* Avg daily steel output dipped 5 pct from Nov to 2.46 mln T
* But overall 2018 production hit record -stats bureau
* Profit-margins shrank towards year-end on oversupply (Adds graphic)
BEIJING, Jan 21 (Reuters) - China's average daily steel output in December hit its lowest level since March, according to Reuters calculations based on official data, as producers cut output amid shrinking profit-margins.
Total output fell to 76.12 million tonnes last month from 77.62 million tonnes in November, but was up 8.2 percent from December 2017, data from the National Bureau of Statistics showed on Monday.
That means average daily steel output dipped 5 percent from the month before to 2.46 million tonnes, the lowest level since the 2.39 million tonnes recorded in March, according to Reuters calculations.
The world's biggest steel maker churned out a record 928.26 million tonnes of crude steel in 2018, the data showed, up 6.6 percent from 2017, buoyed by firm demand in the first three quarters of the year.
However, profits at steel mills have plunged nearly 60 percent since November on stronger-than-expected supply after Beijing ditched blanket measures to cut industrial production over the winter.
The environment ministry has vowed to adopt more efficient and targeted measures to fight pollution in 2019.
An executive at China's Iron and Steel Association said last week that the country's steel industry would shift its focus to optimising capacity structure in 2019 from reducing overall capacity.
China currently has around 980 million tonnes of steelmaking capacity.
A government consultancy predicted last month that steel output would slip back to 900 million tonnes in 2019, curbed by cooling demand in major downstream sectors such as property, automobiles and energy.
(Reporting by Muyu Xu and Dominique Patton; Editing by Joseph Radford)