{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"budget-50-30-20"},"result":{"entity_type":"calculator","id":"budget-50-30-20","calculator_id":"budget-50-30-20","canonical_url":"https://tttkmbb.com/finance/budget-50-30-20","name":"50/30/20 Budget Calculator","title":"50/30/20 Budget Calculator – Needs, Wants and Savings Split of After-Tax Income","category":"finance","category_name":"Finance","tool_name":"calculate_50_30_20_budget","featured_mcp_tool":false,"description":"Splits monthly after-tax income into needs, wants and savings/debt repayment with the 50/30/20 rule (Warren & Tyagi, All Your Worth, 2005) or custom percentages, and compares the targets with current spending when it is given.","use_when":"You want target amounts for essentials, discretionary spending and savings from take-home pay, or to check how far current spending deviates from the 50/30/20 split.","do_not_use_when":"You need the time or deposit to reach a savings target (use savings-goal), a debt payoff schedule (use debt-payoff), or a line-item budget. Informational; not financial advice.","inputs":[{"name":"monthly_after_tax_income","label":"Monthly after-tax income","type":"number","required":true,"max":1000000000,"exclusive_min":0,"description":"Take-home pay per month after income tax and payroll deductions (add back retirement contributions withheld at source if you count them as savings).","example":4000},{"name":"needs_percent","label":"Needs share","type":"number","unit":"%","required":false,"default":50,"min":0,"max":100,"description":"Share for essentials: housing, utilities, groceries, insurance, minimum debt payments, transport to work.","example":50},{"name":"wants_percent","label":"Wants share","type":"number","unit":"%","required":false,"default":30,"min":0,"max":100,"description":"Share for discretionary spending: dining out, entertainment, travel, subscriptions.","example":30},{"name":"savings_percent","label":"Savings share","type":"number","unit":"%","required":false,"default":20,"min":0,"max":100,"description":"Share for savings, investments and debt repayment beyond the minimums. The three shares must sum to 100.","example":20},{"name":"current_needs","label":"Current needs spending (optional)","type":"number","required":false,"min":0,"max":1000000000,"description":"What you currently spend on needs per month, for comparison.","example":2100},{"name":"current_wants","label":"Current wants spending (optional)","type":"number","required":false,"min":0,"max":1000000000,"description":"Current monthly discretionary spending.","example":1300},{"name":"current_savings","label":"Current savings (optional)","type":"number","required":false,"min":0,"max":1000000000,"description":"Current monthly savings and extra debt repayment.","example":600}],"outputs":[{"name":"needs_budget","label":"Needs budget","type":"number","decimals":2,"description":"monthly_after_tax_income × needs_percent / 100."},{"name":"wants_budget","label":"Wants budget","type":"number","decimals":2,"description":"monthly_after_tax_income × wants_percent / 100."},{"name":"savings_budget","label":"Savings target","type":"number","decimals":2,"description":"monthly_after_tax_income × savings_percent / 100."},{"name":"annual_savings","label":"Annual savings at target","type":"number","decimals":2,"description":"savings_budget × 12."},{"name":"needs_difference","label":"Needs: budget − current","type":"number","decimals":2,"description":"needs_budget − current_needs (positive = under budget; only when current_needs is given)."},{"name":"wants_difference","label":"Wants: budget − current","type":"number","decimals":2,"description":"wants_budget − current_wants (positive = under budget; only when current_wants is given)."},{"name":"savings_difference","label":"Savings: target − current","type":"number","decimals":2,"description":"savings_budget − current_savings (positive = saving less than the target, i.e. a shortfall; only when current_savings is given)."},{"name":"current_needs_percent","label":"Current needs share","type":"number","unit":"%","decimals":2,"description":"current_needs / income × 100 (when given)."},{"name":"current_wants_percent","label":"Current wants share","type":"number","unit":"%","decimals":2,"description":"current_wants / income × 100 (when given)."},{"name":"current_savings_percent","label":"Current savings share","type":"number","unit":"%","decimals":2,"description":"current_savings / income × 100 (when given)."},{"name":"assessment","label":"Assessment","type":"string","decimals":4,"description":"Plain-language comparison of current spending with the targets."}],"input_schema":{"type":"object","properties":{"monthly_after_tax_income":{"description":"Take-home pay per month after income tax and payroll deductions (add back retirement contributions withheld at source if you count them as savings).","type":"number","maximum":1000000000,"exclusiveMinimum":0,"examples":[4000]},"needs_percent":{"description":"Share for essentials: housing, utilities, groceries, insurance, minimum debt payments, transport to work. Unit: %.","type":"number","minimum":0,"maximum":100,"default":50,"examples":[50],"x-unit":"%"},"wants_percent":{"description":"Share for discretionary spending: dining out, entertainment, travel, subscriptions. Unit: %.","type":"number","minimum":0,"maximum":100,"default":30,"examples":[30],"x-unit":"%"},"savings_percent":{"description":"Share for savings, investments