Stamp Duty (SDLT) and affordability for couples: the deposit trade‑off
SDLT is an upfront cost that can quietly reduce your deposit. A smaller deposit increases your loan, which increases monthly payments. This page shows how to treat SDLT as part of affordability decisions (not an afterthought).
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Worked examples
Each example uses the same calculator engine. Use “Open in calculator” to share or compare scenarios.
Standard buyer, typical UK costs, include an emergency buffer
Incomes: A £3,400 · B £2,400
Shared total: £2,820 / month
Split (proportional): A £1,653 · B £1,167 · Leftovers: A £1,747 · B £1,233
FAQ
If we pay SDLT from savings, does it affect our mortgage?
It can. If SDLT reduces the cash available for the deposit, your loan amount may increase — and that increases the monthly mortgage payment.
Do surcharges stack (additional property + non‑UK resident)?
Yes. The calculator’s SDLT module stacks these onto the residential bands when they apply, and surfaces notes for transitional rules.
Should we split SDLT 50/50?
Some couples do, others split proportional to savings or income. The key is clarity: agree how you fund upfront costs, then agree how you fund monthly costs.
Related links
Related guides
Mortgage & bills split calculator
Run your numbers live and share a scenario link.
50/50 vs proportional vs custom splits
Choose a split that feels fair and stays sustainable.
Split the mortgage by income (UK)
Proportional splits explained with worked examples.
Proportional bills split calculator guide
Turn take-home pay into a clean monthly split.
66/33 vs 50/50 split for couples
When a custom split beats proportional (and when it doesn’t).
Stamp Duty (SDLT) calculator for couples
Standard vs first-time buyer relief + surcharges.
60/40 bills split guide
A simple compromise between 50/50 and proportional.
70/30 bills split guide
When a fixed split makes sense (and how to validate it).
75/25 bills split guide
For very different incomes: keep leftovers and resilience in view.
Should we split the mortgage 50/50?
A simple decision framework using leftovers and stress tests.
Tip: open a guide in one tab and the calculator in another to compare options quickly.