Naturalisation Calculator: When Can You Apply for British Citizenship?
Check the earliest date you can apply for British citizenship after ILR. The calculator applies the 12-month ILR rule, the 450-day and 90-day absence limits, the 3-year spouse route and the physical-presence anchor date.
You can usually apply for British citizenship by naturalisation 12 months after your Indefinite Leave to Remain was granted, provided you have lived in the UK for 5 years and stayed within the absence limits — no more than 450 days outside the UK in those 5 years and no more than 90 days in the final 12 months. If you are married to or in a civil partnership with a British citizen, there is no 12-month wait and the residence period is 3 years (270-day absence limit). The naturalisation fee in 2026 is £1,839.
When you can apply for citizenship after ILR
Naturalisation is the process of becoming a British citizen under the British Nationality Act 1981 using Form AN. On the standard route you must have held ILR, settled status or indefinite leave to enter for at least 12 months before the Home Office receives your application — so the earliest timing point is the first anniversary of your ILR grant. You must also have been lawfully resident in the UK for the 5-year qualifying period and meet the absence and good-character requirements. The calculator above checks the 12-month gate, your absences and the anchor date against the application date you enter.
Residence and absence limits by route
The two naturalisation routes use different residence periods and absence allowances. The table below summarises the limits this calculator applies.
| Requirement | Standard route | Spouse of a British citizen |
|---|---|---|
| Residence (qualifying) period | 5 years | 3 years |
| Must hold ILR / settled status | Yes — for 12 months | Yes — no 12-month wait |
| Total absence limit | 450 days | 270 days |
| Absence limit in final 12 months | 90 days | 90 days |
| Physical presence anchor date | 5 years before | 3 years before |
| Life in the UK test & English (B1) | Required (reusable from ILR) | Required (reusable from ILR) |
Source: GOV.UK — Apply for citizenship with ILR and Check if you can become a British citizen, under the British Nationality Act 1981. The Home Office retains discretion to overlook excess absences in some circumstances.
The physical-presence anchor date
This is the most commonly missed rule. You must have been physically in the UK on the day exactly 5 years (or 3 years on the spouse route) before the date the Home Office receives your application. If you were abroad on that exact day, your application can be refused — even if your total absences are within the limit. The fix is simple: move your submission date forward to a day on which you were present in the UK the required number of years earlier. The calculator flags this so you can adjust the date.
The 3-year spouse route
If you are married to or in a civil partnership with a British citizen, you can apply for naturalisation as soon as you hold ILR or settled status — there is no 12-month wait. The residence period is 3 years rather than 5, the total absence limit is 270 days rather than 450, and the 90-day final-year limit and the anchor-date rule both still apply. Switch the calculator to the spouse route to apply these figures. If you are still working towards settlement, start with our spouse visa ILR guide and the ILR eligibility calculator.
How much British citizenship costs
Citizenship is more expensive than many applicants expect, and unlike ILR there is no priority service to speed it up.
| Item | Cost | Notes |
|---|---|---|
| Naturalisation application (Form AN) | £1,709 | Per applicant; non-refundable if refused |
| Citizenship ceremony fee | £130 | Payable after approval |
| Total Home Office fee | £1,839 | Application + ceremony |
| Life in the UK test | £50 | Only if not already passed for ILR |
| English language test | ~£150 | Only if no qualifying qualification / exemption |
| Biometric enrolment | £0 | No fee |
Source: GOV.UK — Apply for citizenship: fees, June 2026. Always confirm the live fee on GOV.UK before applying.
Other naturalisation requirements
Meeting the residence and absence rules is necessary but not sufficient. You must also satisfy:
- Good character. The Home Office checks your criminal record, immigration history, and financial conduct (including unpaid tax or NI). Recent immigration breaches or unspent convictions can lead to refusal.
- Life in the UK test. Required, but if you passed it for ILR the result is valid indefinitely and does not need retaking.
- English language. CEFR B1 or above, or a qualifying degree or nationality exemption — again reusable from your ILR application.
- Two referees. Form AN requires two referees who meet the Home Office criteria.
Naturalisation: frequently asked questions
When can I apply for British citizenship after ILR?
What are the 450-day and 90-day absence rules for citizenship?
Can I apply for citizenship without waiting 12 months after ILR?
What is the physical presence (anchor date) rule for naturalisation?
How much does British citizenship cost in 2026?
Do I need to retake the Life in the UK test for citizenship?
Our editorial and accuracy standards
ILR Calculator UK is an independent, free settlement and citizenship planning resource. The rules, limits and fees on this page are taken directly from the British Nationality Act 1981, the published Home Office nationality guidance and GOV.UK, with the primary source linked at the point it is used. The calculator runs entirely in your browser and stores no data. We review the tool and content after each fees or guidance change and record the review date at the top of the page.
This site provides general information, not regulated immigration advice. For a binding assessment of your own case, contact an adviser regulated by the Immigration Advice Authority (IAA) or a solicitor listed on the Law Society’s Find a Solicitor register.