and debt repayment beyond the minimums. The three shares must sum to 100. Unit: %.","type":"number","minimum":0,"maximum":100,"default":20,"examples":[20],"x-unit":"%"},"current_needs":{"description":"What you currently spend on needs per month, for comparison.","type":"number","minimum":0,"maximum":1000000000,"examples":[2100]},"current_wants":{"description":"Current monthly discretionary spending.","type":"number","minimum":0,"maximum":1000000000,"examples":[1300]},"current_savings":{"description":"Current monthly savings and extra debt repayment.","type":"number","minimum":0,"maximum":1000000000,"examples":[600]}},"additionalProperties":false,"required":["monthly_after_tax_income"]},"output_schema":{"type":"object","properties":{"needs_budget":{"description":"monthly_after_tax_income × needs_percent / 100.","type":"number"},"wants_budget":{"description":"monthly_after_tax_income × wants_percent / 100.","type":"number"},"savings_budget":{"description":"monthly_after_tax_income × savings_percent / 100.","type":"number"},"annual_savings":{"description":"savings_budget × 12.","type":"number"},"needs_difference":{"description":"needs_budget − current_needs (positive = under budget; only when current_needs is given).","type":"number"},"wants_difference":{"description":"wants_budget − current_wants (positive = under budget; only when current_wants is given).","type":"number"},"savings_difference":{"description":"savings_budget − current_savings (positive = saving less than the target, i.e. a shortfall; only when current_savings is given).","type":"number"},"current_needs_percent":{"description":"current_needs / income × 100 (when given). Unit: %.","type":"number","x-unit":"%"},"current_wants_percent":{"description":"current_wants / income × 100 (when given). Unit: %.","type":"number","x-unit":"%"},"current_savings_percent":{"description":"current_savings / income × 100 (when given). Unit: %.","type":"number","x-unit":"%"},"assessment":{"description":"Plain-language comparison of current spending with the targets.","type":"string"}}},"formula":"needs_budget = income × needs_percent/100; wants_budget = income × wants_percent/100; savings_budget = income × savings_percent/100; annual_savings = savings_budget × 12; x_difference = x_budget − current_x; current_x_percent = current_x / income × 100","method":"The 50/30/20 rule from Warren & Tyagi's All Your Worth (2005) applies to after-tax income and treats minimum debt payments as needs and extra repayments as savings; it is a rule of thumb, not a prescription, and custom percentages (e.g. 60/20/20 in high-cost cities) are accepted as long as they sum to 100.","sources":[{"name":"Warren E. & Tyagi A. W. (2005) All Your Worth: The Ultimate Lifetime Money Plan, Free Press","url":"https://www.simonandschuster.com/books/All-Your-Worth/Elizabeth-Warren/A-Guide-to-Personal-Finances/9780743269889","type":"textbook","retrieved_at":"2026-09-24"},{"name":"Investopedia – The 50/30/20 Budget Rule Explained With Examples","url":"https://www.investopedia.com/ask/answers/022916/what-502030-budget-rule.asp","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"4,000 take-home per month, default 50/30/20","inputs":{"monthly_after_tax_income":4000},"expected":{"needs_budget":2000,"wants_budget":1200,"savings_budget":800,"annual_savings":9600},"url":"https://tttkmbb.com/api/v1/calculate/budget-50-30-20?monthly_after_tax_income=4000"},{"name":"6,500 per month, currently spending 3,500 / 1,800 and saving 1,200","inputs":{"monthly_after_tax_income":6500,"current_needs":3500,"current_wants":1800,"current_savings":1200},"expected":{"needs_budget":3250,"wants_budget":1950,"savings_budget":1300,"annual_savings":15600,"needs_difference":-250,"wants_difference":150,"savings_difference":100,"current_needs_percent":53.85},"url":"https://tttkmbb.com/api/v1/calculate/budget-50-30-20?monthly_after_tax_income=6500&current_needs=3500&current_wants=1800&current_savings=1200"}],"faq":[{"q":"Is the income before or after tax?","a":"After tax (take-home pay). The rule was defined on after-tax income; if retirement contributions are deducted from your paycheck before you see it, add them back to income and count them as savings."},{"q":"Where do debt payments go?","a":"Minimum required payments are needs (they are not optional); anything paid above the minimum counts toward the 20 % savings/debt-repayment share."},{"q":"What if my needs exceed 50 %?","a":"Common where housing is expensive. Adjust the shares (e.g. 60/20/20) to keep the savings share, or treat the excess as a signal to lower fixed costs; the rule is a guideline, not a requirement."}],"tags":["50/30/20 rule","50 30 20 budget","budget calculator","needs wants savings","take home pay budget","monthly budget"],"related":[{"calculator_id":"savings-goal","reason":"Turn the savings target into a timeline for a specific goal."},{"calculator_id":"debt-payoff","reason":"Apply the savings share to clear a balance faster."},{"calculator_id":"salary-converter","reason":"Convert an annual salary into monthly pay before budgeting."}],"links":{"html":"https://tttkmbb.com/finance/budget-50-30-20","markdown":"https://tttkmbb.com/finance/budget-50-30-20.md","json":"https://tttkmbb.com/finance/budget-50-30-20.json","api":"https://tttkmbb.com/api/v1/calculate/budget-50-30-20","schema":"https://tttkmbb.com/api/v1/calculators/budget-50-30-20","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T03:49:08Z"}