A bestseller every season, the Iron Flask 40 oz water bottle has many practical features and everyday benefits. Our 40 oz bottle is built to last, featuring indestructible stainless steel and durable BPA-free lids. This extra large bottle is the ideal size for extra large hydration and comes with three lids for great value at an affordable price.

Not only is the 40 oz water bottle a sustainable option, but it also gives you an easy way to track your daily water intake. How big is a 40 oz bottle? Check out a few size comparisons for easy reference:

  • How many bottles of water is 40 oz? The 40 oz stainless steel water bottle is equivalent to approximately two “regular” sized plastic bottles of water, at 16.9 fl oz each.
  • How many 40 oz water bottles make a gallon? That’s 0.31 gallons, or about 1/3. You can drink three full 40 oz insulated stainless steel water bottles to get a gallon of hydration.

40 oz Iron Flask Water Bottle

Shop 40 oz Insulated Water Bottles at Iron Flask

There's a reason why the 40 oz bottle at Iron Flask is so popular. We've designed it with lightweight stainless steel, making it easy to carry. Because of its substantial size, the 40 fl oz water bottle also provides maximum hydration with minimum refills throughout the day.

Another benefit of the 40 oz insulated water bottle is the double-walled vacuum insulation, which maintains hot or cold temperatures for hours. Our 40 oz reusable water bottle also comes with three extra lids, adding more value and convenience to the already affordable price. Shop for your own 40 oz wide mouth vacuum insulated stainless steel water bottle, including accessories like the 40 oz water bottle sleeve, and use the top-rated 40 oz reusable water bottle to stay healthy while reducing plastic waste. Include the 40 oz double insulated water bottle on your checklist and have everything you need to stay hydrated on all your adventures.