Landlord Tax Year Planning: A Month-by-Month Checklist

Tax planning shouldn't happen in January when you're scrambling to meet the Self Assessment deadline. Spreading the work across the year makes everything simpler, reduces your bill, eliminates the annual panic, and surfaces planning opportunities you'd otherwise miss. With Making Tax Digital for Income Tax (MTD ITSA) launching for the £50k+ cohort from April 2026, the spread-the-work approach becomes mandatory rather than optional. This guide walks the full UK landlord tax year (6 April year-end basis) month-by-month, with the deadlines, actions, and planning windows that materially affect your tax position.

April: New tax year setup (the highest-leverage month)

The first 30 days of every new tax year are when good landlords win their tax planning. Cheap, fast, high-impact moves:

• Record your CGT base cost. Keep the purchase price, buying costs (such as SDLT and legal fees) and the cost of capital improvements for every property. Market value only matters in special cases, such as an inherited or gifted property.
• Review and update expense categories in Tendmere before using an SA105-aligned summary.
• Set up receipt capture from day 1 — photograph every receipt on the day it arrives. Don't let April backlog accumulate; it always feeds the January panic.
• MTD ITSA threshold check — combined Self-Employment + Property income exceeded £50,000 in 2024/25 → you're in the April 2026 cohort. £30k from April 2027. £20k from April 2028. Sign up via your HMRC personal tax account once eligible.
• Review mortgage deal expiry dates across the portfolio — remortgage planning starts here. 6 months before each fix expires, start engaging a BTL broker.
• Check ISA + pension allowance — tax relief on your own pension contributions is limited to the greater of 100% of your relevant UK earnings (employment or trading income) or £3,600 gross. Rental profit does not count as relevant earnings, so a landlord whose only income is rent cannot get relief on large contributions, even though the annual allowance is £60,000.
• Re-evaluate ownership structure — start of tax year is the cleanest moment to incorporate (transfer to limited company) if you've decided that's right for your portfolio. SDLT + CGT consequences apply; speak to a property-tax accountant first.
• Form 17 — married couples and civil partners are taxed 50:50 on jointly owned property by default. If you genuinely own it in unequal shares, you can declare this on Form 17, which must reach HMRC within 60 days of the date of the declaration. It reflects actual ownership: you cannot simply choose an income split. It continues to apply until your ownership shares change.

May–June: Q1 operational + financial review

• Review Q1 income + expenses — are you tracking everything? Spot-check 5 random transactions for correct categorisation.
• MTD quarterly deadline (if applicable): confirm the current period and deadline in your HMRC account or with your accountant. Tendmere can prepare recorded figures for review but does not submit them in production.
• Insurance renewals due May–June for many policies — shop around. Loyalty premium creep is real on landlord lines.
• Schedule annual Gas Safety inspections for properties whose certificates expire June–September.
• Replenish maintenance reserve (1% of property value/year) — start of the financial year is when most landlords have spare cash from the prior year's surplus.
• Re-evaluate any property approaching the EPC deadline — book remediation work in summer when contractors have capacity.

July–September: Mid-year planning + first payment on account

• 31 July: Second payment on account due for prior tax year (if you're in Self Assessment with payments-on-account enabled). Failure to pay attracts daily interest at HMRC rate (currently 7.75%).
• MTD Q1 submission deadline: 7 August. If you're in the cohort, your Q1 figures must be in HMRC by this date.
• Review rent levels against current market evidence and plan any Form 4A notice around the tenancy's first-year and once-per-year restrictions.
• MTD Q2 covers 6 July – 5 October: figures need to be in HMRC by 7 November.
• Plan any property improvements that affect EPC rating (insulation, glazing, heating) — book contractors before the autumn rush starts in late September.
• Book your accountant's time for the autumn-winter cycle. Property-tax accountants get fully booked from October; the January slot is gone by November in most firms.
• Mid-year P&L review — generate the year-to-date report from Tendmere. Compare actual income + expenses against your annual plan; adjust the H2 plan if needed.
• Pension contributions — fiscal-year-end pension planning runs alongside personal tax planning; if you're hitting higher-rate income with rental income on top, review pension contribution capacity now.

October–November: Pre-year-end optimisation window

The window where most year-end tax planning actually happens. By December, decisions need to be locked in.

• 5 October: Self Assessment registration deadline if this is your first year with rental income. Late registration = penalty + interest.
• Bring forward planned repairs and maintenance into this tax year — they're immediately deductible. Anything you've been putting off (boiler service, repaint, garden landscaping) — schedule before 5 April.
• Review mortgage interest for the year — ensure it's correctly recorded for the Section 24 tax credit calculation. Lender annual statements arrive November–February; chase them if delayed.
• Check you've captured all allowable expenses: travel (mileage log), professional fees, insurance, agent fees, software subscriptions, accountancy fees, mobile phone share, home office allowance, replacement of domestic items.
• 31 October: Paper Self Assessment filing deadline. Almost no one files paper anymore — but if you do, this is the date.
• 7 November: MTD Q2 submission deadline (if applicable). Q2 = 6 July – 5 October.
• Consider timing of property sales — can you use your annual CGT exemption (£3,000 from 2024/25) before 5 April? Joint owners can use both.
• Review your dividend tax position if you operate via a limited company. Optimal extraction often involves balancing salary + dividends to use Personal Allowance + dividend allowance + basic-rate band efficiently.
• Charity giving via Gift Aid extends basic-rate band — useful for higher-rate landlords approaching the Personal Allowance taper threshold (£100k).

