Cyfuniad o lythrennau a rhifau a ddefnyddir mewn sawl gwlad i ddynodi cyfeiriad post, gan amlaf trwy ei roi ar ddiwedd cyfeiriad unigol ar amlen, yw côd post (côd zip yn yr Unol Daleithiau). Mae ei fanyldeb yn amrywio. Mewn rhai gwledydd, fel Tiwnisia er enghraifft, dim ond dinas, tref neu bentref a ddynodir gan gôd post, ond mewn gwledydd eraill, fel Cymru er enghraifft, mae'r côd yn fwy manwl ac yn dynodi stryd neu ardal.

Map o wledydd Prydain gan ddangos ardaloedd codau post a'u ffiniau daearyddol ynghyd a dolennau i ardaloedd rhanbarthol.AB postcode areaAL postcode areaB postcode areaBA postcode areaBB postcode areaBD postcode areaBH postcode areaBL postcode areaBN postcode areaBR postcode areaBS postcode areaBT postcode areaBT postcode areaCA postcode areaCB postcode areaCF postcode areaCH postcode areaCM postcode areaCO postcode areaCR postcode areaCT postcode areaCV postcode areaCW postcode areaDA postcode areaDD postcode areaDE postcode areaDG postcode areaDH postcode areaDL postcode areaDN postcode areaDT postcode areaDY postcode areaE postcode areaEC postcode areaEH postcode areaEN postcode areaEX postcode areaEX postcode areaFK postcode areaFY postcode areaG postcode areaGL postcode areaGU postcode areaGY postcode areaHA postcode areaHD postcode areaHG postcode areaHP postcode areaHR postcode areaHS postcode areaHU postcode areaHX postcode areaIG postcode areaIM postcode areaIP postcode areaIV postcode areaJE postcode areaKA postcode areaKA postcode areaKT postcode areaKW postcode areaKW postcode areaKY postcode areaL postcode areaLA postcode areaLD postcode areaLE postcode areaLL postcode areaLN postcode areaLS postcode areaLU postcode areaM postcode areaME postcode areaMK postcode areaML postcode areaN postcode areaNE postcode areaNG postcode areaNN postcode areaNP postcode areaNR postcode areaNW postcode areaOL postcode areaOX postcode areaPA postcode areaPA postcode areaPA postcode areaPE postcode areaPH postcode areaPH postcode areaPH postcode areaPH postcode areaPL postcode areaPO postcode areaPR postcode areaRG postcode areaRH postcode areaRM postcode areaS postcode areaSA postcode areaSE postcode areaSG postcode areaSK postcode areaSL postcode areaSM postcode areaSN postcode areaSO postcode areaSP postcode areaSR postcode areaSS postcode areaST postcode areaSW postcode areaSY postcode areaTA postcode areaTD postcode areaTF postcode areaTN postcode areaTQ postcode areaTR postcode areaTR postcode areaTS postcode areaTW postcode areaUB postcode areaW postcode areaWA postcode areaWC postcode areaWD postcode areaWF postcode areaWN postcode areaWR postcode areaWS postcode areaWV postcode areaYO postcode areaZE postcode areaZE postcode areaZE postcode areaZE postcode areaAL postcode areaBR postcode areaCM postcode areaCR postcode areaDA postcode areaE postcode areaEC postcode areaEN postcode areaGU postcode areaHA postcode areaIG postcode areaKT postcode areaN postcode areaNW postcode areaRM postcode areaSE postcode areaSL postcode areaSM postcode areaSW postcode areaTN postcode areaTW postcode areaUB postcode areaW postcode areaWC postcode areaWD postcode areaWD postcode areaBB postcode areaBD postcode areaBL postcode areaCH postcode areaCW postcode areaDE postcode areaDN postcode areaFY postcode areaHD postcode areaHG postcode areaHX postcode areaL postcode areaLA postcode areaLL postcode areaLL postcode areaLS postcode areaM postcode areaNG postcode areaOL postcode areaPR postcode areaS postcode areaSK postcode areaST postcode areaWA postcode areaWF postcode areaWN postcode areaYO postcode area
Map o wledydd Prydain gan ddangos ardaloedd codau post a'u ffiniau daearyddol.

Codau post yn y DU

golygu

Yng Nghymru a gwledydd eraill y DU, mae codau post yn cynnwys tair elfen. Yn y gyntaf ceir llythyren neu ddwy i ddynodi'r canolfan sortio ar gyfer yr ardal, yn ail ceir rhif sy'n dynodi'r ddinas, tref neu bentref, ac yn drydydd, ar ôl bwlch, ceir cyfuniad o rif(au) a llythrennau sy'n dynodi ardal drefol neu stryd a.y.y.b. SY23 3HH, er enghraifft, yw côd post Llyfrgell Genedlaethol Cymru, gyda'r SY yn sefyll am Amwythig (Shrewsbury=SY) a 23 yn dynodi Aberystwyth.

Gweler hefyd

golygu