How do I complete the IHT400 form?
- 1The IHT400 is a 20-page inheritance tax return required when an estate exceeds £325,000 (or up to £500,000 if the residence nil-rate band applies), or when it does not qualify as an excepted estate.
- 2The form must be submitted to HMRC within 12 months of the end of the month in which the person died, and inheritance tax must be paid within six months of death or interest starts accruing.
- 3Most IHT400 submissions require supplementary schedules — commonly IHT405 (property), IHT406 (bank accounts), IHT407 (household goods), IHT419 (debts), and IHT435 (residence nil-rate band claim).
- 4All asset values must be recorded at the date of death, not current market values — incorrect valuations are one of the most common causes of HMRC queries and penalties.
- 5Professional help from a solicitor or probate specialist typically costs £1,500–£5,000 and is deductible from the estate; most executors use professional help given the complexity of the form.
IHT400 is 20-page Inheritance Tax form required if estate exceeds £325,000 (or £500,000 with RNRB). Include supplementary schedules for property, shares, trusts, gifts. Takes 6-20 hours; most use solicitors (£1,500-£5,000). Submit within 12 months. Need valuations, bank statements, 7-year gift records. HMRC reviews all IHT400s—inaccurate valuations incur penalties.
- When required: Estate over £325K (or £500K with RNRB), or complex estates
- Form size: 20 pages main form plus schedules (varies by assets)
- Time to complete: 6-20 hours (most use professional help £1,500-£5,000)
- Deadline: Within 12 months of death
- Documents needed: Valuations, bank statements, pension details, gift records
- Common errors: Incorrect valuations, missing schedules, gift calculation mistakes
IHT400 Key Facts
- • 20-page main form plus supplementary schedules
- • Required if estate exceeds £325K (or £500K with RNRB)
- • Takes 6-20 hours to complete
- • Must submit within 12 months of death
- • Most people use professional help due to complexity
IHT400 vs IHT205: Which Form Do You Need?
Before starting, understand your Inheritance Tax obligations for 2026-26. Use IHT400 (full form) if estate:
- Over £325,000 (or £500K with RNRB)
- OR includes foreign assets over £100K
- OR includes trust property
- OR deceased made large gifts in last 7 years
- OR doesn't qualify as "excepted estate"
Use IHT205 (simple form) if ALL apply:
- Estate under £325K (£500K with RNRB)
- UK domiciled
- No trust assets
- No gifts over £3K/year in last 7 years
- Foreign assets under £100K
Before You Start: Documents Needed
Gather these before beginning the form. For detailed guidance on property values, see our guide on valuing an estate for probate:
- Death certificate
- Will (if there is one)
- Property valuations
- Bank statements (date of death balances)
- Investment valuations
- Pension statements
- Life insurance policy details
- Vehicle valuations
- Mortgage/debt statements
- Details of gifts in last 7 years
Create a spreadsheet listing all assets and debts - this becomes your reference.
Completing IHT400: Section by Section
Pages 1-3: About the Deceased
Basic information:
- Full name, date of birth, date of death
- National Insurance number
- Last address
- Marital status
- Domicile (UK for most people)
- Occupation
Pages 4-5: Executor Details
- Your name and address
- Contact details (phone, email)
- Relationship to deceased
Pages 6-8: UK Assets
List ALL UK assets with values at date of death:
- Property (use box IHT405)
- Bank accounts (use box numbers carefully)
- Savings and investments
- Personal belongings
- Vehicles
Critical: Use date of death values, not current values.
Pages 9-10: Debts and Liabilities
- Mortgage balance
- Loans and credit cards
- Funeral expenses
- Outstanding bills
Pages 11-12: Gifts and Transfers
List gifts made in 7 years before death:
- Gifts over £3,000 per year
- Transfers to trusts
- Gifts with reservation of benefit
Pages 13-15: Exemptions and Reliefs
- Spouse exemption (unlimited)
- Residence Nil-Rate Band (up to £175K) - see our RNRB guide for eligibility
- Business/agricultural relief
- Charitable gifts
Pages 16-18: Tax Calculation
Calculate tax:
- Total assets minus debts = Net estate
- Minus exemptions (spouse, charity)
- Minus Nil Rate Band (£325K + RNRB)
- = Taxable amount × 40% = Tax due
Pages 19-20: Declaration and Schedules
- List which schedules you're including
- Sign declaration (executor signature required)
IHT400 Schedules: Which Ones Do You Need?
| Schedule | When Needed |
|---|
| IHT405 | UK property (always if any property) |
| IHT406 | Bank accounts, savings |
| IHT407 | Household goods, vehicles |
| IHT411 | Listed shares, unit trusts |
| IHT419 | Debts owed by deceased |
| IHT403 | Gifts in last 7 years |
| IHT435 | Residence Nil-Rate Band claim |
| IHT436 | Transferring RNRB from late spouse |
Most common: IHT400 + IHT405 + IHT406 + IHT407 + IHT419 + IHT435
Common IHT400 Mistakes to Avoid
Top Mistakes
- • Wrong asset values - use professional property valuations
- • Missing assets - forgotten accounts, Premium Bonds
- • Using current values not date of death values
- • Not including joint property share
- • Forgetting gifts in last 7 years
- • Arithmetic errors - check calculations twice
- • Missing schedules - form rejected if incomplete
- • Not claiming all reliefs (RNRB, spouse exemption)
Submitting IHT400 to HMRC
Submission Methods
Online (recommended):
- Via HMRC Inheritance Tax online service
- Faster processing (1-3 weeks typically)
- Can track progress
- Still need to post supporting documents
Paper:
- Post to: HMRC Inheritance Tax, BX9 1HT
- Slower (3-6 weeks)
- No tracking
- Use recorded delivery
Include With Submission
- Completed IHT400 and schedules
- Copy of will
- Copy of death certificate
- Property valuations
- Bank letters confirming balances
- Investment valuations
- Evidence of debts
HMRC Processing and Queries
Typical timeline:
- Simple estates: 2-4 weeks
- Complex estates or queries: 6-12 weeks
HMRC may query:
- Property valuation seems low
- Missing gift information
- Unclear beneficiary shares
- Need additional evidence for reliefs
Response time: Usually 30 days - respond quickly to avoid delays
Paying Inheritance Tax
When it's due: 6 months after end of month of death
Must be paid BEFORE probate grant issued
Payment methods:
- Direct Payment Scheme from deceased's accounts
- Pay from own funds (reclaim from estate later)
- Installments for property (10 annual payments, interest charged)
After HMRC Clearance
Once HMRC is satisfied:
- Issues IHT reference number
- Confirms tax position
- Provides clearance to apply for probate
Use IHT400 with probate application - registry won't process without IHT clearance. Next step: apply for probate.
Getting Professional Help
Consider professional help if:
- Estate over £500K
- Business assets
- Foreign property/assets
- Complex gifts
- Unsure about any section
Typical costs: £1,500-5,000 (deductible from estate)
IHT400 Summary
- ✓ Required for estates over £325K (or £500K with RNRB)
- ✓ 20-page form plus schedules
- ✓ Must submit within 12 months
- ✓ Takes 6-20 hours to complete
- ✓ Submit online for faster processing
- ✓ Keep records for 20 years
- ✓ Professional fees (£1,500-5,000) deductible