If you are asking about conventional bales, the width and height are standard across almost all conventional balers.
36cm (1 and a bit feet)high by 46cm (just over 1.5 feet) wide. The length can be adjusted to anything from 0.3 - 1.3m long. It is usually better to go by weight with hay bales weighing about 12 - 15 kg and straw about 10kg.