English Chess Forum

Hi all,

I was wondering if anyone could tell me, definitely, what is the formula for converting an ECF grade to a FIDE rating? I have been told, by various different people, that (ECF x 8 ) + 650 = FIDE and that (ECF x 8 ) + 600 = FIDE. Obviously both of these can't be right.

However, I then look at the British Championship 2010 events list http://www.britishchess2010.com/main_events.htm where the grading-restricted entry sections have alternative 4-figure grades attached = e.g. Under 140/1600 Championship, Under 125/1450 Weekender. My maths was never that good, but I'm pretty sure that neither of the above formulae convert 140 into 1600 and 125 into 1450. Are these 4-figure grades not in fact FIDE equivalents? Or is the BCC using a conversion formula unknown to me for its rating conversions?

Many thanks,

Alexander.

The 8 which appears in the formula is demanded by theory, the constant (650/600) could be anything (almost) and can only be determined by examining the data which doesn't exist at the rating levels you are discussing.

The ECF to FIDE is normally given as x8 + 650.

For these events we are normally talking about conversion from the other home nations. In Scotland performance of players who took part in events north and south of the border was examined and a conversion formula of x10 + 180 was found to be a satisfactory solution to the problem. This formula has been successfully used in a number of congresses including Blackpool and Scarborough. It is obviously used in all events in Scotland and by the CS grading system.

Allowing for rounding this is the formula that has been used. In many cases it has meant that the 4 figure numbers given have not changed from previous years or have changed little. This is thought to be reasonable as neither the Welsh nor Scottish systems have reported the faults identified in the English one.

I am of course biased in thinking this conversion more accurate since I was one of those involved in coming up with it, but Geoff Jones also did a number of comparisons before opting to use it at Blackpool.

I hope this answers your question.

Alexander Hardwick wrote:I was wondering if anyone could tell me, definitely, what is the formula for converting an ECF grade to a FIDE rating? I have been told, by various different people, that (ECF x 8 ) + 650 = FIDE and that (ECF x 8 ) + 600 = FIDE. Obviously both of these can't be right.

See http://grading.bcfservices.org.uk/help.php#elo for the official conversion tables for grading purposes. One of the formulae you quote is used for conversion of FIDE Elo ratings to ECF and the other for the conversion of national Elo ratings.

Ian Thompson wrote:

Alexander Hardwick wrote:I was wondering if anyone could tell me, definitely, what is the formula for converting an ECF grade to a FIDE rating? I have been told, by various different people, that (ECF x 8 ) + 650 = FIDE and that (ECF x 8 ) + 600 = FIDE. Obviously both of these can't be right.

See http://grading.bcfservices.org.uk/help.php#elo for the official conversion tables for grading purposes. One of the formulae you quote is used for conversion of FIDE Elo ratings to ECF and the other for the conversion of national Elo ratings.

Thanks!!!