{"id":26384,"date":"2025-12-10T10:58:02","date_gmt":"2025-12-10T10:58:02","guid":{"rendered":"https:\/\/www.sage.com\/en-gb\/blog\/?post_type=sage_glossary&#038;p=26384"},"modified":"2025-12-10T10:58:03","modified_gmt":"2025-12-10T10:58:03","slug":"what-is-self-assessment","status":"publish","type":"sage_glossary","link":"https:\/\/www.sage.com\/en-gb\/blog\/glossary\/what-is-self-assessment\/","title":{"rendered":"What is Self Assessment?"},"content":{"rendered":"<header class=\"entry-header has-dark-background-color entry-header--has-illustration entry-header--has-illustration--generic\">\n\t<div class=\"container\">\n\t\t<div class=\"entry-header__row row align-center\">\n\t\t\t<div class=\"col col-lg-7 col-xlg-6 entry-header__content\">\n\t\t\t\t\t\t\t<div class=\"component component-single-header\">\n\t\t\t\t\t\t\t\t\t\t<div class=\"entry-header__misc text--subtitle text--uppercase text--small\">\n\t\t\t\t\t\t\t<a href=\"https:\/\/www.sage.com\/en-gb\/blog\/glossary\/\" class=\"entry-header__link\">Glossary definition<\/a>\t\t\t\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t<div class=\"entry-title-wrapper\">\n\t\t\t\t\t<h1 class=\"entry-title\">\n\t\t\t\t\t\tWhat is Self Assessment?\t\t\t\t\t<\/h1>\n\t\t\t\t<\/div>\n\n\t\t\t\t\n\t\t\t\t\n\t\t\t\t\n\t\t\t<\/div>\n\n\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t<\/div>\n\t<div class=\"single-post-details container\">\n\t\t<div class=\"col\">\n\t\t\t<span class=\"reading-time\"> min read<\/span>\n\t\t<button\n\t\t\ttype=\"button\"\n\t\t\tclass=\"social-share-button button button--icon button--secondary js-social-share-button\"\n\t\t\tdata-share-title=\"What is Self Assessment?\"\n\t\t\tdata-share-url=\"https:\/\/www.sage.com\/en-gb\/blog\/glossary\/what-is-self-assessment\/\"\n\t\t\tdata-share-text=\"Please read this interesting article\"\n\t\t>\n\t\t\t<span class=\"social-share-button__share-label\">Share<\/span>\n\t\t\t<span class=\"social-share-button__copy-label\" hidden>Copy Link<\/span>\n\t\t\t<span class=\"social-share-button__copy-tooltip\" aria-hidden=\"true\" hidden>Copied<\/span>\n\t\t<\/button>\n\n\t\t\t\t<\/div>\n\t<\/div>\n<\/header>\n\n\n\n\n\n<p>Self Assessment is the name of the system used by HMRC to collect Income Tax.<\/p>\n\n\n\n<p>It\u2019s mostly used by people who are self-employed, or landlords with rental income. But it can also be used by partners in a business partnership, if you have to pay Capital Gains Tax, if you have to pay the High Income Child Benefit Charge, or if you\u2019ve simply got any untaxed income, such as income from savings, investments or pensions.<\/p>\n\n\n\n<p>To use Self Assessment, you\u2019ll first need to register with HMRC. This gives you a Unique Taxpayer Reference, or UTR, that will be linked to your account. Each year you can then either send a paper tax return by 31 October following the end of the tax year, or submit an online tax return by 31 January. The majority of people use the online service.<\/p>\n\n\n\n<p>The tax return details your business income and expenses, by which your tax liability is derived. If you use the online Self Assessment tax return, HMRC will calculate this for you.<\/p>\n\n\n\n<p>Any outstanding tax liability must be paid by 31 January, as well as any payment on account for the current year, if HMRC has agreed this with you.<\/p>\n\n\n\n<p>If you\u2019re employed then Income Tax is collected automatically by your employer from your wages via the Pay as you Earn (PAYE) system, so there\u2019s usually no need to use Self Assessment unless you have additional income outside of this (e.g. you\u2019re a landlord, or you have a side hustle that generates more than the \u00a31,000 trading allowance).<\/p>\n\n\n\n<div class=\"single-cta gated-content\">\n\t<div class=\"single-cta__positioner\">\n\t\t<div class=\"single-cta__wrapper has-dark-background-color\">\n\t\t\t<div class=\"single-cta__content\">\n\t\t\t\t\t\t\t\t<h2 class=\"single-cta__title h3\">E-Book: Get Self Assessment right<\/h2>\n\n\t\t\t\t\t\t\t\t\t<div class=\"single-cta__description\">\n\t\t\t\t\t\t<p><!