Uk Income Tax Sa100

UK Income Tax (SA100) -- Individual Tax Computation Skill v2.1

General reference only. This skill is general tax/accounting reference material for AI-assisted workflows. It has not been reviewed for any specific person's facts, documents, elections, deadlines, residency, filing status, or local procedures. Do not rely on it to file, pay, amend, or take a tax position without review by a qualified professional in the relevant jurisdiction.

This skill covers three tax years in parallel:

• Prior year: 2024-25 (6 April 2024 -- 5 April 2025) -- filed by 31 January 2026
• Current year: 2025-26 (6 April 2025 -- 5 April 2026) -- filed by 31 January 2027
• From 6 April 2026: 2026-27 (6 April 2026 -- 5 April 2027) -- filed by 31 January 2028

All headline income tax rates and thresholds are frozen through 2027-28. The Autumn Budget 2025 announced targeted rate increases on investment income (dividends, savings, property) effective 6 April 2026 -- see Section 1.5.

Section 1 -- Quick Reference

1.0 Three-Year Comparison -- Headline rUK Bands (FROZEN through 2027-28) [T1]

Source: Personal allowance and higher rate threshold freeze extended to 5 April 2028 (Finance (No. 2) Act 2023 s.5; Autumn Budget 2025 confirmed no further extension at this stage, but the freeze through 2027-28 remains in force).

1.1 Income Tax Bands -- England, Wales, Northern Ireland (rUK) -- 2024-25 [T1]

1.2 Income Tax Bands -- rUK -- 2025-26 [T1]

1.3 Income Tax Bands -- rUK -- 2026-27 (from 6 April 2026) [T1]

Headline rates and thresholds are unchanged from 2025-26 -- the freeze continues through 2027-28. Autumn Budget 2025 changes are confined to investment income (see Section 1.5).

1.4 Scottish Income Tax Bands [T1]

Scottish bands are set annually by the Scottish Parliament (Scotland Act 2016) and are independent of the rUK schedule. They apply ONLY to non-savings, non-dividend income. Savings and dividends always use UK-wide rates.

Scottish Bands 2024-25

Scottish Bands 2025-26

Scottish Bands 2026-27

TBC -- Scottish Budget 2025-26 not yet enacted at time of writing. The Scottish Government typically announces rates in December for the following April. Verify against the Scottish Rate Resolution before finalising any 2026-27 computation. Until then, apply 2025-26 bands as a working estimate and flag for reviewer.

1.5 Changes from April 2026 -- Autumn Budget 2025 [T1]

Effective 6 April 2026, the following changes take effect under measures announced in the Autumn Budget 2025 (Finance (No. 2) Bill 2024-26 / Finance Bill 2026, pending Royal Assent):

Key points:

• Dividend rates -- confirmed 2pp uplift on ordinary and upper rates from 6 April 2026. See companion skill uk-dividends for the detailed dividend computation, the GBP 500 allowance interaction, and worked examples.
• Savings income and property income -- the Autumn Budget 2025 announced changes aligning these income streams more closely with the dividend treatment, expected to be a 2pp uplift on basic and higher rate bands (no change at additional rate). TBC -- verify against Finance (No. 2) Bill 2024-26 / Finance Bill 2026 once enacted. Do not finalise a 2026-27 computation involving material savings or property income until the rates are confirmed. Flag for reviewer.
• HICBC -- the GBP 60,000 starting / GBP 80,000 full claw-back tapered threshold introduced from 2024-25 remains in force for 2026-27 (no further reform announced).
• All other bands frozen -- Personal Allowance (GBP 12,570), basic rate threshold (GBP 50,270), additional rate threshold (GBP 125,140), and PA taper threshold (GBP 100,000) are all frozen through 2027-28.

Key Allowances and Thresholds [T1]

Dividend Rates [T1]

See companion skill uk-dividends for full dividend-specific guidance, including the GBP 500 allowance, scrip dividends, and overseas dividend treatment.

