It debuted at number three on the UK Albums Chart and the US Billboard 200, earning Goulding her highest-charting record in the latter country and her highest first-week sales figures in both territories.

The song received positive reviews and performed well commercially, reaching the top 10 in Australia, Canada, New Zealand and the United Kingdom, and number 13 on the Billboard Hot 100.

[13] The album includes Goulding's song "Love Me like You Do", which was originally released as a single from the soundtrack to the 2015 film Fifty Shades of Grey and became a commercial success worldwide.

[14] Peter Robinson of Q remarked that the album "seems to enjoy pushing pop's boundaries, and six years into her career feels like Goulding's first true superstar moment", while noting that her "nuanced lyrics steer Delirium away from homogeneity".

"[19] Matt Collar of AllMusic opined that "it's the unexpectedly appealing combination of Goulding's distinctive voice and the melismatic R&B bent of the songs on Delirium that makes for such an ecstatic listen.

"[5] Entertainment Weekly's Kyle Anderson viewed Delirium as "too well-constructed and honestly ambitious, and the tracks that land in Goulding's comfort zone [...] rank among her best work.

Throughout Delirium, her vocals are often double-tracked in an attempt to circumvent this, but it largely fails, and the singing is forever fighting for attention amid a swamp of crashing beats and over-zealous synths.