## Use the rules already in force
The current [GOV.UK landlord overview](https://www.gov.uk/guidance/renters-rights-act-an-overview-for-landlords) says the Renters' Rights Act changes came into effect in England on 1 May 2026.
Existing assured shorthold tenancies changed to assured periodic tenancies, and new tenancies are assured periodic. The guidance says these tenancies run on a rolling basis and cannot have an end date in the tenancy agreement.
The overview also says a landlord cannot ask for, encourage or accept rent before the tenancy agreement is signed. It prohibits discrimination against prospective tenants who have children or receive benefits.
A tenant or prospective tenant can ask to keep a pet, and the overview says refusal requires a valid reason.
Most landlords or agents with existing written tenancies had to give each named tenant the official Information Sheet by 31 May 2026. The [Information Sheet guidance](https://www.gov.uk/government/publications/the-renters-rights-act-information-sheet-2026) says the existing written agreement did not have to be reissued solely for that change.
## Replace the old rent assumption
GOV.UK says a landlord increasing rent must use Form 4A and give the tenant at least two months' notice. A model that assumes an immediate or informal increase therefore does not match the published process.
Keep current annual rent as the base case. Put a proposed increase in a separate dated scenario rather than using it in the first month of the forecast.
The [gross and net yield calculator](/tools/gross-net-yield-calculator) separates annual rent from management, maintenance, insurance, void and other operating costs. It calculates net rent before borrowing and does not model lender stress, finance, tax or after-tax cash flow.
## Replace the section 21 exit assumption
The GOV.UK overview says section 21 no-fault eviction is no longer available for these tenancies. A landlord must use an applicable possession ground and the correct process.
The overview also says that where rent arrears are below three months, a court may decide the tenant can stay; where the tenant owes three months' rent, the court must make a possession order if the other requirements are met.
Those statements are legal-process inputs, not a forecast of the result or timing of an individual case.
## Rebuild the evidence row
Create one dated row for tenancy type, written terms, Information Sheet evidence, current rent, proposed Form 4A date, notice period and any possession ground being modelled. Keep professional legal advice outside the financial calculator.
The [due diligence checklist](/tools/due-diligence-checklist) covers tenancy, legal prompts and document records. Its controlled workflow pauses a deal until both red checks clear and converts amber checks into conditions or price adjustments.