Acute:Chronic Workload Ratio Calculator (ACWR for Training Load)
Your acute:chronic workload ratio from four weeks of training load, with its zone, the largest sensible load for next week and the week-on-week change.
Results
What this tool does
The acute:chronic workload ratio divides the load of the last week by the average of the last four, using any consistent measure such as session RPE × minutes, TSS, kilometres or hours. Tim Gabbett's 2016 paper linked ratios of about 0.8 to 1.3 with the lowest injury risk in team sports and 1.5 or more with the highest, which is how the sweet spot and danger zone came about. The idea is useful as a reminder not to ramp up too fast, but it has real critics: the maths of the coupled version can create the pattern by itself, and the thresholds are not universal. Treat it as a prompt to look at your progression, not a predictor of injury.
Formula
ACWR = this week's load ÷ average load of the last 4 weeks · next week's cap for ACWR ≤ 1.3: x = 1.3 × (last 3 weeks) ÷ 2.7
Variables
| Symbol | Meaning | Unit |
|---|---|---|
l1 | Training load this week (the last 7 days) | — |
l2 | Training load last week | — |
l3 | Training load two weeks ago | — |
l4 | Training load three weeks ago | — |
AC | Acute:chronic workload ratio (ACWR) | — |
CH | Chronic load (4-week average) | — |
ZN | Zone | — |
NX | Largest load next week that keeps the ratio at 1.3 or below | — |
WC | Change from last week | % |
Worked example
- Training load this week (the last 7 days)400
- Training load last week380
- Training load two weeks ago350
- Training load three weeks ago330
- Acute:chronic workload ratio (ACWR)1.10
- Chronic load (4-week average)365
- Zone0.8 to 1.3 — the so-called sweet spot
- Largest load next week that keeps the ratio at 1.3 or below544
- Change from last week5 %
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 default values are typical reference figures, not measurements of your situation. Replace them with your own data whenever you have it.