Conservative Defaults [T1]

Section 2 -- Required Inputs and Refusal Catalogue

Required Inputs

Minimum viable -- P60 (employment income), self-employment profit from SA103, and confirmation of residency status and Scottish taxpayer status.

Recommended -- P11D (benefits in kind), bank interest certificates, dividend vouchers, pension contribution statements, Gift Aid records, prior year SA302 (tax calculation).

Ideal -- all supplementary pages (SA103, SA105, SA106), complete records of all income sources, prior year payments on account made.

Refusal Catalogue

R-UK-IT-1 -- Non-resident or split-year treatment. "Non-resident and split-year cases have different rules and may involve the remittance basis. Out of scope. Escalate."

R-UK-IT-2 -- Non-domiciled individuals. "The remittance basis for non-doms requires specialist advice. Out of scope." (Note: the remittance basis is abolished from 6 April 2025 and replaced by a residence-based regime -- escalate any post-April-2025 non-dom queries.)

R-UK-IT-3 -- Trust income. "Income from trusts (SA107) has specific rules. Out of scope."

R-UK-IT-4 -- Complex pension annual allowance. "Tapered annual allowance, money purchase annual allowance, and carry-forward calculations beyond basic require specialist review. Escalate."

R-UK-IT-5 -- Capital gains. "Capital gains are computed separately on SA108. This skill covers income tax only."

R-UK-IT-6 -- 2026-27 savings/property rate finalisation. "The Autumn Budget 2025 announced rate changes to savings and property income from 6 April 2026 but the specific rates are pending Finance Bill enactment. Do not finalise a 2026-27 return involving material savings or property income until the Finance Bill receives Royal Assent. Flag for reviewer."

Section 3 -- Transaction Pattern Library

For SA100, the "transactions" are not bank statement lines but rather income items from various sources flowing into the tax computation. This pattern library maps income types to the correct SA100 section and tax treatment.

3.1 Employment Income Patterns

3.2 Self-Employment Income Patterns

3.3 Savings Income Patterns

3.4 Dividend Income Patterns

3.5 Pension Income Patterns

3.6 Pension Contribution Patterns (Deductions)

3.7 Other Income Patterns

Section 4 -- Worked Examples

Each scenario is repeated across all three years so reviewers can see the year-on-year effect of the rate freeze and the April 2026 changes.

Example 1 -- Basic Rate Taxpayer (Employment Only)

Input: Employment GBP 35,000. PAYE deducted GBP 4,486. No other income.

Computation (identical for 2024-25, 2025-26, and 2026-27 -- bands frozen):

• Personal allowance: GBP 12,570
• Taxable income: 35,000 - 12,570 = GBP 22,430
• Tax: 22,430 x 20% = GBP 4,486
• Less PAYE: GBP 4,486
• Balance: GBP 0

Note: Because no investment income is involved and headline bands are frozen, the computation is identical across all three years.

Example 2 -- Employment + Self-Employment + Dividends

Input: Employment GBP 40,000 (PAYE GBP 5,486). Self-employment profit GBP 20,000. Dividends GBP 5,000.

2024-25 computation

• Total income: GBP 65,000
• Personal allowance: GBP 12,570
• Taxable: GBP 52,430
• Non-savings (GBP 60,000 - 12,570 = GBP 47,430): 37,700 x 20% = GBP 7,540. Remaining 9,730 x 40% = GBP 3,892.
• Dividends (GBP 5,000 -- all in higher rate band): 500 at 0% (dividend allowance) + 4,500 x 33.75% = GBP 1,518.75
• Total tax: 7,540 + 3,892 + 1,518.75 = GBP 12,950.75
• Less PAYE: GBP 5,486
• Balance via SA: GBP 7,464.75

2025-26 computation

• Identical to 2024-25 (no rate or threshold changes). Total tax GBP 12,950.75.

