Your Inputs
glasses/day

Including water, herbal tea, and other low-sugar drinks

Activity Level affects fluid needs
Climate / Environment

Used to estimate dehydration's concentration effect on your current reading

Your Hydration Assessment

Enter your daily water intake and body weight above to see your personalised hydration assessment.

How This Works

Your recommended daily water intake is calculated from body weight, adjusted for activity level and climate:

Target (ml) = Weight(kg) x base_ml_per_kg + activity_add + climate_add

Base: 30ml/kg. Activity adds: Moderate +300ml, Active +600ml. Climate adds: Hot +300ml, Very Hot +600ml.

The blood glucose concentration effect is based on the principle that dehydration reduces plasma volume, concentrating glucose in the bloodstream. When intake falls below 50% of target, blood glucose readings may be elevated by 20-40 mg/dL due to haemoconcentration alone - not actual metabolic change.

Note: 1 glass = 250ml. Coffee, tea, broth, and fruit/vegetables also contribute to hydration but are not accounted for in this simplified calculator.

Why Hydration Matters in Diabetes

Dehydration and blood sugar affect each other in a cycle that can quickly escalate:

  • Dehydration reduces plasma volume, concentrating glucose - blood readings rise even without eating more
  • High blood glucose causes osmotic diuresis - the kidneys excrete more water to remove glucose, worsening dehydration
  • This cycle is a key driver of diabetic ketoacidosis (DKA) - dehydration accelerates ketone accumulation
  • Hyperglycaemia episodes frequently involve some degree of dehydration, even without obvious thirst
  • Thirst is an unreliable early indicator - significant dehydration can occur before thirst is felt, especially in older adults
Practical Tips for Better Hydration
  • Start each morning with a large glass (500ml) before coffee or breakfast
  • Keep a visible water bottle at your desk, bedside, and in your car
  • Set hourly reminders on your phone or CGM device if possible
  • Herbal teas, sparkling water, and diluted low-sugar drinks all count
  • Eat high-water foods: cucumber, celery, melon, zucchini, tomatoes
  • If blood glucose is elevated unexpectedly - drink a large glass of water first before correcting with insulin
! Medical Disclaimer
This calculator is for educational and informational purposes only. Hydration recommendations are general guidelines and may not account for individual medical conditions (e.g. kidney disease, heart failure, diuretic medications) that significantly affect fluid requirements. The blood glucose concentration effect shown is an estimate - do not use it to adjust insulin doses. Always consult your healthcare provider about fluid intake guidelines specific to your condition.