Water Intake Calculator
Estimate daily fluid needs from official intakes plus exercise.
Sleep Calculator
Bedtimes and wake-up times based on 90-minute sleep cycles.
About these tools
The Water Intake Calculator is based on National Academies adequate intakes with an exercise allowance, and the Sleep Calculator plans bedtimes around 90-minute cycles while keeping the AASM recommendation of 7 or more hours in view. Both are general guides; people with heart or kidney conditions, sleep disorders or other medical needs should follow their clinician's advice.
Hydration basics
The National Academies set adequate intakes for total water — from drinks and food — of about 3.7 liters a day for men and 2.7 liters for women. Most healthy people meet their needs by drinking with meals and when thirsty. Needs rise with heat, altitude, exercise, pregnancy and breastfeeding, and fall for people told by a doctor to restrict fluids. Pale yellow urine is a simple everyday check.
Sleep basics
Adults need seven or more hours of sleep a night, according to the American Academy of Sleep Medicine and Sleep Research Society. Regular short sleep is linked with weight gain, high blood pressure, diabetes, depression and accidents. A consistent wake-up time, morning daylight, a cool and dark bedroom, and limiting late caffeine and alcohol all help.
Small habits, big effects
Hydration and sleep affect energy, appetite, mood and exercise performance. Rather than chasing exact numbers, use these tools to set a reasonable target, then adjust based on how you feel. Persistent tiredness despite enough sleep, loud snoring, or extreme thirst are worth discussing with a doctor.
Water, sleep and exercise
Hydration and sleep both affect training. Even mild dehydration can make exercise feel harder, and short sleep reduces endurance and reaction time. If you train regularly, plan fluids around sessions — the water calculator adds an exercise allowance — and protect a consistent sleep window, especially before hard workouts or races. For people managing weight, sleep matters too: short sleep is associated with increased appetite and cravings.
Privacy
As with every SimpleFitCalc tool, nothing you enter is stored or sent anywhere.
When to get help
Speak to a doctor about ongoing insomnia, loud snoring with pauses in breathing, excessive daytime sleepiness, unusual thirst or frequent urination. These can be signs of conditions such as sleep apnea or diabetes that benefit from proper assessment and treatment.
Both calculators take under a minute: enter your sex and typical exercise for a daily fluid estimate, or a bedtime or wake-up time for a sleep plan built around full cycles.
The calculators in detail
Water Intake Calculator
Estimates how much to drink each day from the National Academies adequate intake for total water, plus an allowance for exercise, shown in liters, ounces and cups.
Sleep Calculator
Suggests bedtimes or wake-up times based on roughly 90-minute sleep cycles and the time you take to fall asleep, while highlighting the AASM recommendation of at least seven hours for adults.
Frequently asked questions
How much water should I drink?
The National Academies adequate intake for total water is about 3.7 L for men and 2.7 L for women, including water from food.
How much sleep do adults need?
The AASM and Sleep Research Society recommend 7 or more hours per night for adults.
Are 90-minute sleep cycles exact?
No. Cycles average about 90 minutes but vary; total sleep matters more.
Who should not rely on these estimates?
People with heart, kidney or sleep disorders, or who are pregnant, should follow their clinician's advice.
Estimates for general information only — not medical advice. See our Terms & Medical Disclaimer.