What’s the difference between intrinsic and relative valuation?

Intrinsic valuation is based on future cash flows, while relative valuation is based on the multiples that comparable companies are trading at or the multiples that previous acquisitions (precedent transactions) have occurred.

Intrinsic valuation is driven more by assumptions while relative valuation is driven by the market.
Intrinsic valuation is can be done on companies with no comparable companies while relative valuation requires similar comparable companies or past acquisitions.

Intrinsic valuation methods like DCF models require detailed forecasts for a longer projection period while relative valuation typically only requires trailing (last twelve months) and/or forward (next twelve months) metrics.