Are You In Ketosis?
Add Your Numbers And Find Out!
Our free Ketone Level Estimator is the first online ketosis calculator that predicts your blood ketone level (β-hydroxybutyrate, mmol/L) with science-driven accuracy—no finger-prick required. Enter your fasting hours, daily carbs, exercise, sleep, weight, keto experience and gender; in seconds you’ll know if you’re in nutritional ketosis and how deep.
The algorithm combines data from classic starvation research (Cahill, 2006), modern ketogenic-diet trials (Volek & Phinney, 2012; Paoli et al., 2013) and studies on aerobic training and sex differences in ketone production (White et al., 2018). It accounts for the three biggest levers: longer fasting raises β-HB linearly, carb intake stalls ketosis logarithmically, and each hour of moderate exercise adds more mmol/L in fasted athletes.
Unlike generic macro calculators, this tool adjusts for body weight, sleep quality and whether you’re new to keto—factors proven to shift ketone output through glycogen size, cortisol and metabolic adaptation. It also applies a small sex-specific offset; research shows women often reach slightly higher ketone peaks after a fast of equal length.
Use the result to fine-tune your ketogenic lifestyle: extend a fast, trim carbs, add a brisk walk, or improve sleep to nudge your ketone reading upward. A value ≥0.5 mmol/L signals you’ve crossed into nutritional ketosis; 1–3 mmol/L is the “optimal ketosis” zone cherished by weight-loss and cognitive-performance enthusiasts. Deeper levels may occur in multi-day fasts but are rarely needed for routine fat burning.
This Keto Level estimator is designed for healthy adults following a ketogenic diet; if you manage diabetes or suspect ketoacidosis, check real blood values and consult a healthcare professional.