What This Calculator Measures
Recovery time between hard stretching or mobility sessions isn't fixed — it shifts with how hard and how long you trained, how sore you already are, and how well your sleep and hydration are supporting tissue repair. This calculator turns those five inputs into a planning estimate: a "recovery window" in hours before another demanding session is likely to be productive rather than counterproductive, a suggested mobility-minutes target for that window, and a 0-100 recovery score where higher means you're closer to ready. It works by adding up a "load" score from your workout duration, intensity, and current soreness, then subtracting a "support" score built from sleep, hydration, and any mobility work you're already doing.
Use it after an intense stretching, mobility, or flexibility-focused session to decide when to schedule the next one, or to see which single change — more sleep, more hydration, a lighter session — would shrink your recovery window the most. It is a planning heuristic built on fixed coefficients, not a physiological measurement of your actual tissue recovery, so treat the output as a starting point for scheduling, not a substitute for how your body actually feels on a given day.
The formula and its variables
Load = (Duration × 0.4) + (Intensity × 4) + (Soreness × 3); Support = (Sleep × 3.2) + (Hydration × 4) + (Mobility × 0.6); Recovery Window = clamp(Load − Support, 6, 96) hours; Recovery Score = 100 − Recovery Window.
- Workout Duration (min): length of the session that prompted the recovery estimate.
- Intensity Score (1-10): your perceived effort during that session.
- Soreness Level (1-10): how sore you feel right now, before the next session.
- Sleep Hours / Hydration (L) / Mobility Minutes: the three recovery-support inputs; each one directly reduces the estimated recovery window.
- Recovery Window: always kept between 6 and 96 hours regardless of inputs, since the model treats both extremely fast and extremely slow recovery as implausible beyond those bounds.
Worked example
With the default inputs — 55 min duration, intensity 7, soreness 5, 7.5 hours sleep, 2.5 L hydration, 12 mobility minutes — Load = (55 × 0.4) + (7 × 4) + (5 × 3) = 22 + 28 + 15 = 65. Support = (7.5 × 3.2) + (2.5 × 4) + (12 × 0.6) = 24 + 10 + 7.2 = 41.2. Recovery Window = 65 − 41.2 = 23.8 hrs, and Recovery Score = 100 − 23.8 = 76/100. The suggested mobility target is 8 + (7 × 1.5) + (5 × 2) = 8 + 10.5 + 10 = 28.5, rounded to 29 min. Raise sleep to 9 hours instead: Support becomes 9 × 3.2 + 10 + 7.2 = 28.8 + 17.2 = 46, dropping the window to 65 − 46 = 19 hrs — a reminder that sleep carries the heaviest single weight (3.2 per hour) among the three support inputs.
Interpretation guide
| Recovery Window | Meaning | Suggested Action |
|---|---|---|
| Under 16 hrs | Fast recovery | Light recovery needed; you can train again soon. |
| 16-30 hrs | Normal recovery | Standard recovery; the defaults map a balanced window. |
| 30-48 hrs | Elevated recovery need | Add mobility work and protect sleep before the next hard session. |
| 48+ hrs | Extended recovery | Prioritize rest, sleep, and hydration before training hard again. |
Common mistakes and how to interpret the result
- Understating your soreness level to get a shorter window. Since soreness is weighted at 3 points per unit, being honest about it matters more than optimism.
- Ignoring that sleep is the single heaviest support lever (3.2 points per hour) — cutting sleep on a recovery night undermines the window more than skipping mobility work does.
- Treating this as a hard cutoff instead of a planning guide. It doesn't measure actual muscle or connective tissue repair; use it alongside how your body actually feels.
- Forgetting the 6-96 hour clamp. Extreme inputs (very low intensity plus very high sleep and hydration) will still floor at 6 hours, and extreme load with poor support will cap at 96, not go below or above those bounds.