{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"simple-interest"},"result":{"entity_type":"calculator","id":"simple-interest","calculator_id":"simple-interest","canonical_url":"https://tttkmbb.com/finance/simple-interest","name":"Simple Interest Calculator","title":"Simple Interest Calculator – Interest and Total Amount from Principal, Rate and Time","category":"finance","category_name":"Finance","tool_name":"calculate_simple_interest","featured_mcp_tool":false,"description":"Computes interest that accrues only on the original principal (no compounding) over a term in years, and the resulting total amount.","use_when":"The agreement states simple, non-compounding interest, e.g. short-term personal loans, some bonds and statutory interest on late payments, or you want a quick estimate.","do_not_use_when":"Interest is reinvested or charged on accrued interest (use compound-interest), or you need the level payment of an amortizing loan (use loan-payment).","inputs":[{"name":"principal","label":"Principal","type":"number","required":true,"min":0,"max":1000000000000,"description":"Amount lent, borrowed or deposited.","example":1000},{"name":"annual_rate_percent","label":"Annual interest rate","type":"number","unit":"%","required":true,"min":0,"max":1000,"description":"Simple annual rate in percent; 5 means 5 %.","example":5},{"name":"years","label":"Time","type":"number","unit":"years","required":true,"min":0,"max":200,"description":"Term in years; fractional values allowed (6 months = 0.5, 90 days = 90/365 ≈ 0.2466).","example":3}],"outputs":[{"name":"interest","label":"Interest","type":"number","decimals":2,"description":"Total simple interest over the term."},{"name":"total_amount","label":"Total amount","type":"number","decimals":2,"description":"Principal plus interest."},{"name":"interest_per_year","label":"Interest per year","type":"number","decimals":2,"description":"principal × rate, the constant yearly interest."},{"name":"interest_per_month","label":"Interest per month","type":"number","decimals":2,"description":"interest_per_year / 12."}],"input_schema":{"type":"object","properties":{"principal":{"description":"Amount lent, borrowed or deposited.","type":"number","minimum":0,"maximum":1000000000000,"examples":[1000]},"annual_rate_percent":{"description":"Simple annual rate in percent; 5 means 5 %. Unit: %.","type":"number","minimum":0,"maximum":1000,"examples":[5],"x-unit":"%"},"years":{"description":"Term in years; fractional values allowed (6 months = 0.5, 90 days = 90/365 ≈ 0.2466). Unit: years.","type":"number","minimum":0,"maximum":200,"examples":[3],"x-unit":"years"}},"additionalProperties":false,"required":["principal","annual_rate_percent","years"]},"output_schema":{"type":"object","properties":{"interest":{"description":"Total simple interest over the term.","type":"number"},"total_amount":{"description":"Principal plus interest.","type":"number"},"interest_per_year":{"description":"principal × rate, the constant yearly interest.","type":"number"},"interest_per_month":{"description":"interest_per_year / 12.","type":"number"}}},"formula":"interest = principal × (annual_rate_percent / 100) × years; total_amount = principal + interest","sources":[{"name":"Investopedia – Simple Interest: Who Benefits, With Formula and Example","url":"https://www.investopedia.com/terms/s/simple_interest.asp","type":"reference","retrieved_at":"2026-09-23"},{"name":"Wikipedia – Interest (simple interest)","url":"https://en.wikipedia.org/wiki/Interest","type":"reference","retrieved_at":"2026-09-23"}],"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":"1,000 at 5 % for 3 years","inputs":{"principal":1000,"annual_rate_percent":5,"years":3},"expected":{"interest":150,"total_amount":1150,"interest_per_year":50,"interest_per_month":4.17},"url":"https://tttkmbb.com/api/v1/calculate/simple-interest?principal=1000&annual_rate_percent=5&years=3"},{"name":"25,000 at 4.5 % for 2.5 years","inputs":{"principal":25000,"annual_rate_percent":4.5,"years":2.5},"expected":{"interest":2812.5,"total_amount":27812.5},"url":"https://tttkmbb.com/api/v1/calculate/simple-interest?principal=25000&annual_rate_percent=4.5&years=2.5"}],"faq":[{"q":"How do I enter a term in months or days?","a":"Convert to years: months / 12, days / 365 (or / 360 if the contract uses a 360-day banker's year). Example: 18 months = 1.5 years."},{"q":"How does simple interest compare with compound interest?","a":"Simple interest grows linearly; compound interest grows exponentially because earned interest also earns interest. Over one period at annual compounding they are equal; over longer terms compounding yields more."}],"tags":["simple interest","interest calculator","principal rate time","prt formula"],"related":[{"calculator_id":"compound-interest","reason":"Interest on interest at a chosen compounding frequency."},{"calculator_id":"loan-payment","reason":"Level monthly payment on an amortizing loan."}],"links":{"html":"https://tttkmbb.com/finance/simple-interest","markdown":"https://tttkmbb.com/finance/simple-interest.md","json":"https://tttkmbb.com/finance/simple-interest.json","api":"https://tttkmbb.com/api/v1/calculate/simple-interest","schema":"https://tttkmbb.com/api/v1/calculators/simple-interest","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-23"},"timestamp":"2026-09-23T23:24:37Z"}