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FTP Power Zones Calculator

Converts a cyclist's functional threshold power (FTP) into Andrew Coggan's seven power training levels (active recovery to neuromuscular power) as watt ranges, and reports power-to-weight in W/kg when body weight is given.

When to use

You know an FTP from a 20-minute or ramp test and need watt targets for each training zone, or want the W/kg figure for comparison.

Do not use when: You train by heart rate rather than power (use heart-rate-zones), or you need running/rowing intensity zones (use vdot-training-paces or rowing-split).

Formula

low_watts = ftp_watts × lower_percent / 100; high_watts = ftp_watts × upper_percent / 100 with Coggan levels: 1 active recovery < 55 %, 2 endurance 56–75 %, 3 tempo 76–90 %, 4 lactate threshold 91–105 %, 5 VO2max 106–120 %, 6 anaerobic capacity 121–150 %, 7 neuromuscular power > 150 %; ftp_w_per_kg = ftp_watts / weight_kg

Levels follow Coggan's power training levels (Allen & Coggan, Training and Racing with a Power Meter). Coggan's original table lists level 6 as > 121 % and level 7 as 'not applicable' (short maximal sprints); the 150 % split used here is the common convention in training software. Zone boundaries are guides, not physiological thresholds measured for the individual.

Inputs

Parameter	Type	Unit	Required	Description
`ftp_watts`	number	W	yes	Functional threshold power: the highest power sustainable for about an hour (commonly 95 % of a 20-minute all-out test). Range: ≥ 30, ≤ 800
`weight_kg`	number	kg	no	Optional rider weight, used only to report W/kg. Range: > 0, ≤ 300

Outputs

Output	Type	Unit	Description
`zones`	list		Seven rows: zone, name, percent_of_ftp, low_watts, high_watts (null for zone 7, which has no upper bound).
`threshold_zone_watts`	string		Watt range of the lactate-threshold zone (91–105 % of FTP) as text.
`ftp_w_per_kg`	number	W/kg	ftp_watts / weight_kg (only when weight_kg is given).

Example

FTP 250 W, 70 kg: {"ftp_watts":250,"weight_kg":70} → {"zones":[{"zone":1,"low_watts":0,"high_watts":138},{"zone":2,"low_watts":140,"high_watts":188},{"zone":3,"low_watts":190,"high_watts":225},{"zone":4,"low_watts":228,"high_watts":263},{"zone":5,"low_watts":265,"high_watts":300},{"zone":6,"low_watts":303,"high_watts":375},{"zone":7,"low_watts":375,"high_watts":null}],"threshold_zone_watts":"228–263 W","ftp_w_per_kg":3.57}

FTP 300 W: {"ftp_watts":300} → {"zones":[{"zone":1,"high_watts":165},{"zone":2,"low_watts":168,"high_watts":225},{"zone":3,"low_watts":228,"high_watts":270},{"zone":4,"low_watts":273,"high_watts":315},{"zone":5,"low_watts":318,"high_watts":360},{"zone":6,"low_watts":363,"high_watts":450},{"zone":7,"low_watts":450}],"threshold_zone_watts":"273–315 W"}

GET https://tttkmbb.com/api/v1/calculate/ftp-power-zones?ftp_watts=250&weight_kg=70

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/ftp-power-zones (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/ftp-power-zones · Markdown: https://tttkmbb.com/fitness/ftp-power-zones.md · JSON definition: https://tttkmbb.com/fitness/ftp-power-zones.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="ftp-power-zones"
OpenAPI operationId: calculate_ftp_power_zones
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

FAQ

How do I get my FTP?

Most riders take 95 % of the average power of a 20-minute all-out effort after a thorough warm-up, or use a ramp test (about 75 % of the best 1-minute power). A 60-minute test measures it directly.

Why are the zone boundaries not contiguous (55 % then 56 %)?

They reproduce Coggan's published integer percentages; in practice a rider at 55.5 % of FTP is at the top of zone 1 / bottom of zone 2.

Related calculators

Heart Rate Zone Calculator — Heart-rate based training zones for the same rider.
Bike Gear Ratio Calculator — Gearing and speed for a given cadence.
Calories Burned Calculator — Energy expenditure of the ride.