{ "id": "ftp", "version": "23d33f88aa0a", "status": "published", "name": "FTP Calculator", "question": "What is my FTP?", "summary": "Estimates cycling functional threshold power (FTP) as 95% of a 20-minute test, with watts per kilogram and the seven power training levels in watts.", "category": "sports", "subcategory": "fitness", "url": "https://www.acalculator.org/sports/ftp-calculator", "markdown": "https://www.acalculator.org/sports/ftp-calculator.md", "kind": "function", "method": "FTP = 0.95 × 20-minute average power; each level’s edges = FTP × its percent, rounded to whole watts.", "assumptions": [ "The 20-minute test is an all-out, evenly paced effort after a warm-up; 95% of it estimates the power you could hold for about an hour.", "Levels follow the TrainingPeaks table as published, including its 1-point gaps (55% to 56%, 75% to 76% and so on).", "1 lb = 0.45359237 kg exactly." ], "inputs": { "$schema": "https://json-schema.org/draft/2020-12/schema", "type": "object", "properties": { "m": { "title": "I have", "description": "A 20-minute test result to estimate FTP from, or an FTP you already know.", "type": "string", "enum": [ "test", "ftp" ] }, "p20": { "title": "20-minute average power (W)", "description": "The average power of an all-out 20-minute effort, in watts.", "type": "number", "minimum": 1, "maximum": 3000 }, "ftp": { "title": "FTP (W)", "description": "Your functional threshold power in watts.", "type": "number", "minimum": 1, "maximum": 3000 }, "u": { "title": "Weight in", "description": "Kilograms or pounds for your body weight.", "type": "string", "enum": [ "kg", "lb" ] }, "wt": { "title": "Body weight (kg)", "description": "Your body weight in kilograms, for watts per kilogram. Leave it empty to skip.", "type": "number", "minimum": 1, "maximum": 1000 }, "wtlb": { "title": "Body weight (lb)", "description": "Your body weight in pounds, for watts per kilogram. Leave it empty to skip.", "type": "number", "minimum": 1, "maximum": 2200 } } }, "outputs": { "ftpW": { "label": "FTP", "description": "Functional threshold power: 95% of the 20-minute power, or the FTP you typed.", "format": "number" }, "wkg": { "label": "Watts per kilogram", "description": "FTP ÷ body weight in kilograms.", "format": "number" }, "z1": { "label": "Level 1: Active recovery", "description": "Active recovery: under 55% of FTP, in watts.", "format": "text" }, "z2": { "label": "Level 2: Endurance", "description": "Endurance: 56% to 75% of FTP, in watts.", "format": "text" }, "z3": { "label": "Level 3: Tempo", "description": "Tempo: 76% to 90% of FTP, in watts.", "format": "text" }, "z4": { "label": "Level 4: Lactate threshold", "description": "Lactate threshold: 91% to 105% of FTP, in watts.", "format": "text" }, "z5": { "label": "Level 5: VO2 max", "description": "VO2 max: 106% to 120% of FTP, in watts.", "format": "text" }, "z6": { "label": "Level 6: Anaerobic capacity", "description": "Anaerobic capacity: 121% and above of FTP, in watts.", "format": "text" }, "z7": { "label": "Level 7: Neuromuscular power", "description": "Neuromuscular power: no set percent of FTP, in watts.", "format": "text" } }, "defaultAnswer": { "inputs": { "m": "test", "p20": 250, "ftp": 240, "u": "kg", "wt": 75, "wtlb": 165 }, "outputs": { "ftpW": 237.5, "wkg": 3.1666666666666665, "z1": "up to 131 W", "z2": "133–178 W", "z3": "181–214 W", "z4": "216–249 W", "z5": "252–285 W", "z6": "287 W and up", "z7": "Short maximal sprints" }, "text": "Your FTP is 237.5 W." }, "examples": [ { "given": { "m": "test", "p20": 250, "u": "kg", "wt": 75 }, "expect": { "ftpW": 237.5, "wkg": 3.1666666666666665, "z1": "up to 131 W", "z2": "133–178 W", "z3": "181–214 W", "z4": "216–249 W", "z5": "252–285 W", "z6": "287 W and up" }, "source": "hand calculation in content.mdx: 250 × 0.95 = 237.5; 237.5 × 0.55 = 130.625 → 131; 0.56 → 133, 0.75 → 178.125 → 178; Python 3: Fraction; TrainingPeaks Help Center, How to Calculate Threshold Values for Power, Heart Rate or Pace (FTP = 95% of the best 20-minute power), https://help.trainingpeaks.com/hc/en-us/articles/204071934-How-to-Calculate-Threshold-Values-for-Power-Heart-Rate-or-Pace; TrainingPeaks, Power Training Levels (levels 1 to 7 as % of threshold power), https://www.trainingpeaks.com/blog/power-training-levels/" }, { "given": { "m": "ftp", "ftp": 200, "u": "lb", "wtlb": 150 }, "expect": { "ftpW": 200, "wkg": 2.939496829131701, "z1": "up to 110 W", "z4": "182–210 W", "z6": "242 W and up" }, "source": "hand calculation in content.mdx: 150 lb = 68.0388555 kg; 200 ÷ 68.0388555 = 2.9395; Python 3: Fraction; 200 × 0.91 = 182, × 1.05 = 210; NIST SP 811 (1 lb = 0.45359237 kg); TrainingPeaks, Power Training Levels (levels 1 to 7 as % of threshold power), https://www.trainingpeaks.com/blog/power-training-levels/" }, { "given": { "m": "test", "p20": 300, "u": "kg" }, "expect": { "ftpW": 285, "z2": "160–214 W", "z5": "302–342 W" }, "source": "hand calculation in content.mdx: 300 × 0.95 = 285; 285 × 0.56 = 159.6 → 160; × 0.75 = 213.75 → 214; × 1.06 = 302.1 → 302; × 1.2 = 342; TrainingPeaks, Power Training Levels (levels 1 to 7 as % of threshold power), https://www.trainingpeaks.com/blog/power-training-levels/" } ], "sources": [ "TrainingPeaks Help Center, How to Calculate Threshold Values for Power, Heart Rate or Pace (multiply the best recent 20-minute power by 95%). https://help.trainingpeaks.com/hc/en-us/articles/204071934-How-to-Calculate-Threshold-Values-for-Power-Heart-Rate-or-Pace (retrieved 2026-10-19)", "TrainingPeaks, Power Training Levels (Coggan levels 1 to 7 as % of threshold power). https://www.trainingpeaks.com/blog/power-training-levels/ (retrieved 2026-10-19)", "NIST Special Publication 811 (2008), Appendix B.8: 1 lb = 0.45359237 kg exactly. https://www.nist.gov/pml/special-publication-811 (retrieved 2026-10-19)" ], "related": [ "vo2-max", "rpe" ], "changelog": [] }