codex

Run this once. Codex stores MCP servers in ~/.codex/config.toml (or .codex/config.toml in a trusted project).

Codex configuration

codex mcp add calcgrid-mcp --url https://tttkmbb.com/mcp

Cursor

Merge this server into .cursor/mcp.json in your project, then enable calcgrid-mcp in your MCP settings.

Cursor configuration

{
  "mcpServers": {
    "calcgrid-mcp": {
      "url": "https://tttkmbb.com/mcp"
    }
  }
}

Cline

Merge this into cline_mcp_settings.json (Cline → MCP Servers → Configure). The type must be streamableHttp for a remote HTTP server.

Cline configuration

{
  "mcpServers": {
    "calcgrid-mcp": {
      "type": "streamableHttp",
      "url": "https://tttkmbb.com/mcp",
      "disabled": false
    }
  }
}

VS Code

Merge this server into .vscode/mcp.json. Use MCP: List Servers to start calcgrid-mcp and inspect its tools.

VS Code configuration

{
  "servers": {
    "calcgrid-mcp": {
      "type": "http",
      "url": "https://tttkmbb.com/mcp"
    }
  }
}

Gemini CLI

Run this once. It writes .gemini/settings.json in the current project; pass --scope user for ~/.gemini/settings.json.

Gemini CLI configuration

gemini mcp add --transport http calcgrid-mcp https://tttkmbb.com/mcp

Claude Desktop

Merge this into claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\), then restart Claude Desktop.

Claude Desktop configuration

{
  "mcpServers": {
    "calcgrid-mcp": {
      "url": "https://tttkmbb.com/mcp"
    }
  }
}

Windsurf

Merge this into ~/.codeium/windsurf/mcp_config.json, then refresh MCP in Cascade. Windsurf remote servers use serverUrl, not url.

Windsurf configuration

{
  "mcpServers": {
    "calcgrid-mcp": {
      "serverUrl": "https://tttkmbb.com/mcp"
    }
  }
}

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