About D'Hondt Calculators

The exact genealogy I have forgotten, but D'Hondt election calculation dates back to my earliest days doing programming — at some point I wrote a (now long-lost) MS-DOS version, and around 1998 I ported the code to Windows, which later underwent a lot of one-off maintenance. Around the mid-late 2000s I made various web-based variants, which in 2010 I migrated from my personal website to this dedicated domain. Today this website is maintained as a resource for anyone wanting to calculate D'Hondt election results, and includes preset results from previous elections.


Party votes
This is the number of votes for a given party, and can be a raw vote count or a percentage, as long as all entered values are proportional to each other.
FPTP seats
This is only relevant to additional-member systems where the allocation of seats takes account of party wins within separate constituency seats. The algorithm used is that employed by elections to the Scottish parliament, where the number of constituency seats won by a party is added to the denominator for the party.
In election results lists, the margin shown after the last seat results is how short a party is from gaining the last seat. This is clearly zero for the party that actually gained the seat, but I know a lot of interest is often who has/had the best chance of snatching last place.
Party seats
The number of seats won in the election calculation. Note that this excludes any FPTP (i.e. constituency) seats the party make have.

Available calculators

Three flavours of D'Hondt calculators are provided on this site — two are on-line and one is off-line — and these are explained below. The reasons for having so many is historical, and they were all written at different times, so use whichever one you feel is best:-
Server-side CGI/PHP
Traditional server-side based calculator. Each recalculation will involve a round-trip to the webserver, which may be very slow dependent on your location and internet connection speed, but this calculator is the most compatible. It does not use any client-side scripting, and has been tested with Links.
Client-side Javascript
Client-side Javascript-based calculator. This is the preferred calculator, especially if you intend to play around with numbers, but at least in the past this variant has had compatibility problems with some web browsers.
Off-line calculators
These are Windows-based calculators I wrote in the past which can be downloaded for off-line use. It is possible to run them on non-Microsoft platforms, but these versions are included here for historical reasons as much as practical use.

GDPR privacy statement

This website does not use cookies, and does not make use of any cross-site techniques. Data sent back to the webserver by the PHP-based calculator is discarded once calculation of the seat result from said data has been completed.

Contact details

I can be emailed at remy.horton (at) gmail.com