Informal learning is characterized "by a low degree of planning and organizing in terms of the learning context, learning support, learning time, and learning objectives". It differs from formal learning, non-formal learning, and self-regulated learning, because it has no set objective in terms of learning outcomes, but an intent to act from the learner's standpoint. Typical mechanisms of informal learning include trial and error or learning-by-doing, modeling, feedback, and reflection. For learners this includes heuristic language building, socialization, enculturation, and play. Informal learning is a pervasive ongoing phenomenon of learning via participation or learning via knowledge creation, in contrast with the traditional view of teacher-centered learning via knowledge acquisition. Estimates suggest that about 70-90 percent of adult learning takes place informally and outside educational institutions.

Non-formal learning includes various structured learning situations which do not either have the level of curriculum, syllabus, accreditation and certification associated with 'formal learning', but have more structure than that associated with 'informal learning', which typically take place naturally and spontaneously as part of other activities. These form the three styles of learning recognised and supported by the OECD.