2026-27 computation

• Non-savings tax unchanged: 7,540 + 3,892 = GBP 11,432
• Dividends at new rates: 500 at 0% + 4,500 x 35.75% = GBP 1,608.75
• Total tax: 11,432 + 1,608.75 = GBP 13,040.75
• Increase vs 2025-26: GBP 90.00 (entirely from the 2pp dividend uplift on the GBP 4,500 chargeable above the allowance)

(Class 4 NIC on self-employment is computed in the SA103 skill -- see uk-self-employment-sa103.)

Example 3 -- Personal Allowance Taper

Input: Total income GBP 115,000. GBP 10,000 gross pension contribution (relief at source).

Computation (identical for 2024-25, 2025-26, and 2026-27 -- PA taper threshold frozen at GBP 100,000):

• Adjusted net income: 115,000 - 10,000 = GBP 105,000
• PA reduction: (105,000 - 100,000) / 2 = GBP 2,500
• Personal allowance: 12,570 - 2,500 = GBP 10,070
• Basic rate band extended by pension: 37,700 + 10,000 = GBP 47,700
• Higher rate threshold: 10,070 + 47,700 = GBP 57,770

Example 4 -- Scottish Taxpayer with Savings

Input: Scottish taxpayer. Employment GBP 50,000. Bank interest GBP 3,000.

2024-25 computation

• Non-savings (Scottish 2024-25 rates): 50,000 - 12,570 = GBP 37,430 taxable
  • Starter (2,306): 19% = GBP 438.14
  • Basic (11,685): 20% = GBP 2,337.00
  • Intermediate (17,101 -- up to 43,662-12,570=31,092): 21% = GBP 3,591.21
  • Higher (37,430 - 31,092 = 6,338): 42% = GBP 2,661.96
• Savings (UK rates): GBP 3,000 -- taxpayer is higher rate
  • PSA: GBP 500 at 0%
  • Remaining: GBP 2,500 at 40% = GBP 1,000
• Total: 9,028.31 + 1,000 = GBP 10,028.31

2025-26 computation

• Non-savings (Scottish 2025-26 rates -- starter and basic bands slightly wider): 50,000 - 12,570 = GBP 37,430 taxable
  • Starter (2,827): 19% = GBP 537.13
  • Basic (12,094): 20% = GBP 2,418.80
  • Intermediate (16,171 -- up to 43,662-12,570=31,092): 21% = GBP 3,395.91
  • Higher (37,430 - 31,092 = 6,338): 42% = GBP 2,661.96
• Savings (UK rates): GBP 3,000 -- taxpayer is higher rate
  • PSA: GBP 500 at 0%
  • Remaining: GBP 2,500 at 40% = GBP 1,000
• Total: 9,013.80 + 1,000 = GBP 10,013.80

2026-27 computation

• Non-savings (Scottish 2026-27 rates -- TBC pending Scottish Budget; using 2025-26 as working estimate): GBP 9,013.80 (same as 2025-26 estimate)
• Savings (UK rates -- TBC pending Finance Bill 2026): GBP 3,000 -- taxpayer is higher rate
  • PSA: GBP 500 at 0% (assumed unchanged)
  • Remaining: GBP 2,500 at expected 42% = GBP 1,050 (vs GBP 1,000 in 2025-26)
• Estimated total: 9,013.80 + 1,050 = GBP 10,063.80 (TBC -- flag for reviewer; do not finalise until Finance Bill enacted)

Example 5 -- Marriage Allowance

Input: Spouse A income GBP 10,000. Spouse B income GBP 28,000 (basic rate). Election made.

Computation (identical for 2024-25, 2025-26, and 2026-27 -- marriage allowance frozen at GBP 1,260 / reducer GBP 252):

• Spouse A: PA reduced to GBP 11,310. Income GBP 10,000 < GBP 11,310. Tax = GBP 0.
• Spouse B: Tax = (28,000 - 12,570) x 20% = GBP 3,086. Less marriage allowance reducer GBP 252. Tax = GBP 2,834.

Example 6 -- HICBC (2024-25 reform onwards, applies in 2025-26 and 2026-27)

Input: Higher earner adjusted net income GBP 70,000. Child benefit received GBP 2,212.60 (one child, full year).

