The best way to determine what size faucet you need is to measure the distance between the holes. Alternatively, you can also measure your existing faucet and purchase one with the same measurements.
You must examine the handles and faucet now installed in the bathtub to locate a replacement faucet set that will be compatible with the plumbing.
In most cases, this will also involve measuring the pipe onto which the spout fits to obtain a faucet spout that is appropriate and not excessively long or short.
Instead of purchasing the faucet’s handles, stems, and replacement spout separately, it is better to go for a bathtub faucet kit that includes all of these components. This will help ensure that your fittings’ appearance is consistent.