-- wp:paragraph --><\/p>\n<p class=\"\">Download your free copy of this essential guide and get the support you need with your Self Assessment tax returns.<\/p>\n<p><!-- \/wp:paragraph --><\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a\n\t\t\t\t\t\thref=\"#gate-b070c479-ac3c-48cf-b77a-f696b6d06d6b\"\n\t\t\t\t\t\tclass=\"single-cta__button button button--primary\"\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t>Download your free guide<\/a>\n\t\t\t\t\t\t\t<\/div>\n\n\t\t\t\t\t\t\t<div class=\"single-cta__downloads\">\n\t\t\t\t\t\n\t\t\t\t\t1,200 readers have downloaded this guide\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<img decoding=\"async\" width=\"1440\" height=\"810\" src=\"https:\/\/www.sage.com\/en-gb\/blog\/wp-content\/uploads\/sites\/10\/2022\/04\/GettyImages-1146164056-1440x810.jpg\" class=\"single-cta__image\" alt=\"Woman applying for business credit line\" loading=\"lazy\" srcset=\"https:\/\/www.sage.com\/en-gb\/blog\/wp-content\/uploads\/sites\/10\/2022\/04\/GettyImages-1146164056-1440x810.jpg 1440w\" sizes=\"auto, (min-width: 48em) 33vw, 100vw\" \/>\t\t\t<\/div>\n<\/div>\n\n\n\n<p><\/p>\n\n\n<div class=\"single-cta\">\n\t<div class=\"single-cta__positioner\">\n\t\t<div class=\"single-cta__wrapper has-dark-background-color\">\n\t\t\t<div class=\"single-cta__content\">\n\t\t\t\t\t\t\t\t<h2 class=\"single-cta__title h3\">Subscribe to the Sage Advice newsletter<\/h2>\n\n\t\t\t\t\t\t\t\t\t<div class=\"single-cta__description\">\n\t\t\t\t\t\t<p>Join more than 500,000 UK readers and get the best business admin strategies and tactics, as well as actionable advice to help your company thrive, in your inbox every month.<\/p>\n\t\t\t\t\t<\/div>\n\t\t\t\t\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t<a\n\t\t\t\t\t\thref=\"#gate-b1a63862-3fa0-4a5e-bb67-c76b88bbc6b8\"\n\t\t\t\t\t\tclass=\"single-cta__button button button--primary\"\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t>Subscribe now<\/a>\n\t\t\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<\/div>\n\n\t\t\t\t\t<img decoding=\"async\" width=\"1440\" height=\"810\" src=\"https:\/\/www.sage.com\/en-gb\/blog\/wp-content\/uploads\/sites\/10\/2022\/04\/GettyImages-1073797282-1-1440x810.jpg\" class=\"single-cta__image\" alt=\"\" loading=\"lazy\" srcset=\"https:\/\/www.sage.com\/en-gb\/blog\/wp-content\/uploads\/sites\/10\/2022\/04\/GettyImages-1073797282-1-1440x810.jpg 1440w\" sizes=\"auto, (min-width: 48em) 33vw, 100vw\" \/>\t\t\t<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Self Assessment is the name of the system used by HMRC to collect Income Tax. It\u2019s mostly used by people who are self-employed, or landlords with rental income. But it can also be used by partners in a business partnership, if you have to pay Capital Gains Tax, if you have to pay the High [&hellip;]<\/p>\n","protected":false},"author":280,"featured_media":0,"template":"","meta":{"_sage_video":false,"footnotes":""},"tags":[27],"class_list":["post-26384","sage_glossary","type-sage_glossary","status-publish","hentry","tag-tax"],"distributor_meta":false,"distributor_terms":false,"distributor_media":false,"distributor_original_site_name":"Sage Advice UK","distributor_original_site_url":"https:\/\/www.sage.com\/en-gb\/blog","push-errors":false,"_links":{"self":[{"href":"https:\/\/www.sage.com\/en-gb\/blog\/api\/wp\/v2\/sage_glossary\/26384","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.sage.com\/en-gb\/blog\/api\/wp\/v2\/sage_glossary"}],"about":[{"href":"https:\/\/www.sage.com\/en-gb\/blog\/api\/wp\/v2\/types\/sage_glossary"}],"author":[{"embeddable":true,"href":"https:\/\/www.sage.com\/en-gb\/blog\/api\/wp\/v2\/users\/280"}],"version-history":[{"count":0,"href":"https:\/\/www.sage.com\/en-gb\/blog\/api\/wp\/v2\/sage_glossary\/26384\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.sage.com\/en-gb\/blog\/api\/wp\/v2\/media?parent=26384"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.sage.com\/en-gb\/blog\/api\/wp\/v2\/tags?post=26384"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}