{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"vertical-jump-power"},"result":{"entity_type":"calculator","id":"vertical-jump-power","calculator_id":"vertical-jump-power","canonical_url":"https://tttkmbb.com/fitness/vertical-jump-power","name":"Vertical Jump Power Calculator","title":"Vertical Jump Power Calculator – Peak Power from Jump Height and Body Mass (Sayers, Harman, Lewis)","category":"fitness","category_name":"Sports & Fitness","tool_name":"estimate_vertical_jump_power","featured_mcp_tool":false,"description":"Estimates lower-body power from a vertical jump height and body mass with the Sayers peak-power equation (60.7·height + 45.3·mass − 2055), the Harman peak-power equation and the Lewis average-power formula, plus take-off velocity and flight time.","use_when":"You have a measured vertical jump (jump-and-reach or countermovement jump height) and body mass and want an estimate of peak or average muscular power in watts.","do_not_use_when":"Force-plate power data are available (they measure power directly), or you need strength rather than power (use one-rep-max).","inputs":[{"name":"jump_height_cm","label":"Jump height","type":"number","unit":"cm","required":true,"min":10,"max":150,"description":"Vertical jump height: jump-and-reach difference or countermovement-jump rise of the centre of mass.","example":50},{"name":"body_mass_kg","label":"Body mass","type":"number","unit":"kg","required":true,"min":30,"max":300,"description":"Body mass in kilograms (the equations were fitted to adults).","example":75}],"outputs":[{"name":"sayers_peak_power_w","label":"Peak power (Sayers)","type":"number","unit":"W","decimals":0,"description":"60.7 × jump_height_cm + 45.3 × body_mass_kg − 2055 (recommended equation)."},{"name":"harman_peak_power_w","label":"Peak power (Harman)","type":"number","unit":"W","decimals":0,"description":"61.9 × jump_height_cm + 36.0 × body_mass_kg − 1822."},{"name":"lewis_average_power_w","label":"Average power (Lewis)","type":"number","unit":"W","decimals":0,"description":"√4.9 × body_mass_kg × √(jump_height_m) × 9.81; underestimates true power and is kept for comparison with older norms."},{"name":"relative_peak_power_w_per_kg","label":"Relative peak power","type":"number","unit":"W/kg","decimals":2,"description":"Sayers peak power divided by body mass."},{"name":"takeoff_velocity_m_per_s","label":"Take-off velocity","type":"number","unit":"m/s","decimals":2,"description":"√(2 × g × height) with g = 9.80665 m/s²."},{"name":"flight_time_s","label":"Flight time","type":"number","unit":"s","decimals":3,"description":"2 × takeoff_velocity / g (symmetric flight)."}],"input_schema":{"type":"object","properties":{"jump_height_cm":{"description":"Vertical jump height: jump-and-reach difference or countermovement-jump rise of the centre of mass. Unit: cm.","type":"number","minimum":10,"maximum":150,"examples":[50],"x-unit":"cm"},"body_mass_kg":{"description":"Body mass in kilograms (the equations were fitted to adults). Unit: kg.","type":"number","minimum":30,"maximum":300,"examples":[75],"x-unit":"kg"}},"additionalProperties":false,"required":["jump_height_cm","body_mass_kg"]},"output_schema":{"type":"object","properties":{"sayers_peak_power_w":{"description":"60.7 × jump_height_cm + 45.3 × body_mass_kg − 2055 (recommended equation). Unit: W.","type":"number","x-unit":"W"},"harman_peak_power_w":{"description":"61.9 × jump_height_cm + 36.0 × body_mass_kg − 1822. Unit: W.","type":"number","x-unit":"W"},"lewis_average_power_w":{"description":"√4.9 × body_mass_kg × √(jump_height_m) × 