{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"barbell-plate-loading"},"result":{"entity_type":"calculator","id":"barbell-plate-loading","calculator_id":"barbell-plate-loading","canonical_url":"https://tttkmbb.com/fitness/barbell-plate-loading","name":"Barbell Plate Loading Calculator","title":"Barbell Plate Loading Calculator – Plates per Side for a Target Weight (kg or lb)","category":"fitness","category_name":"Sports & Fitness","tool_name":"calculate_barbell_plate_loading","featured_mcp_tool":false,"description":"Works out which plates to put on each side of a barbell to reach a target weight from the bar weight and the plate sizes available, loading the largest plates first, and reports the achievable weight and any shortfall.","use_when":"You have a target barbell weight and need the plate combination per side, or want the closest weight you can load with the plates you own.","do_not_use_when":"You want to estimate a one-rep max or training percentages (use one-rep-max) or a body-weight-adjusted strength score (use wilks-dots-score).","inputs":[{"name":"target_weight","label":"Target weight","type":"number","required":true,"max":2000,"exclusive_min":0,"description":"Total weight wanted on the bar, including the bar, in unit.","example":100},{"name":"unit","label":"Unit","type":"enum","required":false,"default":"kg","values":[{"value":"kg","label":"Kilograms (20 kg bar; 25/20/15/10/5/2.5/1.25 kg plates)","aliases":["kilograms","kilos"]},{"value":"lb","label":"Pounds (45 lb bar; 45/35/25/10/5/2.5 lb plates)","aliases":["lbs","pounds"]}],"description":"Unit of every weight; also selects the default bar weight and plate set.","example":"kg"},{"name":"bar_weight","label":"Bar weight","type":"number","required":false,"min":0,"max":100,"description":"Weight of the empty bar in unit. Defaults to 20 kg or 45 lb (standard Olympic bar); use 15 kg for a women's bar.","example":20},{"name":"available_plates","label":"Available plate sizes","type":"number_list","required":false,"description":"Plate sizes you can use (one plate, in unit), assumed available in unlimited pairs. Defaults to 25, 20, 15, 10, 5, 2.5, 1.25 kg or 45, 35, 25, 10, 5, 2.5 lb.","example":[25,20,15,10,5,2.5,1.25]}],"outputs":[{"name":"plates_per_side","label":"Plates per side","type":"list","decimals":3,"description":"Plate size and count for one side of the bar, largest first (plate, count)."},{"name":"plates_per_side_text","label":"Plates per side (text)","type":"string","decimals":4,"description":"The same loading as text, e.g. '25 + 15' or '2 × 45'."},{"name":"weight_per_side","label":"Weight per side","type":"number","decimals":3,"description":"(target_weight − bar_weight) / 2, in unit."},{"name":"loaded_weight","label":"Loaded weight","type":"number","decimals":3,"description":"Bar plus the plates actually loaded; equals target_weight when it is achievable."},{"name":"difference","label":"Difference","type":"number","decimals":3,"description":"loaded_weight − target_weight; zero or negative because the bar is never over-loaded."},{"name":"total_plates","label":"Total plates","type":"integer","decimals":4,"description":"Number of plates on both sides together."},{"name":"bar_weight","label":"Bar weight used","type":"number","decimals":2,"description":"Bar weight applied, in unit."}],"input_schema":{"type":"object","properties":{"target_weight":{"description":"Total weight wanted on the bar, including the bar, in unit.","type":"number","maximum":2000,"exclusiveMinimum":0,"examples":[100]},"unit":{"description":"Unit of every weight; also selects the default bar weight and plate set.","type":"string","enum":["kg","lb"],"default":"kg","examples":["kg"]},"bar_weight":{"description":"Weight of the empty bar in unit. Defaults to 20 kg or 45 lb (standard Olympic bar); use 15 kg for a women's bar.","type":"number","minimum":0,"maximum":100,"examples":[20]},"available_plates":{"description":"Plate sizes you can use (one plate, in unit), assumed available in unlimited pairs. Defaults to 25, 20, 15, 10, 5, 2.5, 1.25 kg or 45, 35, 25, 10, 5, 2.5 