How do I claim tax relief for phone and internet costs?

If you use your phone or internet for work, you may be entitled to claim tax relief on part of those costs. Whether you are self employed or an employee who works from home, HMRC allows you to reclaim tax on the business-related portion of your phone and broadband expenses.

The key is understanding what qualifies as a business expense and how to calculate and claim it correctly. This article explains how to claim tax relief for phone and internet costs based on your working status and use.

Claiming phone and internet costs as a self employed person

If you are self employed, you can include the business portion of your phone and internet bills as an allowable expense on your Self Assessment tax return.

You can only claim for the part that relates to business use, not personal use. HMRC requires that the expense is wholly and exclusively for your business.

Mobile phone costs

If you use your mobile phone for both business and personal calls, you must work out a fair percentage of business use. For example:

• If half of your calls are work-related, you can claim 50% of your phone bill as an expense.

• If you have a separate mobile phone contract used only for business, you can claim the full cost.

Make sure you keep itemised bills or digital records to support your calculation.

Internet and broadband costs

Similarly, if you use your home internet connection for both business and personal purposes, you can only claim a proportion for business use.

For example:

• If you work from home two days a week, you might claim 2/7ths of your internet costs.

• If your internet is used almost entirely for business (such as uploading documents, video calls, or managing online client portals), you can justify a higher proportion.

If you pay for a dedicated business broadband line separate from your personal one, you can claim the full amount.

Example calculation

If your monthly internet bill is £40 and you use it 60% for business, you can claim £24 per month (£40 x 60%), or £288 per year as an expense.

This amount reduces your taxable profit, lowering the Income Tax and National Insurance you owe.

Claiming phone and internet costs as an employee

If you are employed but use your own phone or internet for work, you can also claim tax relief for business use—though the rules are stricter than for the self employed.

You can claim only if:

• The expenses are necessary for your job and not reimbursed by your employer.

• The use is wholly and exclusively for work.

This means occasional work calls or checking emails on your personal phone are unlikely to qualify.

What you can claim

You can claim tax relief on:

• Work-related calls made on your personal phone that you have paid for.

• A portion of your broadband bill if you work from home regularly and your employer requires it.

If your employer provides you with a work phone or pays part of your bill, you cannot claim additional relief on those costs.

Flat-rate tax relief for home working

If you work from home because your employer requires it, HMRC allows you to claim a flat-rate tax relief to cover additional household costs, including internet use.

As of 2025, the standard home working allowance is £6 per week (£312 per year). You can claim this without needing to provide receipts or calculate actual costs.

To qualify, you must work from home regularly and not just occasionally. If your employer already reimburses this amount, you cannot claim it again.

How to claim tax relief

For self employed people

You claim phone and internet costs through your annual Self Assessment tax return:

1. Record the business portion of your bills as allowable expenses.

2. Keep records, such as invoices and usage logs, to support your claim.

3. Enter the total on the “Expenses” section of your tax return under “Phone, fax, stationery, and other office costs.”

If you use accounting software such as Xero, QuickBooks, or FreeAgent, you can upload receipts and automatically track recurring monthly expenses.

For employees

You can claim tax relief in one of three ways:

1. Online via your Personal Tax Account on GOV.UK.

2. By completing form P87 if claiming for the current or previous four tax years.

3. Through your Self Assessment return if you already file one.

HMRC will either adjust your tax code to reflect the relief or issue a refund directly.

How much tax you can save

The amount of tax you save depends on your income tax rate and the value of your claim. For example:

• A basic rate taxpayer (20%) claiming £300 in expenses will save £60 in tax.

• A higher rate taxpayer (40%) claiming the same amount will save £120.

While these may seem like small amounts, they can add up over time, especially for those who work remotely or rely heavily on digital communication.

Evidence and record keeping

HMRC may ask for evidence of your claims, especially for proportional business use. Keep:

• Copies of phone and broadband bills.

• Notes of how you calculated business use (such as call logs or time spent online for work).

• Invoices for any separate business lines or mobile contracts.

Records must be kept for at least five years after the 31 January filing deadline for the relevant tax year.

Common mistakes to avoid

• Claiming for personal use: Only the business-related percentage is allowable.

• Double claiming: If your employer reimburses the cost, you cannot claim tax relief again.

• Overestimating usage: Always use reasonable and consistent calculations to avoid HMRC challenges.

How accountants can help

An accountant can help you:

• Work out the correct proportion of business use.

• Ensure your claims comply with HMRC rules.

• Include the correct expenses in your Self Assessment return.

• Avoid overclaiming or missing eligible deductions.

Professional guidance is especially useful if you run a home-based business or work part-time for yourself and an employer.

The bottom line

You can claim tax relief on phone and internet costs if they are used for business purposes. Self employed individuals can claim a reasonable portion of their bills through their Self Assessment return, while employees can claim specific relief for work-related use or a flat-rate home working allowance.

The key is to be fair, consistent, and well-documented. With accurate records and the right calculations, you can reduce your tax bill legitimately and ensure you are not paying more than you should.