9.81; underestimates true power and is kept for comparison with older norms. Unit: W.","type":"number","x-unit":"W"},"relative_peak_power_w_per_kg":{"description":"Sayers peak power divided by body mass. Unit: W/kg.","type":"number","x-unit":"W/kg"},"takeoff_velocity_m_per_s":{"description":"√(2 × g × height) with g = 9.80665 m/s². Unit: m/s.","type":"number","x-unit":"m/s"},"flight_time_s":{"description":"2 × takeoff_velocity / g (symmetric flight). Unit: s.","type":"number","x-unit":"s"}}},"formula":"Sayers: P_peak = 60.7·h_cm + 45.3·m_kg − 2055; Harman: P_peak = 61.9·h_cm + 36.0·m_kg − 1822; Lewis: P_avg = √4.9 × m_kg × √(h_cm/100) × 9.81; v_takeoff = √(2·g·h); t_flight = 2·v_takeoff / g","method":"Sayers et al. (1999) derived the equation on 108 college athletes and non-athletes from squat-jump heights against force-plate peak power (SEE ≈ 355 W) and found separate equations for men and women unnecessary; applied to countermovement-jump heights it over-estimates by about 2.7 %. Harman (1991) and Lewis are older estimates included for comparison.","sources":[{"name":"Sayers SP, Harackiewicz DV, Harman EA, Frykman PN, Rosenstein MT (1999) Cross-validation of three jump power equations, Med Sci Sports Exerc 31:572-577","url":"https://pubmed.ncbi.nlm.nih.gov/10211854/","type":"peer_reviewed","retrieved_at":"2026-09-24"},{"name":"Topend Sports – Vertical jump power calculators (Lewis, Harman, Sayers formulas)","url":"https://www.topendsports.com/testing/vertical-jump-power.htm","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":"50 cm jump, 75 kg","inputs":{"jump_height_cm":50,"body_mass_kg":75},"expected":{"sayers_peak_power_w":4378,"harman_peak_power_w":3973,"lewis_average_power_w":1152,"relative_peak_power_w_per_kg":58.37,"takeoff_velocity_m_per_s":3.13,"flight_time_s":0.639},"url":"https://tttkmbb.com/api/v1/calculate/vertical-jump-power?jump_height_cm=50&body_mass_kg=75"},{"name":"30 cm jump, 60 kg","inputs":{"jump_height_cm":30,"body_mass_kg":60},"expected":{"sayers_peak_power_w":2484,"harman_peak_power_w":2195,"lewis_average_power_w":714,"relative_peak_power_w_per_kg":41.4,"takeoff_velocity_m_per_s":2.43,"flight_time_s":0.495},"url":"https://tttkmbb.com/api/v1/calculate/vertical-jump-power?jump_height_cm=30&body_mass_kg=60"}],"faq":[{"q":"Why is the Lewis value so much lower?","a":"The Lewis nomogram estimates average power during the push-off and ignores body-mass displacement before take-off; Sayers found it under-estimates force-plate peak power by roughly 70 %. Use Sayers for peak power."},{"q":"Which jump height should I enter?","a":"Jump-and-reach (standing reach subtracted) or a countermovement jump measured by a mat or app. Heights from arm-swing jumps are higher and inflate the estimate."}],"tags":["vertical jump power","sayers formula","lewis formula","peak power watts","jump height to power","countermovement jump"],"related":[{"calculator_id":"one-rep-max","reason":"Maximal strength estimate for the same athlete."},{"calculator_id":"free-fall","reason":"Flight time and velocity for any drop or rise height."},{"calculator_id":"kinetic-energy","reason":"Energy at take-off from mass and velocity."}],"links":{"html":"https://tttkmbb.com/fitness/vertical-jump-power","markdown":"https://tttkmbb.com/fitness/vertical-jump-power.md","json":"https://tttkmbb.com/fitness/vertical-jump-power.json","api":"https://tttkmbb.com/api/v1/calculate/vertical-jump-power","schema":"https://tttkmbb.com/api/v1/calculators/vertical-jump-power","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:50:28Z"}