UK Home and Bills Calculators: Mortgage Affordability, Overpayment, Energy Bills and Inheritance Tax
Free UK calculators for mortgage affordability, mortgage overpayments, energy bills, gas m3 to kWh, late payment interest and inheritance tax.
Buying a home and paying for it involves a lot of sums. These free UK calculators cover how much you can borrow, what overpaying saves, your energy bill and inheritance tax. They run in your browser and keep your figures private.
Use the results as a guide. Lenders, suppliers and HMRC set the final numbers.
Quick answer
| Question | Tool |
|---|---|
| How much could I borrow? | Mortgage Affordability Calculator |
| What does overpaying save? | Mortgage Overpayment Calculator |
| What is my yearly energy bill? | UK Energy Bill Calculator |
| How many kWh is my gas reading? | Gas m³ to kWh Converter |
| What interest can I charge on a late invoice? | Late Payment Interest Calculator |
| Will my estate owe inheritance tax? | Inheritance Tax Calculator |
Mortgage affordability
Lenders typically offer 4 to 4.5 times income, and up to 5.5 times for strong applications. Enter both incomes, your deposit, the rate and the term to see the maximum loan, the home price and the monthly payment. Test the payment at a rate two or three points higher to see if you could cope.
Overpayments
An extra amount each month goes straight onto the balance and cuts all later interest. On a £250,000 balance at 5 percent over 25 years, £200 extra a month saves around £41,000 of interest and shortens the loan by about 4 years. Check your deal for an overpayment limit, often 10 percent a year on fixed rates.
Energy bills
Enter your yearly kWh, the unit rate in pence and the standing charge. The calculator gives the yearly and monthly bill. If your meter shows cubic metres, the gas converter changes the reading to kWh using the volume correction factor and your calorific value.
Late payment interest
A business can claim 8 percent over the Bank of England base rate on a late invoice, plus a fixed fee of £40, £70 or £100.
Inheritance tax
Everyone has a £325,000 nil-rate band, plus up to £175,000 for a home left to children or grandchildren, and a spouse's unused allowance can be added. The rest is taxed at 40 percent. The calculator shows the tax and the effective rate.
Tips
- Add stamp duty, legal fees, surveys and moving costs to your home budget.
- Use a smart meter reading for the best bill estimate.
- Take advice for an estate near the allowance or with trusts and business assets.
Frequently asked questions
Is the data saved? No, everything is calculated in your browser.
Are tax rates current? They are the 2026-27 figures and can change.
