IHT400 Calculator UK: Estimate Inheritance Tax in Minutes

Q: Who needs to fill in form IHT400?

You typically need IHT400 if the deceased's estate is worth more than the Inheritance Tax threshold (£325,000), or if the estate includes certain assets like trusts or foreign property, even if no tax is due. It is the main account used by HMRC to calculate the exact tax liability.

Q: What is the 7-year rule for gifts?

Gifts made more than 7 years before death are generally exempt. Gifts made within 7 years are Potentially Exempt Transfers (PETs). If the total gifts plus the estate exceed the NRB, tax may be due on the gifts. Taper relief applies to gifts made between 3 and 7 years.

Q: How accurate is this calculator?

This tool provides an estimate based on standard UK tax rates (2024/2025) and simplified rules for things like taper relief and the 36% reduced rate. Complex situations involving Business Relief, Agricultural Relief, or foreign assets may require professional advice. This tool runs locally in your browser and does not submit data to HMRC.

Q: When must IHT be paid?

IHT is generally due by the end of the 6th month after the date of death. Interest is charged on late payments. You can pay IHT in instalments over 10 years for certain assets like property, but the first instalment is still due by the 6-month deadline.

Estimate the Inheritance Tax (IHT) due on an estate and see a breakdown relevant to the HMRC IHT400 form. This tool uses current UK tax thresholds (2024/2025) to calculate the gross estate, available allowances, and potential tax liability.

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1. Assets

Main Residence

Other Property

Cash & Savings

Investments

Possessions

Advanced Assets (Business, etc.)

Business / Agricultural assets

Other assets

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2. Liabilities & Debts

Mortgages

Loans & Cards

Funeral Expenses

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3. Exemptions

To Spouse / Partner (Tax-Free)

To Charity (Tax-Free)

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4. Allowances

Transferable Nil-Rate Band

Residence passed to direct descendants?

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5. Gifts (Last 7 Years)

Total Gifts Given

Split by Year (Advanced Taper)

0 to 3 years ago

3 to 4 years ago

4 to 5 years ago

5 to 6 years ago

6 to 7 years ago

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6. Dates

Date of Death

Calculation Summary

Rough Estimate

Gross Estate £0

Less Liabilities - £0

                        Net Estate
                        £0
                    

Less Exemptions - £0

Chargeable Estate £0

NRB Used Taxable

NRB: £325,000 RNRB: £0

Est. IHT Due

£0

@40%

IHT400 Ready Notes

Chargeable Estate: £0
Assets: Use Schedule IHT405 (Property) & IHT404 (Goods).
Gifts: Complete Schedule IHT403 if applicable.
Reduced Rate: Requires Schedule IHT430 if claiming 36%.

How this IHT calculator works

Gross Estate: We sum all assets (property, cash, investments, etc.) declared in the IHT400 schedules.
Net Estate: We deduct allowable liabilities (mortgages, debts, funeral expenses) specific to the estate.
Exemptions: We subtract amounts left to a spouse/civil partner or UK charities, as these are typically tax-free.
Nil-Rate Band (NRB): The standard £325,000 threshold is tax-free. Any unused percentage from a predeceased spouse can be added (Transferable NRB).
Residence Nil-Rate Band (RNRB): An additional allowance (up to £175,000) if a residence is passed to direct descendants, tapered if the estate is over £2m.
Gifts: We calculate gifts in the last 7 years. These eat into the NRB first. If gifts exceed the NRB, taper relief may reduce the tax owed depending on how long ago the gift was made.

Key Terms Explained

Nil-Rate Band (NRB)

The tax-free threshold for Inheritance Tax. Currently £325,000. Anything above this in the taxable estate is usually taxed at 40%.

Residence Nil-Rate Band (RNRB)

An extra tax-free allowance (up to £175,000) when a home is left to direct descendants (children, grandchildren). It tapers away for estates worth over £2 million.

Taper Relief

If a gift was made 3 to 7 years before death and exceeds the NRB, the tax due on that gift is reduced (tapered) the longer ago it was given.

Reduced Rate (36%)

If 10% or more of the net estate is left to charity, the IHT rate on the rest of the estate may drop from 40% to 36%.

Frequently Asked Questions

Who needs to fill in form IHT400? ▼

What is the 7-year rule for gifts? ▼

How accurate is this calculator? ▼

When must IHT be paid? ▼

🏠 1. Assets

💳 2. Liabilities & Debts

🤝 3. Exemptions

📊 4. Allowances

🎁 5. Gifts (Last 7 Years)

📅 6. Dates