Free MCP servers that give Claude, ChatGPT, Cursor and VS Code facts a model cannot know on its own. New tax rules, live prices and levels, exact calendar arithmetic. No API key and no sign-up.

server	tools	hosted URL
cups-to-grams-mcp	convert_ingredient, search_ingredients, scale_recipe, convert_oven_temperature	`https://cups-to-grams-mcp.lipmichal.workers.dev/mcp`
dscr-loan-calculator-mcp	calculate_dscr, max_loan_for_target_dscr, rent_needed_for_target_dscr, compare_scenarios, amortization_summary	`https://dscr-loan-calculator-mcp.lipmichal.workers.dev/mcp`
gold-price-per-gram-mcp	get_gold_price_per_gram, get_metal_prices, calculate_jewelry_value, convert_gold_units	`https://gold-price-per-gram-mcp.lipmichal.workers.dev/mcp`
lake-level-mcp	search_lakes, get_lake_level, get_lake_history, compare_lakes	`https://lake-level-mcp.lipmichal.workers.dev/mcp`
minimum-wage-mcp	get_minimum_wage, list_upcoming_increases, compare_states, annual_income_at_minimum_wage	`https://minimum-wage-mcp.lipmichal.workers.dev/mcp`
no-tax-on-overtime-mcp	calculate_overtime_deduction, calculate_tips_deduction, calculate_senior_deduction, estimate_tax_savings, explain_eligibility	`https://no-tax-on-overtime-mcp.lipmichal.workers.dev/mcp`
paycheck-calculator-mcp	calculate_take_home_pay, compare_states_take_home, salary_to_hourly, hourly_to_salary, get_federal_tax_brackets	`https://paycheck-calculator-mcp.lipmichal.workers.dev/mcp`
uk-income-tax-salary-mcp	calculate_uk_take_home, get_uk_tax_bands, compare_salaries, marginal_rate_at_income	`https://uk-income-tax-salary-mcp.lipmichal.workers.dev/mcp`
us-federal-holidays-business-days-mcp	list_federal_holidays, is_business_day, add_business_days, count_business_days, invoice_due_date	`https://us-federal-holidays-business-days-mcp.lipmichal.workers.dev/mcp`

Paste the hosted URL into Claude (Settings, Connectors, Add custom connector) or ChatGPT (developer mode, new connector). For Claude Desktop, Cursor or VS Code, each README has the one-line npx -y github:theluckystrike/<name> install.