Free property tools and calculators for UK landlords 2026

Running a rental business in 2026 means staying on top of the numbers, and the numbers have rarely been more demanding: higher financing costs, tighter affordability tests, a shifting compliance regime and, since April 2026, Making Tax Digital for higher-earning landlords. To take some of the guesswork out, August offers a suite of free calculators built specifically for UK landlords. They are quick, accurate and mobile-friendly, they need no sign-up, and they live in one place at augustapp.com/calculators. This guide explains what each tool does and when to reach for it, so you can pick the right one rather than scrolling the whole list.

Why these tools matter

The last few years have reshaped buy-to-let. It remains a sound investment for many, but it is no longer an easy win, and the margin between a good deal and a poor one is often a calculation away. Rather than guess, you can test real figures: what a half-point rise in rates does to your cash flow, how much stamp duty a purchase attracts, or whether an applicant’s income comfortably covers the rent. The calculators below answer those questions in seconds, and grouping them the way the tool hub does, by investment, tax, day-to-day operations and the more complex deals, makes it easier to find the one you need.

Research a location

Postcode property checker

Before anything else comes research. The postcode property checker takes any UK postcode and returns local authority data, compliance flags, environmental risks such as flooding, and nearby amenities. It is the fastest way to learn whether a property sits in a selective licensing area or a flood-risk zone before you commit, work that would otherwise take hours.

Investment tools

Rental yield calculator

Yield is the bedrock of buy-to-let. The rental yield calculator takes a purchase price and expected rent and returns gross and net yield, so you can screen deals side by side: a 6% yield against a 4.2% one is an immediate signal. If you want the concept behind the number first, our explainer on what rental yield is sets it out.

Rental cash flow calculator

Yield alone does not tell the whole story. The rental cash flow calculator models monthly and annual cash flow after mortgage payments, management fees, maintenance, insurance and void periods, and shows your breakeven rent. It is what stops you buying a property that looks fine on paper but loses money once the real costs are in.

Buy-to-let mortgage calculator

For most landlords, finance is the largest single cost. The buy-to-let mortgage calculator lets you test deposit, term, rate and mortgage type, compare interest-only against capital and interest, and see your monthly payment, total cost and loan-to-value, which is the figure lenders judge affordability against.

Tax tools

Buy-to-let stamp duty calculator

Transaction costs matter, and Stamp Duty Land Tax is among the largest. The stamp duty calculator reflects the rules now in force, including the 5% additional-dwelling surcharge and the £125,000 nil-rate threshold, the surcharge for non-residents, and the regional differences across England, Scotland, Wales and Northern Ireland, as confirmed in HMRC’s stamp duty guidance. It is most useful when weighing different price brackets or buying through a company. For the background, our guide to the 2025 stamp duty changes explains how the current rules came about.

Landlord mileage calculator

Trips to your properties for inspections, viewings and overseeing works are an allowable expense. The landlord mileage calculator applies the official HMRC mileage rate to your journeys and produces a clear, recordable figure. For 2026/27 that rate is 55p per mile for the first 10,000 business miles and 25p thereafter, an increase from the long-standing 45p that took effect from 6 April 2026, which makes logging your mileage more worthwhile than ever.

Rental income tax and Making Tax Digital calculator

Making Tax Digital has applied to landlords with qualifying income above £50,000 since April 2026, and keeping on top of what you will owe is half the battle. The rental income tax calculator estimates your property profit and income tax, shows your indicative Making Tax Digital start year, and gives illustrative quarterly figures and payments on account. It is a quick way to sanity-check a tax position for budgeting or a conversation with a lender or accountant.

Multiple dwellings relief calculator

Buying two or more units in a single transaction can change your stamp duty, and the rules are fiddly. The multiple dwellings relief calculator estimates SDLT with and without the relief, shows the average price per dwelling, applies the minimum floor where it bites, and highlights any saving, which is useful when reviewing multi-unit or annexe deals with a broker or conveyancer.

Day-to-day operations tools

Pro-rata rent calculator

When a tenant moves in or out mid-month, working out the right rent is easy to get wrong. The pro-rata rent calculator takes the monthly rent, the due day and the actual move date and returns exactly what to charge or refund, which keeps the arithmetic fair and transparent and heads off disputes.

Rent affordability calculator

Before offering a tenancy, you want confidence the applicant can afford it. The rent affordability calculator checks a tenant’s gross income against the rent using the common rent-to-income ratio. It is a first screen rather than a substitute for full referencing, but it lowers the risk of arrears later.

Weekly to monthly rent calculator

Not all rent is paid monthly. The weekly to monthly rent calculator converts instantly between weekly, fortnightly, four-weekly, monthly, quarterly, six-monthly and annual amounts, and shows the annualised rent and daily rate. It saves time and prevents errors whenever you need to report a figure in a different period for accounting or mortgage purposes.

EPC improvements calculator

Lifting a property to a higher Energy Performance Certificate band can feel opaque. The EPC improvements calculator estimates upgrade costs, ranks low-cost measures by value and gives an example finance figure, producing comparable numbers for budgets, lender conversations and compliance planning.

Property inventory calculator

Knowing when to replace items across a property is hard to track. The property inventory calculator estimates lifespans and costs, builds a timed replacement plan and suggests a yearly reserve, which helps with budgeting and tenancy planning.

For more complex deals

HMO calculator

Houses in multiple occupation can deliver higher returns but are more complex to run. The HMO calculator projects cash flow, yields, interest cover, breakeven occupancy and refinance value in one place, giving a clear read on whether a property works as an HMO before you take it on.

How to get the most from the tools

The calculators are free, need no login and work on demand, so the best approach is to use them actively rather than once. Run more than one scenario, testing an optimistic and a cautious set of assumptions. Stress test a deal by adding an extra void month or nudging the interest rate up, and see what survives. Bookmark the ones you return to, and point other landlords toward them. Used this way they become a habit rather than a one-off check.

Frequently asked questions

Which calculator is most useful for landlords? 

It depends on where you are. If you are buying, the stamp duty and rental yield calculators come first; if you are running a property, the cash flow and pro-rata rent tools earn their keep; and for an HMO, the dedicated HMO calculator is the one to use.

Are the calculators up to date for 2026? 

Yes. The stamp duty tool reflects the current thresholds and surcharges across all four UK nations, and the mileage tool uses the 2026/27 rate of 55p for the first 10,000 business miles.

How accurate are the yield and cash flow tools? 

They are as accurate as the figures you put in, so include realistic estimates for voids, fees and maintenance, and run more than one scenario to test your assumptions.

Do I need to sign up to use them? 

No. Every calculator is free and available without an account or subscription, as often as you like.

Can tenants use them too? 

Some, yes. The pro-rata rent, rent affordability and weekly-to-monthly rent tools are useful on both sides of a tenancy, even though the suite is built with landlords in mind.

Final thoughts

Landlords make better decisions with clear numbers in front of them, and that is all these tools are for: fast, accurate answers on yield, cash flow, stamp duty, tax and tenant affordability, free and without a sign-up. You can try the full suite at augustapp.com/calculators, and if you would like the same clarity across your whole portfolio rather than one calculation at a time, you can start for free on August.