TSS Calculator (Training Stress Score for Cycling)

What this tool does

TSS was devised by Dr Andrew Coggan and Hunter Allen to give a ride a single number: exactly one hour at your FTP scores 100. It multiplies duration by intensity squared, so a ride at 70 % of FTP earns only about 49 points an hour. Use normalized power, not average power: NP is a weighted average (a 30-second rolling average raised to the fourth power) that counts surges more, so a variable ride costs more than its average suggests. As a rough guide, under about 150 is a light day, 150–300 usually recovered by the next day, 300–450 leaves some fatigue, and over 450 can take several days. The score is only as good as your FTP, so retest it every few weeks.

Formula

IF = NP ÷ FTP · TSS = (seconds × NP × IF) ÷ (FTP × 3600) × 100

Variables

Worked example

Limitations

• This tool is informational only. It does not diagnose, treat or replace a qualified health professional. Speak to a doctor before making decisions about your health.
• The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.