Are these light bulbs interchangeable?
 

I'm looking to replace some of my lights with LEDs, so I've been doing some research and came across these questions:

1. Can 194 bulbs fit into 7440 sockets (and vice versa)?
2. Similarly, can 3157 bulbs fit into 7443 sockets (and vice versa)?

Those bulbs look very similar and I can't tell if they're interchangeable or not.

Thanks in advance!

So after googling for an entire afternoon, I found some relevant information. 194 bulbs are too small to fit into 7440 sockets. They're entirely different sizes. 3157 and 7443 are much closer in size, only off by a fraction of a millimeter.

Here are the links to the size comparisons:
3157: 25-LED 3156/3157 LED Bulb Specifications
7443: 15-LED 7443/7440 Bulb Specifications
194: WLED-xLX Specifications

Anyway, the reason why I was concerned was because I mistakenly bought 3157 brake lights even though the Fit uses 7443. When my lights arrive, I will try them and post my results.

Single and dual fillament. That's probably gonna be different as well as bases.

I guess what I don't understand is why you just don't call a reputable online LED seller if none is available where you live.

By calling they will tell you exactly what you need without relying on the internet and take the chance of making a mistake. Take it from me the net is full of garbage info.

Do not waste your money on those 7443 you mention. They are crap. I just tried them. The light is all pointed straight back so does not fill reflector. I had a tail burnt out so replaced yesterday with GE Nighthawks which claim to be 20% brighter and yes they are.

If you are going to try LEDs then get the festoon type that shine to sides as well.

I didn't get the LEDs in the link. I only use the pics as a reference for the dimensions to see if the bulbs would fit.

Anyway, thanks for everyone's help!