lb.","type":"array","items":{"type":"number"},"examples":[[25,20,15,10,5,2.5,1.25]]}},"additionalProperties":false,"required":["target_weight"]},"output_schema":{"type":"object","properties":{"plates_per_side":{"description":"Plate size and count for one side of the bar, largest first (plate, count).","type":"array"},"plates_per_side_text":{"description":"The same loading as text, e.g. '25 + 15' or '2 × 45'.","type":"string"},"weight_per_side":{"description":"(target_weight − bar_weight) / 2, in unit.","type":"number"},"loaded_weight":{"description":"Bar plus the plates actually loaded; equals target_weight when it is achievable.","type":"number"},"difference":{"description":"loaded_weight − target_weight; zero or negative because the bar is never over-loaded.","type":"number"},"total_plates":{"description":"Number of plates on both sides together.","type":"integer"},"bar_weight":{"description":"Bar weight applied, in unit.","type":"number"}}},"formula":"weight_per_side = (target_weight − bar_weight) / 2; for each plate size p from largest to smallest: count_p = floor(remaining / p), remaining −= count_p × p; loaded_weight = bar_weight + 2 × Σ count_p × p; difference = loaded_weight − target_weight","method":"Largest-first (greedy) loading matches how plates are racked and yields the exact combination with the fewest plates whenever each plate size is a multiple of the next smaller one, which holds for the standard kg and lb sets. Plates are assumed available in unlimited pairs; collars are not included.","sources":[{"name":"IPF Technical Rules Book (bar 20 kg; discs 25, 20, 15, 10, 5, 2.5, 1.25 kg)","url":"https://www.powerlifting.sport/rules/codes/info/technical-rules","type":"standard","retrieved_at":"2026-09-24"},{"name":"Wikipedia – Weight plate (standard Olympic plate denominations and bar weights)","url":"https://en.wikipedia.org/wiki/Weight_plate","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":"100 kg on a 20 kg bar","inputs":{"target_weight":100,"unit":"kg"},"expected":{"weight_per_side":40,"plates_per_side":[{"plate":25,"count":1},{"plate":15,"count":1}],"plates_per_side_text":"25 + 15","loaded_weight":100,"difference":0,"total_plates":4,"bar_weight":20},"url":"https://tttkmbb.com/api/v1/calculate/barbell-plate-loading?target_weight=100&unit=kg"},{"name":"225 lb on a 45 lb bar","inputs":{"target_weight":225,"unit":"lb"},"expected":{"weight_per_side":90,"plates_per_side":[{"plate":45,"count":2}],"plates_per_side_text":"2 × 45","loaded_weight":225,"difference":0,"total_plates":4,"bar_weight":45},"url":"https://tttkmbb.com/api/v1/calculate/barbell-plate-loading?target_weight=225&unit=lb"}],"faq":[{"q":"Does the target include the bar?","a":"Yes. target_weight is the total on the bar; the calculator subtracts bar_weight before splitting the rest between the two sides."},{"q":"What if the weight cannot be made exactly?","a":"The nearest lower weight is loaded and difference shows the shortfall (e.g. 102 kg with 1.25 kg smallest plates loads 100 kg, difference −2). Add smaller change plates to available_plates to close the gap."},{"q":"Can I use a 15 kg women's bar or a 35 lb bar?","a":"Yes: set bar_weight explicitly; unit only changes the defaults."}],"tags":["barbell plate calculator","plates per side","plate loading","barbell weight","olympic bar 20 kg","45 lb bar"],"related":[{"calculator_id":"one-rep-max","reason":"Estimate the maximum and training percentages that set the target weight."},{"calculator_id":"wilks-dots-score","reason":"Score the lift relative to body weight."},{"calculator_id":"mass","reason":"Convert plate weights between kilograms and pounds."}],"links":{"html":"https://tttkmbb.com/fitness/barbell-plate-loading","markdown":"https://tttkmbb.com/fitness/barbell-plate-loading.md","json":"https://tttkmbb.com/fitness/barbell-plate-loading.json","api":"https://tttkmbb.com/api/v1/calculate/barbell-plate-loading","schema":"https://tttkmbb.com/api/v1/calculators/barbell-plate-loading","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:49:41Z","next_actions":[{"tool":"run_calculator","calculator_id":"barbell-plate-loading","reason":"Run Barbell Plate Loading Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/fitness/barbell-plate-loading.md"}}