Knowledge Base - TaxCalc

	MTD IT for agents - authorising TaxCalc to connect to HMRC In order to use TaxCalc to submit and retrieve information for MTD income tax for your clients, HMRC require authorisation between the software and...
	18 Jun, 2026 Views: 42

	Basis Period Transition when more than one accounting period (2023/24) How should I enter details of multiple accounting periods for a self employment? From tax year 2024-25 onwards, self-employed individuals will be...
	17 Jun, 2026 Views: 7908

	Basis Period in the transitional year 2023/24 - how to use the basis period calculator Basis Period Entries in TaxCalc (transitional year 2023/24) This article explains the entries to make for the 2023/24 transitional year. HMRC's...
	17 Jun, 2026 Views: 7732

	Multi-Factor Authentication for agents being introduced by HMRC. HMRC is introducing Multi-Factor Authentication (MFA) for all tax agent accounts during 2026. The change is designed to improve security and protect...
	16 Jun, 2026 Views: 51

	VAT Filer for agents- How to send to and retrieve data from HMRC What are APIs? HMRC have provided a method of obtaining information relevant to VAT Returns called Application Program Interfaces or APIs. This is...
	16 Jun, 2026 Views: 5490

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	TaxCalc Release Notes 2026 Below are the Release Notes for TaxCalc 2026 releases. Click to see the Release Notes for 2013-2019 > 2020-2024 > 2025 Please note we phase...
	20 May, 2026 Views: 220662

	What is a 1046 authentication error? When you receive a 1046 error message in TaxCalc (as shown above) after attempting to file tax return, it will be due to one of the following: ...
	13 May, 2025 Views: 145329

	Update to refunds made by HMRC On 1st April 2015, HMRC updated their system to change the way they allocate repayments of overpaid tax. HMRC will only process the refund using...
	14 Feb, 2023 Views: 114690

	Useful HMRC links and contact numbers Personal Tax How to pay HMRC – Different ways to pay your Income Tax or Capital Gains Tax Online Services Helpdesk – Help signing up for...
	28 Jun, 2017 Views: 110265

	How do I download TaxCalc? To download and install TaxCalc on a new computer, or update it on a computer that already uses TaxCalc, we recommend viewing our video tutorial...
	25 Oct, 2022 Views: 100562

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