A good daily target for many healthy adults is about 91 oz for women and 125 oz for men of total water from all drinks and food combined. If you want a simple rule of thumb, aim for about 64–128 oz of fluids a day , then adjust for heat, exercise, and thirst.

Quick scoop

The common “8 glasses a day” idea is a rough shortcut, not a hard rule. A better guide is to drink enough that you usually feel well-hydrated and your urine stays pale yellow rather than dark.

What changes your needs

  • Hot weather and heavy sweating mean you need more.
  • Exercise increases fluid loss, so drink more before, during, and after activity.
  • Illness like fever, vomiting, or diarrhea can raise your needs.
  • Pregnancy and breastfeeding also increase fluid needs.

Easy check

A practical approach is to keep water nearby and drink when thirsty, rather than forcing a fixed number every day. If you’re active, in a hot climate, or noticing signs of dehydration like dry mouth, dizziness, or darker urine, you probably need more.

Simple answer in ounces

  • Most women: about 91 oz/day total fluid.
  • Most men: about 125 oz/day total fluid.
  • Basic everyday target: roughly 64–128 oz/day , depending on your body and activity.

TL;DR: for most people, start around 90–125 oz a day , then increase if you sweat a lot or it’s hot.