Computation (identical for 2024-25, 2025-26, and 2026-27 -- HICBC threshold frozen at GBP 60,000 / GBP 80,000):

• ANI in taper zone: GBP 70,000 (between GBP 60,000 and GBP 80,000)
• Excess over GBP 60,000: GBP 10,000
• Charge percentage: 10,000 / 200 = 50%
• HICBC: 2,212.60 x 50% = GBP 1,106.30
• Added to tax due via SA100

Section 5 -- Tier 1 Rules (When Data Is Clear)

5.1 Income Ordering [T1]

Legislation: ITA 2007, ss 6-22

Mandatory order: (1) Non-savings income fills bands first. (2) Savings income next. (3) Dividends on top. This ordering is required by law and affects which rates apply. The ordering rule is unchanged in 2026-27 -- only the rates on savings and dividends change.

5.2 Personal Allowance [T1]

GBP 12,570 across all three years (2024-25, 2025-26, 2026-27 -- frozen through 2027-28). Tapers at GBP 1 for every GBP 2 above GBP 100,000 adjusted net income. Fully withdrawn at GBP 125,140. Effective 60% marginal rate in taper zone.

Adjusted net income = Total income - gross pension contributions - grossed-up Gift Aid.

5.3 Savings Allowance and Starting Rate [T1]

Personal savings allowance: GBP 1,000 (basic rate), GBP 500 (higher rate), GBP 0 (additional rate). Starting rate for savings: GBP 5,000 at 0%, reduced by GBP 1 for each GBP 1 of non-savings income above PA.

2026-27: Allowance amounts are expected to remain unchanged, but the rates applied to savings income above the allowance are TBC pending Finance Bill 2026 enactment (Autumn Budget 2025 announced an expected 2pp uplift on basic and higher bands).

5.4 Dividend Allowance [T1]

GBP 500 at 0% rate (unchanged across all three years). Uses up the basic rate band -- it is NOT a deduction from income.

Dividend rates above the allowance:

• 2024-25 and 2025-26: 8.75% / 33.75% / 39.35%
• 2026-27: 10.75% / 35.75% / 39.35%

See uk-dividends for the full dividend treatment.

5.5 Marriage Allowance [T1]

Transfer GBP 1,260 from spouse with income below PA to basic-rate spouse. Reducer = GBP 252 (always at 20%, even for Scottish taxpayers). Recipient must NOT be higher/additional rate. Unchanged across all three years.

5.6 Basic Rate Band Extension [T1]

Extended by: gross pension contributions (relief at source) + grossed-up Gift Aid donations. Example: GBP 4,000 gross pension = basic rate band becomes GBP 41,700. Unchanged across all three years.

5.7 Payments on Account [T1]

Required if prior year SA liability > GBP 1,000 AND less than 80% deducted at source. POA1: 31 January (50% of prior year). POA2: 31 July (50%). Balance: 31 January following year. Mechanism unchanged across all three years.

5.8 Filing and Penalties [T1]

Online deadlines:

• 2024-25 return: 31 January 2026
• 2025-26 return: 31 January 2027
• 2026-27 return: 31 January 2028

Late filing: GBP 100 immediate, then GBP 10/day after 3 months, then 5% of tax at 6 and 12 months. Late payment: 5% at 30 days, 6 months, 12 months.

5.9 High Income Child Benefit Charge (HICBC) [T1]

Applies from 2024-25 onwards with a tapered range of GBP 60,000 to GBP 80,000 adjusted net income (reform enacted by Finance Act 2024). Charge = 1% of child benefit for every GBP 200 of income between GBP 60,000 and GBP 80,000. At GBP 80,000+: 100% claw-back. Thresholds unchanged in 2025-26 and 2026-27.

Section 6 -- Tier 2 Catalogue (Reviewer Judgement Required)

6.1 Personal Allowance Taper Planning [T2]

Pension contributions and Gift Aid can reduce adjusted net income below GBP 100,000 to restore the PA. Legitimate planning strategy. Flag for reviewer to confirm contribution amounts are within annual allowance.

