{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"discount"},"result":{"entity_type":"calculator","id":"discount","calculator_id":"discount","canonical_url":"https://tttkmbb.com/finance/discount","name":"Discount Calculator","title":"Discount Calculator – Sale Price, Amount Saved and Stacked Discounts","category":"finance","category_name":"Finance","tool_name":"calculate_discount","featured_mcp_tool":false,"description":"Computes the final price and amount saved after a percentage discount, an optional second discount applied to the reduced price, and optional sales tax on the result.","use_when":"You want the sale price after a percent-off promotion, the effective rate of two stacked discounts (e.g. 20 % off plus an extra 10 %), or the checkout price with tax.","do_not_use_when":"You know the original and sale prices and need the percentage off (use percentage-change), or the discount is a fixed amount rather than a percent (just subtract it).","inputs":[{"name":"original_price","label":"Original price","type":"number","required":true,"min":0,"max":1000000000,"description":"List price before any discount.","example":80},{"name":"discount_percent","label":"Discount","type":"number","unit":"%","required":true,"min":0,"max":100,"description":"First percentage off the original price.","example":25},{"name":"second_discount_percent","label":"Additional discount","type":"number","unit":"%","required":false,"default":0,"min":0,"max":100,"description":"Optional extra percent off applied to the already-discounted price (stacked, not added).","example":0},{"name":"tax_percent","label":"Sales tax","type":"number","unit":"%","required":false,"default":0,"min":0,"max":100,"description":"Optional sales tax or VAT applied to the final discounted price.","example":0}],"outputs":[{"name":"final_price","label":"Final price","type":"number","decimals":2,"description":"Price after all discounts, before tax."},{"name":"amount_saved","label":"You save","type":"number","decimals":2,"description":"original_price − final_price."},{"name":"effective_discount_percent","label":"Effective discount","type":"number","unit":"%","decimals":2,"description":"Combined percentage off the original price."},{"name":"price_after_first_discount","label":"Price after first discount","type":"number","decimals":2,"description":"original_price × (1 − discount_percent/100)."},{"name":"final_price_with_tax","label":"Final price with tax","type":"number","decimals":2,"description":"final_price × (1 + tax_percent/100)."}],"input_schema":{"type":"object","properties":{"original_price":{"description":"List price before any discount.","type":"number","minimum":0,"maximum":1000000000,"examples":[80]},"discount_percent":{"description":"First percentage off the original price. Unit: %.","type":"number","minimum":0,"maximum":100,"examples":[25],"x-unit":"%"},"second_discount_percent":{"description":"Optional extra percent off applied to the already-discounted price (stacked, not added). Unit: %.","type":"number","minimum":0,"maximum":100,"default":0,"examples":[0],"x-unit":"%"},"tax_percent":{"description":"Optional sales tax or VAT applied to the final discounted price. Unit: %.","type":"number","minimum":0,"maximum":100,"default":0,"examples":[0],"x-unit":"%"}},"additionalProperties":false,"required":["original_price","discount_percent"]},"output_schema":{"type":"object","properties":{"final_price":{"description":"Price after all discounts, before tax.","type":"number"},"amount_saved":{"description":"original_price − final_price.","type":"number"},"effective_discount_percent":{"description":"Combined percentage off the original price. Unit: %.","type":"number","x-unit":"%"},"price_after_first_discount":{"description":"original_price × (1 − discount_percent/100).","type":"number"},"final_price_with_tax":{"description":"final_price × (1 + tax_percent/100).","type":"number"}}},"formula":"final_price = original_price × (1 − discount_percent/100) × (1 − second_discount_percent/100); amount_saved = original_price − final_price; effective_discount = amount_saved / original_price × 100; final_price_with_tax = final_price × (1 + tax_percent/100)","sources":[{"name":"Wikipedia – Discounts and allowances","url":"https://en.wikipedia.org/wiki/Discounts_and_allowances","type":"reference","retrieved_at":"2026-09-23"},{"name":"Wikipedia – Percentage","url":"https://en.wikipedia.org/wiki/Percentage","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":"80 at 25 % off","inputs":{"original_price":80,"discount_percent":25},"expected":{"final_price":60,"amount_saved":20,"effective_discount_percent":25,"final_price_with_tax":60},"url":"https://tttkmbb.com/api/v1/calculate/discount?original_price=80&discount_percent=25"},{"name":"200 at 20 % off plus extra 10 %, 8 % tax","inputs":{"original_price":200,"discount_percent":20,"second_discount_percent":10,"tax_percent":8},"expected":{"final_price":144,"amount_saved":56,"effective_discount_percent":28,"price_after_first_discount":160,"final_price_with_tax":155.52},"url":"https://tttkmbb.com/api/v1/calculate/discount?original_price=200&discount_percent=20&second_discount_percent=10&tax_percent=8"}],"faq":[{"q":"Is 20 % off plus 10 % off the same as 30 % off?","a":"No. The second discount applies to the reduced price, so the combined discount is 1 − 0.8 × 0.9 = 28 %, not 30 %."},{"q":"Is tax charged on the discounted price?","a":"In most jurisdictions store discounts reduce the taxable amount, so tax is applied to final_price; manufacturer coupons are sometimes taxed on the pre-coupon price."}],"tags":["discount calculator","percent off","sale price","double discount","how much do i save"],"related":[{"calculator_id":"percentage","reason":"General percent-of and percent-off arithmetic."},{"calculator_id":"sales-tax","reason":"Add or extract sales tax on its own."}],"links":{"html":"https://tttkmbb.com/finance/discount","markdown":"https://tttkmbb.com/finance/discount.md","json":"https://tttkmbb.com/finance/discount.json","api":"https://tttkmbb.com/api/v1/calculate/discount","schema":"https://tttkmbb.com/api/v1/calculators/discount","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-23"},"timestamp":"2026-09-23T23:25:42Z","next_actions":[{"tool":"run_calculator","calculator_id":"discount","reason":"Run Discount Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/finance/discount.md"}}