🌙 Night Shift · Zero-Competition Tool
Night Shift Fasting Calculator
The only fasting calculator that correctly handles fasting windows crossing midnight. Built specifically for night workers, shift nurses, security staff, and frequent travelers.
Step 1 — Choose Your Protocol
16:8 is the most popular protocol — fast 16h, eat within 8h.
Step 2 — Personalise Your Schedule
Your eating window starts from this time
🎯 Your Goal
⏱ Fasting Stages
What Happens Inside Your Body
Live biological stages during your 16-hour fast — each backed by peer-reviewed research.
Last Meal Completed
+0hYour fasting clock starts now. Digestion begins and your body processes the glucose from your last meal.
📄 Mayo ClinicDigestion Phase
+2hBlood glucose peaks and insulin is released. Your body is actively digesting and storing nutrients from the last meal.
📄 NIH — Metabolism OverviewBlood Sugar Stabilizing
+4hInsulin levels begin to drop. Blood sugar returns toward baseline. Your body shifts from storing to maintaining.
📄 PubMed — Insulin & Glucose DynamicsGlycogen Depleting
+8hLiver glycogen stores are running low. Your body begins mobilising free fatty acids as an alternative fuel source.
📄 Cahill GF Jr — NEJM 1970🔥 Ketosis Begins
+12hGlycogen stores are nearly depleted. Your liver starts producing ketone bodies from fat — your brain switches to fat-burning mode.
📄 Cahill GF Jr — NEJM 1970✨ Autophagy Activates
+16hCellular housekeeping begins. Your cells start breaking down damaged proteins and organelles — a key anti-aging mechanism.
📄 Levine & Kroemer — Cell 2008* Biological timelines are approximate and vary by individual. Sources: PubMed, NIH, Cell journal.
Why Night-Shift Fasting Is Different
Most fasting apps and calculators assume a standard daytime schedule. If you work nights — starting your shift at 10 PM and sleeping until 2 PM — standard calculators give you nonsensical windows.
Our calculator includes a crossesMidnight detection flag that correctly calculates your eating and fasting windows regardless of when your day starts. Set your “eating start time” to whenever you wake up before your night shift.
💡 Night-Shift 16:8 Example
🕗 Wake up: 7:00 PM
🍽️ Eating window: 7:00 PM – 3:00 AM (8 hours)
🌙 Fasting window: 3:00 AM – 7:00 PM (16 hours, crosses midnight)
Medical Disclaimer
This tool provides estimates for informational purposes only. Always consult a licensed healthcare provider before beginning any fasting protocol — especially if you are pregnant, have a history of eating disorders, diabetes, or any other medical condition.
Sources: Mayo Clinic · NIH · PubMed