Reviewed by Emily Carter, MSc, RD
Registered Dietitian & Hydration Research Specialist. Emily holds a Master of Science in Human Nutrition and has spent over a decade translating nutrition research into practical, evidence-based guidance for everyday health and athletic performance.
How Much Water a Day in Litres: Quick Answer
The formula: body weight (kg) × 0.035 = litres per day. A 70kg adult needs 2.45L as a daily baseline. Add 0.5L per 30 minutes of exercise. Add 0.5L in hot weather. The common "2 litres a day" recommendation is approximately right for a 57kg sedentary adult — but most Canadians need 2.5–3L+ from drinks on active days.
Your Daily Litre Target: The Formula
Step 1 — Find your baseline:
Body weight (kg) × 0.035 = litres/day
| Your Weight | Daily Baseline |
|---|---|
| 50 kg | 1.75L |
| 55 kg | 1.93L |
| 60 kg | 2.1L |
| 65 kg | 2.28L |
| 70 kg | 2.45L |
| 75 kg | 2.63L |
| 80 kg | 2.8L |
| 85 kg | 2.98L |
| 90 kg | 3.15L |
| 100 kg | 3.5L |
Step 2 — Add for exercise: +0.5L per 30 minutes of moderate to vigorous activity
Step 3 — Add for environment:
| +0.5L in hot weather (25°C+) | +0.5L during air travel |
|---|
Step 4 — Special conditions:
| +0.7L breastfeeding |
|---|
Worked Examples
65kg woman, office job, no exercise today: 65 × 0.035 = 2.28L
80kg man, 60-minute gym session, summer: 80 × 0.035 = 2.8L + 1L (exercise) + 0.5L (heat) = 4.3L
70kg pregnant woman, moderate activity: 70 × 0.035 = 2.45L + 0.3L = 2.75L
Is 2 Litres Enough?
"Drink 2 litres a day" is Canada's most common generic hydration advice. Here's when it's accurate and when it falls short:
2L is adequate for:
- Women under 60kg with sedentary to light activity
- Cool weather, minimal sweating
- Low to moderate protein diet
2L is NOT enough for:
- Men (average Canadian male weighs ~84kg → needs 2.9L baseline)
- Active adults on training days
- Summer heat
- Sauna users
- High protein diets
The Mammoth Mug 2.5L covers the gap — 2.5L in one fill is adequate for most average adults and leaves margin for active and warm days.
🛒 One Fill. Full Target.
Calculate your target above. For most adults it's 2–3L from drinks. The Mammoth Mug 2.5L — one fill covers it. Time markings to pace through the day. BPA-free Tritan. Canadian brand at Sport Chek.
The Urine Colour Confirmation
Your calculated target is a starting point. Urine colour confirms whether you're hitting it:
| Colour | Meaning |
|---|---|
| Clear | Possibly over-hydrating |
| Pale yellow ✅ | On target |
| Yellow | Slightly under — drink 250mL |
| Dark yellow | Dehydrated — drink 500mL now |
| Amber/orange | Significantly dehydrated |
Check in the afternoon — morning urine is normally darker from overnight concentration.
Canadian Context: Why Litres Matter Here
Canada uses metric — litres are the natural unit for hydration guidance. The American "8 × 8oz glasses" translates to approximately 1.9L — below the needs of most Canadian adults. Using litres with a body weight formula is more accurate and more culturally aligned for Canadian users.
The water intake calculator gives your exact personal target in both litres and mL.
🛒 Your Litres. Your Bottle.
The Mammoth Mug 2.5L — 2.5 litres, time markings, Tritan (BPA-free, DEHP-free, EA/AA-free). Fill once. Finish it. Canadian brand since 2014. At Sport Chek.
Related: how much water you need based on weight
Related: how much water to drink to flush kidneys
Frequently Asked Questions
How many litres of water should I drink a day in Canada?
2–3L from drinks is appropriate for most Canadian adults. Use the formula: body weight (kg) × 0.035 = daily baseline in litres. Add 0.5L per 30 min of exercise.
Is 2 litres of water a day enough?
For sedentary women under 60kg: approximately. For most men and active adults: no — they need 2.5–4L depending on weight and activity.
Is 3 litres of water a day too much?
Not for most active adults. A 85kg man training 60 minutes needs ~4L on training days. 3L is appropriate for a 80–85kg person with light activity.
How many glasses is 2 litres?
2L ÷ 0.25L (standard 250mL glass) = 8 glasses. This is where the "8 glasses a day" recommendation comes from — it approximates 2L for a small, sedentary adult.
Does coffee count toward my daily litres?
Yes — at 1–3 cups, coffee is net hydrating despite its mild diuretic effect. Count it toward your total but don't rely on it as your primary fluid source.
How much water should a 70kg person drink in litres?
Baseline: 70 × 0.035 = 2.45L per day. Add 0.5–1L on training days.
What is the easiest way to drink 2.5 litres a day?
Fill a Mammoth Mug 2.5L at the start of the day. Put it on your desk. Follow the time markings. Finish it by evening. Zero tracking, zero counting.
Do I need to drink more litres in summer?
Yes — add 0.5L in hot weather (25°C+) and 0.75–1L in very hot or humid conditions above your baseline.
