Bottle Size Guide: How to Choose the Right Capacity
Picking a bottle size comes down to time away from water, how you carry it, and how often you like to refill. Use the quick picks, the oz ⇄ mL calculator, and the conversion table below.
TL;DR — Quick Picks
- Commuting & desk: mid-size (around 22 oz / ~650 mL) — easy to carry, fits most cup holders.
- Gym & day trips: larger (e.g., 40 oz / ~1.18 L) — fewer refills for long sessions.
- Kids / short outings: 12–18 oz / 355–532 mL — lighter and simpler to manage.
- All-day outdoors: 32–64 oz (0.95–1.9 L) — fewer stops, but heavier in the bag.
How to choose your size
- Time away from water: More hours out → larger bottle (or plan refills).
- Carry method: Backpack/tote can handle bigger sizes; hand-carry prefers mid-size.
- Cup holder fit: Cars/prams usually prefer the mid-diameter range.
- Refill preference: Hate refilling? Go larger. Love ice-cold sips? Smaller bottle + more refills.
- Lid type: Straw lids encourage sipping; chug lids are faster. See Accessories & Lids.
Oz ⇄ mL conversion table
1 US fl oz = 29.5735 mL. Use this quick table:
| Size (oz) | Millilitres (exact) | Litres | Typical uses |
|---|---|---|---|
| 12 | 354.9 mL | 0.355 L | Kids, short walks, coffee/tea |
| 16 | 473.2 mL | 0.473 L | Commute, quick workouts |
| 18 | 532.3 mL | 0.532 L | School, light hiking |
| 22 | 650.6 mL | 0.651 L | Cup-holder friendly daily carry (22 oz range) |
| 24 | 709.8 mL | 0.710 L | Longer classes/meetings |
| 32 | 946.4 mL | 0.946 L | Half-day sessions, gym |
| 40 | 1182.9 mL | 1.183 L | All-day hydration, fewer refills (40 oz range) |
| 64 | 1892.7 mL | 1.893 L | Camping, team sports bench |
How many refills do I need?
If your daily target is 2 L or 3 L:
- 22 oz (~0.651 L): ~3 refills for 2 L (≈1.95 L), ~5 refills for 3 L.
- 40 oz (~1.183 L): ~2 refills for 2 L (≈2.37 L), ~3 refills for 3 L.
Use-case guide
- Commute & office: 22–24 oz — see the 22 oz collection.
- Gym & training: 32–40 oz — see the 40 oz collection.
- Care & extras: Swap lids, add straws, clean properly — browse Accessories and check our FAQ & Shipping & Returns.
- Teams & events: Need one size for a group? Ask about Bulk & Custom Orders.
Quick decision flow: Out < 3 hrs → 16–22 oz. 3–6 hrs → 22–32 oz. All day → 32–40 oz. Hand-carry → 22–24 oz. Backpack/tote → 32–40 oz.
Note: values rounded for everyday use. For precise work, use the calculator above.