How to make sure your next water bottle fits your car cup holder

It works in the sense that the water bottle no longer falls over at the first corner. But look at what has happened. The cup holder adapter has taken away the space inside the car cup holder. The water bottle often sits high inside the cabin and may still have slack around it.

I have driven with a water bottle perched in one of these adapters, tall enough to block controls and moving around on every corner. A car cup holder adapter may be a fair solution for a water bottle you already own and love. In my opinion these adapters are not the best solution for a good driving or drinking experience on the road.

The technique below uses common kitchen items and I have found it simple and effective.

Tools needed:

• Small stainless steel kitchen tongs

• Sheet of paper

• 12in/30cm ruler

• Fabric tape measure

• Optional – extra set of hands

Method:

1. Measure the narrowest part of your cup holder (narrowest internal diameter). Most car cup holders taper, so the narrowest point is usually at the base.

1. Let the tongs open inside the holder until both tips touch opposite walls at the narrowest point

1. Hold the tong arms at exactly that spread while you lift them out

1. Then measure the gap between the tips of the tongs with a ruler

1. Measure the widest part of your cup holder (widest internal diameter). The widest diameter is generally near the top rim.

1. Let the tongs open inside the holder until both tips touch opposite walls at the widest point

1. Hold the tong arms at exactly that spread while you lift them out

1. Then measure the gap between the tips of the tongs with a ruler

1. Measure the depth of your cup holder.

1. Stand the ruler on the floor of your holder and read the depth from the base to the rim.

1. Measure the clear space directly above your cup holder. Note: Nothing above the holder? Skip this step, height won’t be an issue.

1. Run the fabric tape measure from the floor of the holder vertically straight up to the underside of the closest obstruction above it. It could be a dash overhang, an armrest, a protruding console. Fabric bends in under an overhang where a rigid tape won’t.

1. Draw the complete cup holder profile on a sheet of paper.

1. Draw a line as long as the base measurement 1 at the bottom of the paper

1. Draw a point directly above the center of this line that is as high as the depth measurement 3

1. Draw the rim line through point (b): parallel to the base line (a), as long as the widest measurement 2 and centered on the point (b)

1. Draw straight lines connecting the ends of the Base line and Rim line

Four checks that tell you whether a water bottle fits your car cup holder

Any bottle or tumbler worth considering publishes its diameter and height (we list exact dimensions for every vessel we make). Run the following four checks in order to see whether a bottle will fit your cup holder.

1. Check 1 – Does it fit at all? A bottle's widest point must be narrower than the cup holder's widest internal diameter (2) unless it is tapered, and the bottle must be shorter than the space above the cup holder. This is the clear space measurement (4) minus the depth measurement (3). A water bottle taller or wider than this (unless it is tapered) can’t fit into the holder at all.

1. Check 2 – Does it sit deep enough? Mark the bottle's diameter on your drawing and see where it meets the tapered walls: that is where it will wedge in and stop. I recommend a bottle that slides in at least 2in/5cm below the rim. Any shallower and a firm brake may send it into the footwell.

1. Check 3 – Will it rattle? A bottle narrower than the base diameter will sit all the way down, which is the most stable, but it shouldn’t be more than about 1/4in or 6mm narrower. Any more than that and it will move around significantly while driving which can be distracting.

1. Check 4 – Is the bottle tapered? Plenty of tumblers narrow toward the base, which makes a single diameter number useless for the depth check. So build the bottle's profile too using another sheet of paper:

1. Find a true side-on photo of the bottle and confirm its widest diameter from the specifications

1. On a large screen, zoom the photo until the widest point measures the same as the specifications using a ruler held up to the screen

1. Hold the sheet of paper over the screen and carefully trace the outline with a feather-light touch and blunt pencil. Note: screens can be damaged by point pressure so be careful.

1. Cut the tracing out, stand it in your cup holder cross section drawing and slide it down until the sides touch. You can now see exactly how deep it will sit and how tall it will stand in the cabin.

Measure and cut the gamble

There is no car cup holder standard, and adapters often add other problems. A little time spent measuring and drawing your cup holder's true profile means every water bottle on your shortlist can be checked based on its specifications. Know what will and won’t fit your car cup holder properly without the gamble.