Remortgage Calculator UK: Rates & Repayment Charges | Calclens
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Remortgaging or moving, costed in order

When a fixed rate ends or you outgrow your home, a chain of costs decides your next move. This guide runs the six calculations that matter — from the remortgage saving to early repayment charges and a fresh affordability check.

Your fix ends in three months. Stay, switch, or move?

SVR jump

when a fix ends

ERC

penalty to leave early

Re-check

affordability first

When a mortgage deal expires you don’t just “roll over” — you choose between the lender’s pricey standard variable rate, a new fix, overpaying, or moving altogether, and each has its own cost. Leave a deal early and an early repayment charge can wipe out the saving. Each calculator below settles one piece — run them in order to find the cheapest next step.

The remortgage & moving path, step by step

Six calculations in the order the decision unfolds — work out the saving first, check what leaving costs, then look at moving if that’s on the table.

The core saving

What would remortgaging save you?

When your fixed or tracker rate ends you usually drop onto the lender’s standard variable rate, which is typically much higher. Remortgaging to a new deal can save meaningfully each month. Work out the saving against your current and SVR rates before doing anything else.

Remortgage Calculator
The cost of leaving

Is there an early repayment charge?

Switch before your current deal ends and you may face an early repayment charge — often 1–5% of the balance, which can be thousands. Sometimes it still pays to switch early; often it’s better to wait. Check the ERC before you commit, because it can erase the remortgage saving entirely.

Early Repayment Charge Calculator
An alternative move

Would overpaying serve you better?

If your rate is already competitive, overpaying rather than remortgaging can cut your term and total interest — most lenders allow up to 10% a year penalty-free. Compare what an overpayment does against switching deals; sometimes the simplest move is the best one.

Overpayment Calculator
If you’re moving

Can you still borrow what you need?

Moving home means a fresh affordability assessment — rates, rules and your circumstances may have changed since you last borrowed. Check what a lender will offer now before you start viewing, so you’re searching in a realistic price range.

Affordability Calculator
The moving tax

What stamp duty will the new home cost?

A new purchase brings a fresh stamp duty bill, due in cash at completion on top of your deposit and fees. On a larger home it can be substantial. Work it out early so it doesn’t derail the move between offer and completion.

Stamp Duty Calculator
If the timing clashes

Do you need a bridging loan?

If you’re buying before your current home sells, a bridging loan can cover the gap — fast but expensive, with higher rates and fees. It’s a short-term tool, not a long-term plan. Understand the cost before relying on it to keep a chain together.

Bridging Loan Calculator

Why the order matters

The remortgage saving comes first because it’s the number every other decision is judged against — there’s no point weighing an early repayment charge or an overpayment until you know how much switching would actually save.

The early repayment charge comes straight after for a reason: it’s the single most common thing that turns a worthwhile remortgage into a bad one. A £3,000 ERC can swallow a year’s saving, so it has to be checked before you act, not discovered after. The moving steps only matter if relocating is genuinely on the table — settle the stay-or-switch question first.

Stay, switch, overpay or move — at a glance

When a deal ends you have four broad options. The right one depends on your rate, your plans and any early repayment charge.

Your situationLikely best move
Fix ending, better deals availableRemortgage to a new deal
Mid-deal, large ERC, good rateWait, then remortgage at maturity
Competitive rate, spare cashOverpay within the penalty-free limit
Outgrown the homeRe-check affordability, then move

These are starting points, not rules — a large enough saving can justify paying an ERC, and a move changes everything. The key is to cost each option before committing, beginning with the remortgage saving and the early repayment charge. Start with the remortgage calculator.

Start here

Ready to run your own numbers?

Begin with the remortgage saving — the figure every other option is judged against — then work down the path one calculator at a time.

Remortgage Calculator

A remortgage decision, worked through

One realistic example, run through the whole sequence, to show how the steps connect in practice.

Worked example Sara · fix ending in 4 months · £180,000 balance
  1. Remortgage saving. Her fix is ending and she’d roll onto the lender’s SVR, so switching to a new deal saves a meaningful amount each month.
  2. Early repayment charge. She’s near maturity, so the ERC is minimal — switching now versus waiting 4 months barely differs, and a new offer can be locked in advance.
  3. Overpay alternative. Her new rate is competitive, so she also models overpaying — but decides to remortgage first, then overpay within the penalty-free limit.
  4. Affordability. She’s staying put, not moving, so no fresh affordability check is needed this time.
  5. No move. With no purchase, stamp duty and bridging don’t apply — she stops at the remortgage, the cheapest next step.

