Sleep Calculator
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Free online sleep calculator: find the best bedtime or wake-up time using sleep cycle science. Based on the 90-minute sleep cycle principle, this calculator helps you wake up at the optimal point between cycles so you feel refreshed and alert, not groggy. Enter what time you need to wake up to see recommended bedtimes, or enter when you plan to go to bed to see optimal wake-up times. Includes time to fall asleep adjustment. Perfect for improving sleep quality, managing jet lag, and establishing healthy sleep routines. Mac OS 9 retro style. No signup required.

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Tools|Sleep|hello-tools 2026

Calorie Calculator - BMR, TDEE, BMI & Macro Calculator - Free Online

Free online calorie calculator: calculate BMR (Basal Metabolic Rate), TDEE (Total Daily Energy Expenditure), BMI, and macronutrients (protein, carbs, fat) for weight loss, weight maintenance or muscle gain. Uses Mifflin-St Jeor equation. Mac OS 9 retro style.

Free online tool. hello-tools offers free, easy-to-use web tools. Calculators, converters, generators, and more — all in Mac OS 9 retro style. No signup required, no data stored.