Wiktionary Appendix:Irregular verbs

The past participle and the simple past are usually the same if the simple past ends in -ed. If the simple past does NOT end in -ed, the past participle is probably different from the simple past.

Forms marked Brit are used in Britain but rarely found in the US. Forms marked US are used in the US but are rare or considered incorrect in Britain. Forms with neither label may be considered standard in both main varieties of English.