6.2 High Income Child Benefit Charge -- Cross-Year Planning [T2]

For taxpayers in the GBP 60,000-80,000 taper zone, the effective marginal rate including HICBC can exceed 60%. Cross-year planning (timing of bonus income, pension contributions to reduce ANI) is materially valuable. Flag for reviewer.

6.3 Reducing Payments on Account [T2]

Client can apply (SA303) to reduce POAs if they expect lower liability. If estimate is too low, HMRC charges interest from original due date. Flag before reducing. For the 2025-26 -> 2026-27 transition, POAs for 2026-27 will be based on 2025-26 liability -- consider whether the 2026-27 dividend/savings rate increases will materially raise the actual liability above POA estimates.

6.4 Pension Annual Allowance [T2]

GBP 60,000 standard. Tapers to GBP 10,000 for adjusted income over GBP 260,000. 3-year carry forward of unused allowance available. Excess triggers annual allowance charge at marginal rate. Flag for specialist review if near limits.

6.5 Multiple Income Sources Band Allocation [T2]

When savings and dividends push income across rate band boundaries, the interaction of PSA, dividend allowance, and band extensions can be complex. Flag for reviewer to verify computation. Especially important for 2026-27 given the divergence of dividend, savings, and non-savings rates.

6.6 2026-27 Savings and Property Income Rate Confirmation [T2]

The Autumn Budget 2025 announced rate increases on savings and property income from 6 April 2026, expected to mirror the 2pp uplift on basic and higher bands. The specific rates are TBC pending Finance (No. 2) Bill 2024-26 / Finance Bill 2026 enactment. Flag any 2026-27 return with material savings or property income for reviewer; do not finalise until rates are confirmed in legislation.

Section 7 -- Excel Working Paper Template

SA100 TAX COMPUTATION -- Tax Year [SELECT: 2024-25 / 2025-26 / 2026-27]

A. INCOME
  A1. Employment income (P60 gross)                ___________
  A2. Benefits in kind (P11D)                      ___________
  A3. Self-employment profit (from SA103)          ___________
  A4. Savings income (bank interest)               ___________
  A5. Dividend income                              ___________
  A6. Pension income                               ___________
  A7. Property income (from SA105)                 ___________
  A8. Other income                                 ___________
  A9. TOTAL INCOME                                 ___________

B. DEDUCTIONS FROM TOTAL INCOME
  B1. Trading losses (sideways relief)             ___________
  B2. Gross pension contributions (for ANI)        ___________
  B3. Gift Aid (grossed up, for ANI)               ___________
  B4. Adjusted net income                          ___________

C. PERSONAL ALLOWANCE
  C1. Standard PA                                  12,570
  C2. Taper reduction (if ANI > 100,000)           ___________
  C3. Available PA                                 ___________

D. TAXABLE INCOME
  D1. Non-savings taxable                          ___________
  D2. Savings taxable                              ___________
  D3. Dividend taxable                             ___________
  D4. Total taxable                                ___________

E. TAX COMPUTATION
  E1. Tax on non-savings (rUK or Scottish)         ___________
  E2. Tax on savings (with PSA + starting rate)    ___________
       Rates: 2024-25 & 2025-26 = 20/40/45
              2026-27 = TBC (expected 22/42/45)    [FLAG]
  E3. Tax on dividends (with allowance)            ___________
       Rates: 2024-25 & 2025-26 = 8.75/33.75/39.35
              2026-27 = 10.75/35.75/39.35
  E4. Total income tax                             ___________
  E5. Less: tax reducers (MA, EIS, etc.)           ___________
  E6. Income tax charged                           ___________
  E7. Plus: HICBC (if ANI > 60,000)                ___________
  E8. Less: PAYE deducted                          ___________
  E9. Less: tax on savings at source               ___________
  E10. Less: payments on account                   ___________
  E11. TAX DUE / (REFUND)                          ___________

F. CLASS 4 NIC (from SA103)                        ___________

G. TOTAL DUE (E11 + F)                             ___________

REVIEWER FLAGS:
  [ ] Tax year selected and applied consistently?
  [ ] Scottish or rUK rates confirmed?
  [ ] PA taper checked?
  [ ] Income ordering correct (non-savings > savings > dividends)?
  [ ] Marriage allowance eligibility verified?
  [ ] HICBC computed if ANI > 60,000?
  [ ] For 2026-27: dividend rates updated to 10.75/35.75/39.35?
  [ ] For 2026-27: savings/property rates confirmed against enacted Finance Bill 2026?
  [ ] All T2 items flagged?

