Most landlords run a business without noticing they've started one. Rent arrives (usually), receipts pile up in a drawer, the mortgage leaves on the 1st — and once a year, tax season turns into archaeology. A proper landlord spreadsheet replaces the drawer with a system: every pound in, every pound out, per property, with the tax figures totalling themselves. It's exactly what our Landlord & Rental Property Tracker does in Google Sheets — let's look at what it needs to track and why.
Why landlords outgrow mental maths so fast
One property feels manageable in your head — until it isn't. A boiler repair here, a void month there, an insurance renewal that quietly went up 30%… and suddenly 'the flat makes about £300 a month' is a guess, not a fact. Multiply by two or three properties and the guessing compounds. The spreadsheet's job is to answer three questions instantly, with evidence: Is each property actually profitable? Has everyone paid? What will HMRC need in January? Get those three under control and being a landlord shrinks back into a part-time job.
The six things your spreadsheet must track
1. Rent — due vs received. One row per month per tenancy: due date, amount, date it actually arrived. Late patterns become visible in weeks, not years, and 'has everyone paid this month?' takes one glance.
2. Every expense, categorised. Date, property, category, amount, and a note. The categories should mirror the tax return so January is a copy-paste job, not a puzzle (more below).
3. Tenancy details. Names, start and end dates, deposit amount and protection scheme, rent review dates. The tracker should flag renewals before they sneak up.
4. Compliance dates. Gas safety certificate, EICR, EPC, smoke alarm checks, landlord insurance renewal. These carry real penalties when missed — they belong in the same sheet as the money, with expiry warnings.
5. Occupancy and voids. Every empty week costs a specific number of pounds. Tracking voids per property tells you which ones re-let fast and which need attention (or selling).
6. The profit line. Income minus expenses, per property, per month and year to date — calculated for you, not in your head.
The expense categories that match tax time
Here's a starter set that maps onto a UK self-assessment property page. It follows HMRC's guidance on Your rentals are also usually your biggest wealth line outside a pension — worth watching alongside everything else on the Net Worth Tracker (here's why tracking net worth monthly changes behaviour), with the day-to-day money on the All-in-One Finance Dashboard. First, log the ugly months too. The temptation is to skip recording the £900 boiler month because it 'wasn't typical' — but voids and repairs ARE typical, just lumpy. A property's real profit only shows over twelve honest months, and lenders, accountants and future-you all need the true picture, not the flattering one. Second, reconcile against the bank once a month. Five minutes scanning the statement against the sheet catches the missed rent, the double-charged insurance, and the subscription you forgot the agent added. Small leaks in property finances tend to run for years precisely because nobody is looking — the spreadsheet only protects you if it matches reality. Making Tax Digital for Income Tax changes how many landlords report. GOV.UK's guidance on who needs to use it says that if your qualifying income from property and self-employment was over £50,000 for the 2024 to 2025 tax year, you should have started from 6 April 2026, with the threshold falling to £30,000 from April 2027 and £20,000 from April 2028. Under it you send quarterly updates of your income and expenses as well as the tax return. A spreadsheet can still be your record-keeping system. HMRC's software guidance says that if you use spreadsheets to record income and expenses, bridging software can connect to them and make your submissions, including quarterly updates and your tax return. So the spreadsheet stays; you add compatible bridging software on top. If you are below the threshold, the annual self-assessment return works as before. Check the current rules on GOV.UK, because the dates and thresholds are set by HMRC. The weekly routine, once the sheet exists: mark rent received (10 seconds), log any expenses with a photo of the receipt (a minute each), glance at the compliance panel for anything amber. That's it — five minutes a week, and your totals are ready whenever they are needed, whether that is the annual return or quarterly updates under Making Tax Digital. Build it yourself if you enjoy spreadsheet plumbing, or make a copy of the Landlord & Rental Property Tracker and have the whole system — rent log, categories, tenancies, certificates, per-property dashboard — working before the kettle's boiled. It's also inside the Complete Collection if you want every dashboard we make. Six things per property: rent due vs rent received, every expense by category (mortgage interest, repairs, insurance, agent fees…), tenancy details and renewal dates, safety certificate expiries, occupancy, and the running profit. If it also totals your tax-return figures, tax season becomes an afternoon instead of a fortnight. For many landlords with a handful of properties, a well-built spreadsheet handles the record-keeping. If Making Tax Digital for Income Tax applies to you, you will also need compatible bridging software to send your quarterly updates and return from it. Dedicated property accounting software earns its keep on large portfolios or full agency management, where the volume justifies it. Start with the spreadsheet; you will know soon enough if you outgrow it. Common allowable costs include repairs and maintenance (not improvements), letting agent fees, landlord insurance, ground rent and service charges, accountancy, advertising for tenants, and replacement of domestic items. Relief on mortgage interest and other residential finance costs is restricted to the basic rate of Income Tax (20%) rather than a full deduction. Rules change — confirm with HMRC or an accountant. Gross yield = annual rent ÷ property value × 100. Net yield uses annual rent minus annual costs instead. A £950/month flat worth £180,000 grosses 6.3%; after £3,000 of costs it nets about 4.7%. Tracking it per property shows you which ones actually earn their keep. Log every expense in the spreadsheet the week it happens, with date, property, category and amount — then photograph the receipt into one folder per tax year. The spreadsheet becomes the index, the folder the evidence. Your future self (or accountant) will be grateful. Yes — that's the point. Keep one income/expense log with a property column, then let a dashboard total each property separately and the portfolio overall. That's exactly how our Landlord & Rental Property Tracker is built, so per-property profit is always one glance away.Two habits that make the spreadsheet honest
Making Tax Digital: spreadsheets still work, with one extra step
Set it up once, run it in minutes
Frequently asked questions
What should a landlord spreadsheet track?
Do I really need software, or is a spreadsheet enough?
Which expenses can UK landlords usually claim?
How do I work out rental yield?
How should I organise receipts for tax time?
Can one spreadsheet handle multiple properties?