There's no standard as far as I am aware and I've fitted and replaced quite a few sinks over the years. If you can find an exact fit which might take a bit of luck, great, but it's usually possible to find one just a few millimetres larger one way or another and fit that which does of course require a bit of cutting.
Even if there was a true standard size, like so many measurements in construction and materials, it will often be a "Nominal size" rather than exact.
The size of the cutout is what's important here. Measure from underneath if possible or measure from above but remember to take the lip/flange into account and see if you can find one of the appropriate dimensions. There are so many out there you will find one to fit with little or no cutting if lucky. Nothing beats having an exact measurement of the hole in your worktop and going out to a merchant or two armed with a tape measure to see if you can find a good fit.
Unfortunately there's no exact, straight answer to this one.