The takeaway: the early repayment charge is what usually turns a good remortgage into a bad one. Sara checked it second — right after the saving — and because she was near maturity, switching made clear sense rather than being eaten by a penalty.

Five mistakes people make remortgaging or moving

The errors that recur among UK remortgagers and movers — and the ones that cost the most.

1

Drifting onto the standard variable rate

When a deal ends you roll onto the lender’s SVR, usually far higher. Doing nothing can cost hundreds a month. Line up a new deal 3–6 months before your fix ends.

Cost: hundreds a month on SVR Fix: remortgage before the fix ends
2

Switching mid-deal without checking the ERC

Leaving early can trigger an early repayment charge of 1–5% — thousands of pounds that can wipe out the saving. Always check the ERC before switching mid-deal.

Cost: a saving cancelled by penalty Fix: check the ERC first
3

Remortgaging when overpaying would do

If your rate is already competitive, overpaying can cut term and interest without the cost of switching. Compare overpaying against remortgaging rather than assuming a switch is best.

Cost: needless switching costs Fix: compare overpay vs remortgage
4

Underestimating stamp duty when moving

A new purchase brings a fresh stamp duty bill, due in cash at completion. On a larger home it’s substantial — and the additional-property rate can apply temporarily if you haven’t sold first.

Cost: a completion cash shortfall Fix: cost stamp duty before offering
5

Relying on a bridging loan as a default

Bridging finance is fast but expensive — high rates and fees — and meant for short gaps only. Treating it as a routine plan rather than a last resort can be costly.

Cost: high interest and fees Fix: use bridging only as a last resort

Remortgage and moving questions, answered

When should I start looking to remortgage?
Usually about three to six months before your current deal ends. Most mortgage offers are valid for up to six months, so you can lock in a new rate in advance and switch the moment your deal expires — avoiding even a single month on the lender’s higher standard variable rate. Leaving it until the deal ends risks an expensive gap.
What is an early repayment charge?
An early repayment charge (ERC) is a fee for leaving your mortgage deal before it ends — commonly 1–5% of the outstanding balance, often tapering down as the deal nears its end. On a large balance that can run to thousands of pounds. Always check the ERC before remortgaging mid-deal, as it can outweigh any saving from switching.
Is it better to remortgage or overpay?
It depends on your current rate. If you’re on a competitive deal, overpaying (usually up to 10% a year penalty-free) cuts your term and total interest without the cost of switching. If your rate is uncompetitive or about to jump to the SVR, remortgaging to a better deal usually wins. Compare both before deciding.
Do I pay stamp duty when I move home?
Yes — buying a new main home triggers a fresh stamp duty bill on the purchase, payable in cash at completion. The amount depends on the price and is separate from your deposit and fees. If you haven’t sold your old home before completing on the new one, the higher additional-property rates can temporarily apply, with a refund available later in some cases.
What is a bridging loan and when would I need one?
A bridging loan is short-term finance to cover the gap when you buy a new home before selling your current one. It’s fast but expensive — higher interest and fees — and meant to be repaid quickly, usually once your old home sells. It can keep a chain together, but the cost means it’s a last resort rather than a default plan.
Will my affordability be reassessed when I move?
Yes. Moving home means a new mortgage application and a fresh affordability assessment, which considers your income, outgoings, debts and current interest rates — all of which may have changed since you last borrowed. Check what you can borrow now before you start viewing, so you’re looking in a realistic range rather than being surprised later.
Can I remortgage to release equity?
Often yes — if your home has risen in value or you’ve paid down the balance, you may be able to remortgage for a larger amount and take the difference as cash. This increases your borrowing and monthly payments, so it’s worth modelling the new repayment carefully. Lenders will assess affordability for the higher amount before approving it.

How this guide is built

The sequence follows how a remortgage or move actually unfolds — work out the saving, check the cost of leaving, then assess moving if relevant — the order a mortgage broker would walk you through.

Every calculator linked here is a free Calclens tool with its own methodology and worked examples. Standard variable rates, early repayment charges, overpayment limits and stamp duty follow current lender practice and HMRC and GOV.UK guidance; the individual calculator pages carry the detail.

Definitions and sources: methodology · sources.

Not financial advice. This guide is for general information and links to calculators that produce estimates. Mortgage decisions depend on your circumstances and lender criteria — confirm figures with a qualified mortgage adviser before acting.

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