Health Calculators
Sleep Restriction Therapy Calculator
This calculator helps estimate an appropriate sleep window using Sleep Restriction Therapy (SRT), a core component of Cognitive Behavioral Therapy for Insomnia (CBT-I). It is an educational estimate, not personal medical advice.
Diary entries for your last N nights. Add earlier nights for a broader average.
How Sleep Restriction Therapy Works
SRT limits time in bed (TIB) to better match your average sleep time, which can increase sleep drive and sleep efficiency. The initial window is max(average total sleep time, safety floor), rounded up to the nearest 5 minutes. Each week, TIB is adjusted by sleep efficiency: extend by 15 min if it is at least 85%, restrict by 15 min if below 80%, and hold if it is 80-85%.
About This Calculator
What It Does
This sleep restriction therapy calculator uses your recent sleep data to estimate a practical sleep window. It calculates bedtime from your fixed wake time, average sleep duration, selected variant, and safety floor. The goal is to consolidate sleep and improve sleep efficiency over time.
Worked Example
If your average total sleep time is 5 hours 42 minutes (342 min) and your fixed wake time is 7:00 AM, the Standard variant rounds the recommendation up to 345 min (5 hr 45 min). Bedtime = 7:00 AM - 5 hr 45 min = 1:15 AM.
Real-World Usage
A person with chronic insomnia who averages 5 hours of sleep but spends 8 hours in bed might use this calculator to set a careful first sleep window. After a week, they recalculate: if efficiency exceeds 85%, the window extends by 15 minutes. If below 80%, it restricts further.
Local Context
In Germany, CBT-I methods are used in behavioural insomnia support. This calculator keeps the SRT protocol consistent while using German country context and dot-separated date display.
This calculator provides educational information only. It is not a substitute for professional medical advice, diagnosis, or treatment. Sleep restriction therapy can increase daytime sleepiness and may not be suitable for everyone.
Frequently Asked Questions
Is this medical advice?
No. This calculator provides educational estimates based on published SRT protocols. It is not personal medical advice. Stop or choose a gentler setting if daytime sleepiness becomes a problem. Be especially careful with bipolar disorder, seizure disorders, untreated sleep apnea, or safety-critical work.
What if the formula output is below 5.5 hours?
The default safety floor is 5.5 hours. You can adjust this in advanced settings, but lower floors may increase daytime sleepiness and should be used with extra caution.
What is sleep compression?
Sleep compression gradually reduces time in bed over several weeks rather than making an abrupt restriction. The default plan is 6 weeks. Each week is calculated from the difference between your current time in bed and the target.
How often should I recalculate?
SRT is commonly reviewed weekly using the past week of sleep data. After one week at the new window, use Recalculating mode with your new diary and current time in bed.
Can I exclude an unusual night from my diary?
Yes. Use Exclude for nights that were not representative, such as illness, travel, or unusual circumstances. Excluded nights are not counted in the average.