2026/27 multi-income planning estimate
Self Assessment Tax Return Calculator UK
Bring several common Self Assessment income sources into one estimate: self-employed profit, employment or other non-dividend income, taxable rental profit and dividends. Then compare the estimated liability with tax already paid.
Enter gross taxable income before PAYE tax. Do not add dividends here.
Use property profit after the relevant expense/allowance method, not gross rent.
For example, PAYE Income Tax or relevant amounts already paid. Do not guess future payments on account here.
Worked example: employment plus freelance, property and dividends
Sam has £30,000 of employment and other non-dividend income. A freelance activity makes £25,000 turnover with £5,000 allowable expenses, so self-employed profit is £20,000. Sam also has £4,000 taxable rental profit and £2,000 dividends. Total income in the simplified estimate is £56,000.
On the calculator's 2026/27 assumptions, non-dividend Income Tax is £9,032, dividend tax is £536.25 and Class 4 National Insurance is £445.80, giving an estimated £10,014.05 liability before tax already paid. If £3,500 has already been paid through PAYE or relevant credits, the simplified amount still due is £6,514.05. Payments on account are a separate next-step calculation.
Practical calculator guidance
Using the return estimate as a cross-check
A Self Assessment return brings together taxable income, allowable deductions and tax already paid. This calculator can test a straightforward scenario, but the filed return must reflect all relevant sources and claims rather than only the largest business figure.
Prepare an income-source checklist first
Gather employment forms, self-employment accounts, property records, dividends, savings interest, pensions and other taxable amounts that apply. Avoid counting transfers between accounts as income or omitting a platform because it paid into a separate wallet. The correct return pages and supplementary sections depend on the source, not merely the payment method.
Separate reliefs from ordinary expenses
Trading expenses, property expenses, pension contributions, Gift Aid and losses can affect a calculation in different ways. One generic deduction field cannot reproduce every rule. Keep supporting schedules and use HMRC software or compatible commercial software for the actual return. Check tax already deducted through PAYE, CIS or other routes so it is not paid twice.
File early enough to resolve questions
Online returns are normally due by 31 January following the tax year, with earlier deadlines for paper returns. Registration can also be required. Filing early does not usually bring the standard payment deadline forward, but it provides time to understand the calculation, arrange cash and correct missing information. Save the submission receipt and final calculation.
Worked example
A freelancer prepares £28,000 of turnover and £4,500 of supported costs, plus a P60 showing earlier employment and PAYE deducted. They calculate provisional trading profit, enter each source in the appropriate return section and credit the PAYE already paid. The calculator helps check scale, but the HMRC calculation determines the filed liability and whether payments on account apply.
Related calculators and guides
How this guidance is reviewed
Author
Written and maintained by UK Tax Toolbox, led by founder Conor Dwyer. Calculator assumptions are checked against the public sources linked on the page.
Last reviewed
12 August 2026
Basis of guidance
Public HMRC and GOV.UK guidance, published tax thresholds and the calculator assumptions stated on each page.
Useful official references
Spot something that looks out of date? Use the contact page to flag corrections. Important tax decisions should still be checked with HMRC or a qualified adviser.