Remember the good old-fashioned classroom maps?
Coverage is approximately 15-20m2 per litre per coat (160-220 sq.ft. per 33.8 fl.oz. per coat). This equates to about £6.53 per square metre (US $0.79 * per sq.ft.) for the finished job done in three coats (one coat diluted and two further coats undiluted).
The finished job for Farrow and Ball Exterior Eggshell (plus primer) is approximately £8.92 per m2 and Dulux Weathershield Quick Dry Exterior Satin (plus primer and undercoat) £11.13 per m2.
(* Exchange rate $1.30 to £1.00, December 2020.)