Section 8 -- Bank Statement Reading Guide

SA100 is primarily compiled from official documents (P60, P11D, interest certificates, dividend vouchers) rather than raw bank statements. However, bank statements may be needed to identify:

Section 9 -- Onboarding Fallback

If the client cannot provide all documents immediately:

1. Confirm which tax year(s) the engagement covers (2024-25, 2025-26, and/or 2026-27)
2. Start with P60 and any SA103 computation
3. Ask for bank statements to identify savings interest and dividends
4. Apply conservative defaults
5. Generate working paper with flags
6. Present questions:

ONBOARDING QUESTIONS -- UK INCOME TAX (SA100)
0. Which tax year? (2024-25 prior / 2025-26 current / 2026-27 from April 2026)
1. Are you a Scottish taxpayer? (main residence in Scotland)
2. Employment income -- do you have your P60 and P11D?
3. Self-employment -- have you completed your SA103?
4. Bank interest received in the year?
5. Dividends received in the year?
6. Pension income (state and/or private)?
7. Rental income?
8. Pension contributions made (personal, not workplace)?
9. Gift Aid donations made?
10. Married/civil partner -- is marriage allowance being claimed?
11. Payments on account already made for the year?
12. PAYE tax deducted (from P60)?
13. Child benefit received? (HICBC if ANI > GBP 60,000)

Section 10 -- Reference Material

Key Legislation

PROHIBITIONS

• NEVER compute tax without first confirming the tax year (2024-25, 2025-26, or 2026-27)
• NEVER apply 2025-26 dividend rates to a 2026-27 computation (the ordinary and upper rates change to 10.75% and 35.75%)
• NEVER finalise a 2026-27 return with material savings or property income before Finance Bill 2026 receives Royal Assent -- flag TBC
• NEVER compute tax without categorising income as non-savings, savings, or dividends
• NEVER apply Scottish rates to savings or dividend income
• NEVER apply marriage allowance if recipient is higher/additional rate
• NEVER ignore PA taper for adjusted net income above GBP 100,000
• NEVER apply PSA to additional rate taxpayers (it is GBP 0)
• NEVER treat dividend allowance as a deduction -- it is a 0% rate band
• NEVER apply starting rate for savings if non-savings income exceeds GBP 17,570
• NEVER compute POAs based on current year -- always prior year SA liability
• NEVER advise on non-domiciled or remittance basis -- escalate
• NEVER present tax calculations as definitive -- always label as estimated

Disclaimer

This skill and its outputs are provided for informational and computational purposes only and do not constitute tax, legal, or financial advice. Open Accountants and its contributors accept no liability for any errors, omissions, or outcomes arising from the use of this skill. All outputs must be reviewed and signed off by a qualified professional (such as a CPA, EA, tax attorney, or equivalent licensed practitioner in your jurisdiction) before filing or acting upon.

The 2026-27 figures in this skill reflect the Autumn Budget 2025 announcements as at the version date. Items flagged "TBC" are pending the enactment of Finance (No. 2) Bill 2024-26 / Finance Bill 2026 and must be reconfirmed against the final legislation before filing.

The most up-to-date, verified version of this skill is maintained at openaccountants.com. Log in to access the latest version, request a professional review from a licensed accountant, and track updates as tax law changes.

Source: OpenAccountants — open tax Guides for AI, reviewed by named CPAs/CAs/EAs. Quality: source-cited draft. For always-current figures and named-accountant backing, connect the OpenAccountants MCP server (openaccountants-mcp).