Daily Water Intake Calculator
Find out how much water to drink per day based on your weight (35 ml per kg), with optional extra for your minutes of exercise.
How the water goal is calculated
The baseline is the rule of 35 ml per kg of body weight — the same one Fitney uses as the default goal when a client does not yet have a water goal set on their meal plan. Without a weight, the reference is 2,000 ml per day.
If you enter your minutes of exercise, we add roughly 500 ml per hour of training. That extra is an approximate general guideline, not medical advice: heat, intensity and how much you sweat change your needs a lot.
The result is shown in ml, liters and 250 ml glasses to make it easy to follow. If you coach clients, you can set the water goal right on the meal plan — see how to set a hydration goal and track it in the app.
Frequently asked questions
How much water should I drink per day?
A widely used rule of thumb is 35 ml per kg of body weight. Someone who weighs 70 kg (about 154 lb), for example, lands at roughly 2.45 liters a day. It is a general guideline: heat, sweat, training, pregnancy and health conditions all change what you need.
Should I drink more on training days?
Yes. As an approximate general guideline, add about 500 ml for each hour of exercise, spread before, during and after the workout. Long sessions, hot weather or heavy sweating can call for more.
Does this calculator replace advice from a dietitian?
No. It gives a general estimate and is not medical advice. People with kidney or heart disease, or on a fluid restriction, should follow the goal set by their doctor or nutritionist.
Water goal on the meal plan, logging in the app
Set the water goal alongside the meal plan. Clients log it with one tap in the app and get hydration reminders. 14-day free trial.