December: Final pre-year-end actions

• Reconcile the year so far — generate the YTD report from Tendmere. Verify rent + expense totals against your bank statements.
• If you have repairs planned (such as a like-for-like boiler replacement), think about the timing so the cost lands in the tax year you intend. Capital improvements are not deductible from rent whenever you pay for them.
• Pension top-up — if you have relevant earnings and are making a pension contribution to reduce higher-rate tax, do it before 5 April. Late February to mid-March is the practical window after the Christmas pause.
• Review Form 17 if you own property jointly with a spouse or civil partner and your ownership shares have changed.

January–March: Filing season + new year planning

• 31 January: Self Assessment filing deadline + balancing payment due + first payment on account for next year. Late filing = £100 penalty rising to £900+ over time.
• Generate your SA105 report from Tendmere and send it to your accountant. To file, use HMRC-recognised compatible software; Tendmere’s production filing is not enabled.
• Pay any tax owed — set aside rental income throughout the year so this isn't a shock. Most landlords miss this and end up paying via credit card or borrowing.
• 7 February: MTD Q3 submission deadline (if applicable). Q3 = 6 October – 5 January.
• 5 April: End of tax year. Last day for: capital expenditure to land in this year, pension contributions for this year's allowance, CGT exemption use, ISA contributions, charity Gift Aid carry-back.
• After 5 April: start the next year's planning at April again. The cycle compounds — landlords who plan in April pay materially less tax than landlords who plan in December.

Year-round good habits

• Log expenses as they happen — not in a batch at year-end. Tendmere's receipt OCR makes the same-day capture trivial (photograph + done).
• Photograph receipts immediately. Paper receipts fade; digital is permanent.
• Keep a mileage log for property visits — recorded contemporaneously, not estimated at year-end. HMRC have rejected reconstructed logs in enquiries.
• Reconcile your rental bank account monthly, entering payments or importing a CSV statement (Tendmere’s bank feed is not live). End-of-month visibility lets you catch issues early.
• Keep tenant + tenancy + compliance documents in one place — the documents vault in Tendmere does this with full audit trail.
• File certificates as they expire — Gas Safety, EICR, EPC, deposit-protection records — so your year-end review is fast.
• Quarterly accountant check-in — a 30-minute call every 3 months catches issues that a January-only review misses.

Key dates quick-reference

• 5 April — End of tax year
• 6 April — Start of new tax year
• 5 October — SA registration deadline for new landlords
• 31 October — Paper SA filing deadline
• 31 January — Online SA filing deadline + balancing payment + first payment on account
• 31 July — Second payment on account
• 7 August / 7 November / 7 February / 7 May — MTD ITSA quarterly submission deadlines
• 31 January (for those in MTD) — Tax return (final declaration) for the previous tax year, submitted through MTD-compatible software

Common tax-planning misses

• Not claiming home office allowance — £6/week (£312/year) flat-rate or actual costs, allowable for time spent administering the rental business from home
• Not claiming mileage — 45p/mile up to 10,000 miles, 25p thereafter, for property visits (not commuting)
• Getting joint ownership wrong — not using Form 17 where you genuinely own a property in unequal shares, or trying to use it to shift income without changing ownership
• Treating capital improvements as revenue expenses — a like-for-like kitchen replacement is a deductible repair, but an upgrade to a higher specification is capital. Get the categorisation right or face HMRC enquiry on a discovery basis
• Forgetting Replacement of Domestic Items Relief — like-for-like white goods replacement is fully deductible against rental profit
• Missing the Property Allowance — first £1,000 of property income is tax-free if you choose; doesn't make sense for most landlords because you can't then claim expenses, but useful for very low-income lets
• Missing Rent-a-Room relief — £7,500 tax-free if letting a room in your own home (not relevant to standard BTL but catches some landlord-occupiers out)
• Not including all expense categories on the SA105 — accountancy fees, software subscriptions, insurance, mortgage arrangement fees, professional indemnity

Related guides

• Making Tax Digital for landlords (pillar)
• Landlord allowable expenses (pillar)
• Section 24 mortgage interest relief explained
• Landlord record keeping
• How Tendmere prepares MTD records

HMRC dates + thresholds change. Verify the live position at gov.uk/self-assessment-tax-returns + GOV.UK: Making Tax Digital for Income Tax for your specific tax year.