{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"rent-split"},"result":{"entity_type":"calculator","id":"rent-split","calculator_id":"rent-split","canonical_url":"https://tttkmbb.com/everyday/rent-split","name":"Rent Split Calculator","title":"Rent Split Calculator – Share Rent Equally, by Room Area or by Income","category":"everyday","category_name":"Everyday Life","tool_name":"split_rent","featured_mcp_tool":false,"description":"Splits a total rent between housemates equally, in proportion to each person's room area (optionally dividing the common-area share equally) or in proportion to incomes, and returns per-person shares rounded to cents that add up exactly to the total.","use_when":"Several people share a flat or house and need a defensible split of the rent by room size or income instead of a plain equal split.","do_not_use_when":"You are splitting a one-off bill with a tip (use bill-split) or need utilities split by metered usage; this tool does not track deposits or running shared expenses.","inputs":[{"name":"total_rent","label":"Total rent","type":"number","required":true,"min":0,"max":100000000,"description":"Total rent per period, in your currency.","example":3000},{"name":"method","label":"Method","type":"enum","required":false,"default":"equal","values":[{"value":"equal","label":"Equal shares","aliases":["even","evenly","same"]},{"value":"by_room_area","label":"Proportional to room area","aliases":["room","area","by_area","by_room_size","room_size","square_meters"]},{"value":"by_income","label":"Proportional to income","aliases":["income","proportional_to_income","salary"]}],"description":"How to divide the rent.","example":"by_room_area"},{"name":"people","label":"Number of people","type":"integer","required":false,"min":1,"max":100,"description":"Number of tenants for the equal method (otherwise taken from the length of room_areas or incomes).","example":3},{"name":"room_areas","label":"Room areas","type":"number_list","required":false,"description":"Private room area per person in any one unit (m² or ft²), in tenant order; required for by_room_area.","example":[12,15,18]},{"name":"incomes","label":"Incomes","type":"number_list","required":false,"description":"Income per person (same period and currency for everyone), in tenant order; required for by_income.","example":[40000,50000,60000]},{"name":"common_area","label":"Common area","type":"number","required":false,"default":0,"min":0,"max":1000000,"description":"Shared space (kitchen, living room, bathrooms) in the same unit as room_areas; used by by_room_area.","example":0},{"name":"common_area_share_equal","label":"Split common-area rent equally","type":"boolean","required":false,"default":true,"description":"true: the rent attributable to common_area is divided equally and only the private-room rent follows room size; false: the whole rent follows private room size.","example":true}],"outputs":[{"name":"shares","label":"Shares","type":"number_list","decimals":2,"description":"Rent per person in list order, rounded to cents so that they sum to total_rent."},{"name":"shares_table","label":"Shares table","type":"list","decimals":2,"description":"Per person: person, share, percent of the total and the weight used (1, room area or income)."},{"name":"per_person_average","label":"Average per person","type":"number","decimals":2,"description":"total_rent / number of people."},{"name":"people_count","label":"People","type":"integer","decimals":4,"description":"Number of shares."},{"name":"largest_share","label":"Largest share","type":"number","decimals":2,"description":"Highest individual share."},{"name":"smallest_share","label":"Smallest share","type":"number","decimals":2,"description":"Lowest individual share."},{"name":"method_used","label":"Method","type":"string","decimals":4,"description":"Description of the split that was applied."}],"input_schema":{"type":"object","properties":{"total_rent":{"description":"Total rent per period, in your currency.","type":"number","minimum":0,"maximum":100000000,"examples":[3000]},"method":{"description":"How to divide the rent.","type":"string","enum":["equal","by_room_area","by_income"],"default":"equal","examples":["by_room_area"]},"people":{"description":"Number of tenants for the equal method (otherwise taken from the length of room_areas or incomes).","type":"integer","minimum":1,"maximum":100,"examples":[3]},"room_areas":{"description":"Private room area per person in any one unit (m² or ft²), in tenant order; required for by_room_area.","type":"array","items":{"type":"number"},"minItems":1,"examples":[[12,15,18]]},"incomes":{"description":"Income per person (same period and currency for everyone), in tenant order; required for by_income.","type":"array","items":{"type":"number"},"minItems":1,"examples":[[40000,50000,60000]]},"common_area":{"description":"Shared space (kitchen, living room, bathrooms) in the same unit as room_areas; used by by_room_area.","type":"number","minimum":0,"maximum":1000000,"default":0,"examples":[0]},"common_area_share_equal":{"description":"true: the rent attributable to common_area is divided equally and only the private-room rent follows room size; false: the whole rent follows private room size.","type":"boolean","default":true,"examples":[true]}},"additionalProperties":false,"required":["total_rent"]},"output_schema":{"type":"object","properties":{"shares":{"description":"Rent per person in list order, rounded to cents so that they sum to total_rent.","type":"array","items":{"type":"number"}},"shares_table":{"description":"Per person: person, share, percent of the total and the weight used (1, room area or income).","type":"array"},"per_person_average":{"description":"total_rent / number of people.","type":"number"},"people_count":{"description":"Number of shares.","type":"integer"},"largest_share":{"description":"Highest individual share.","type":"number"},"smallest_share":{"description":"Lowest individual share.","type":"number"},"method_used":{"description":"Description of the split that was applied.","type":"string"}}},"formula":"equal: share_i = total_rent / n; by_income: share_i = total_rent × income_i / Σ incomes; by_room_area: common_rent = total_rent × common_area / (Σ areas + common_area) when common_area_share_equal else 0, share_i = common_rent / n + (total_rent − common_rent) × area_i / Σ areas; shares are rounded to cents with the largest-remainder method so that Σ share_i = total_rent","method":"Proportional splits assume the rent scales with the chosen weight; the mixed rule (common-area rent shared equally, private rent by area) is the usual compromise for flats with unequal rooms. Percentages are shares of the total; fairness schemes based on bids (rental harmony) are not implemented.","sources":[{"name":"Rental harmony – fair division of rent between housemates (Wikipedia)","url":"https://en.wikipedia.org/wiki/Rental_harmony","type":"reference","retrieved_at":"2026-09-24"},{"name":"Largest remainder method – rounding shares so they sum to the total (Wikipedia)","url":"https://en.wikipedia.org/wiki/Largest_remainder_method","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":"3000 by room area 12 / 15 / 18","inputs":{"total_rent":3000,"method":"by_room_area","room_areas":[12,15,18]},"expected":{"shares":[800,1000,1200],"per_person_average":1000,"people_count":3,"largest_share":1200,"smallest_share":800},"url":"https://tttkmbb.com/api/v1/calculate/rent-split?total_rent=3000&method=by_room_area&room_areas=12%2C15%2C18"},{"name":"3000 by income 40,000 / 60,000","inputs":{"total_rent":3000,"method":"by_income","incomes":[40000,60000]},"expected":{"shares":[1200,1800],"per_person_average":1500,"people_count":2},"url":"https://tttkmbb.com/api/v1/calculate/rent-split?total_rent=3000&method=by_income&incomes=40000%2C60000"}],"faq":[{"q":"How is the common area handled?","a":"With common_area_share_equal (default) the fraction of rent that corresponds to the shared space is split equally, and only the remainder follows room size: 3000 with rooms 12/15/18 m² and 30 m² of common space gives 880 / 1000 / 1120."},{"q":"Why do the shares not equal total / people exactly?","a":"Shares are rounded to whole cents; the largest-remainder method assigns the leftover cents to the people with the largest fractional parts so the shares still add up to the total."}],"tags":["rent split calculator","split rent by room size","split rent by income","roommate rent calculator","fair rent share"],"related":[{"calculator_id":"bill-split","reason":"Equal split of a bill with an optional tip."},{"calculator_id":"unit-price","reason":"Compare cost per square metre between flats."}],"links":{"html":"https://tttkmbb.com/everyday/rent-split","markdown":"https://tttkmbb.com/everyday/rent-split.md","json":"https://tttkmbb.com/everyday/rent-split.json","api":"https://tttkmbb.com/api/v1/calculate/rent-split","schema":"https://tttkmbb.com/api/v1/calculators/rent-split","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T03:44:12Z"}