Add up twelve months of your cell phone bill and twelve months of home internet, and most self-employed owners are staring at $2,000 to $4,000 a year. If you run your business from that phone and that connection — client calls, quotes, invoicing, email, video meetings, cloud software — a real slice of that money is an ordinary business expense, and the tax code lets you deduct it. The catch is the word slice: you can only deduct the business-use percentage, you have to be able to back it up, and the most common way owners handle this deduction is also the fastest way to lose it in an examination. Here is how to get it right.
The One Rule That Governs Both Deductions
Your cell phone and your home internet live under the same basic test as every other business expense: the cost must be ordinary and necessary for your trade or business. A phone you use to talk to clients and an internet connection you use to send invoices and run video calls both clear that bar easily.
But both are classic mixed-use expenses — part business, part personal — and mixed-use expenses must be allocated. If 60 percent of your phone use is business, you deduct 60 percent of the bill. The personal 40 percent is never deductible, no matter how you label it. Everything in this guide flows from that single idea: figure out the business percentage honestly, document how you got there, and deduct that amount.
Your Cell Phone: Deductible, but Almost Never 100%
Start with the good news about substantiation. Cell phones used to be "listed property," a category that carried painful heightened recordkeeping rules. Congress removed cell phones from that category in the Small Business Jobs Act of 2010 (the IRS followed up with Notice 2011-72), which means you no longer need the kind of contemporaneous mileage-log-style proof the old rules demanded. Standard business records — bills plus a reasonable basis for your percentage — are enough.
Now the warning that matters more: a single phone you carry everywhere is not a 100% business phone. The deduction is limited to the business-use slice, and a round 100% claim on a phone that also holds your family photos, personal texts, and social media apps is exactly the kind of entry that invites questions. There are only two clean paths to a full deduction:
- A second phone used exclusively for business. A dedicated business line with no personal use is fully deductible — service and device alike.
- An employer-style arrangement that doesn't apply to you. If an employer provides a phone primarily for business reasons, the value can be excluded from the employee's income as a working-condition fringe benefit. As the owner, your path is the Schedule C deduction described below, not this rule.
If you have one phone for everything, pick a defensible percentage and deduct that. A freelancer who takes client calls all day might land at 70 or 80 percent; a consultant whose phone is mostly personal with some business email might land at 30 percent. The number itself matters less than the fact that you can explain it.
One related trap: the first landline in your home is never deductible. The tax code specifically disallows basic local service on the first wired line to your residence, even if you use it heavily for business. Business long-distance charges on that line are deductible, and a second line installed for business is fully deductible — but the base charge for line number one stays personal.
Your Home Internet: The Same Allocation, Without the Exclusive-Use Test
Home internet follows the same allocate-and-deduct logic, with one important distinction from the home-office deduction: there is no exclusive-use requirement for the connection itself. The home-office rules demand that a room be used regularly and exclusively for business before a penny of rent or utilities flows through that form. Your internet bill carries no such test. You do not need a dedicated business-only connection to deduct the business share of the one you have.
That makes internet simpler than the office, but the allocation still has to be reasonable. Think about how the connection is actually used in your household: hours of video meetings and cloud work versus evening streaming and gaming, or the share of devices that exist for the business. A solo owner working full days from home will often support a higher percentage than someone who checks email from the couch after a day at a job site. Either way, write down the reasoning when you set the number — a one-sentence note made now beats a reconstructed memory two years from now.
If you claim the home-office deduction on Form 8829, keep the internet handling consistent: many owners deduct the business percentage of internet directly as a utility expense and leave it out of the home-office computation so the same dollars are never counted twice.
Three Ways to Set a Percentage You Can Defend
You do not need to meter every minute of every day. You need a method that is reasonable, applied consistently, and written down. Any of these works:
1. The representative-month sample
Pick one typical month per quarter. For that month, go through the itemized phone bill and mark business versus personal calls, or tally business data use against total use. Average the four samples into an annual percentage. Save the marked-up bills or a short summary of each sample. This is the strongest method because it is built from your carrier's own records.
2. The call-and-data log review
If your usage is steady month to month, do the exercise once for a representative month and re-check it once a year or whenever your business changes meaningfully — a new line of work, kids home for the summer shifting household streaming, a second line added. Note the review date in your records so the percentage never looks stale.
3. The time-based estimate, documented
If itemized logs are impractical (flat-rate unlimited plans with thin detail, for example), estimate from documented reality: business call hours from your calendar and call history, workdays versus total days, or the share of data consumed by business apps during a test week. "About 60% because most days" is a guess; "60% based on call-history review for March showing 58 of 96 outgoing calls were client-related, rounded" is a method. Write the one sentence that turns yours into the second kind.
Whichever method you choose, keep three things with your tax file each year: the annual bills (or year-end summary), the worksheet showing the percentage math, and the one-paragraph note describing the method. That folder is the entire difference between a deduction that survives questions and one that does not.
Don't Forget the Hardware
The monthly service is only half the deduction. The devices and gear that connect you count too:
- Handset, router, modem, booster, headset, chargers, cases. The business-use percentage applies to equipment just as it does to service.
- Small costs can usually be expensed outright. Most self-employed owners can use the de minimis safe harbor election (up to $2,500 per item for businesses without audited financial statements) to deduct the business portion of a phone or router in the year of purchase instead of depreciating it. You claim the election with a statement attached to a timely filed return — your tax software or preparer handles the mechanics.
- Pricier setups get depreciated. If equipment exceeds the safe harbor or you prefer, depreciate the business portion over its recovery period. Either way, personal-use percentage never sneaks back in through the equipment door.
Where the Deduction Goes on Your Return
For a sole proprietor or single-member LLC filing Schedule C, phone and internet service generally land on line 25 (Utilities) at the business-use amount — so a $1,800 annual phone bill at 60% business use becomes a $1,080 entry. Equipment you expense under the safe harbor typically goes to line 27a (Other expenses) as "de minimis safe harbor" or to the depreciation lines if you depreciate; follow your software's prompts or your preparer's lead. Partnerships, S corporations, and C corporations report the same kinds of costs on their own returns, and owners employed by their own corporation generally need an accountable-plan reimbursement rather than a personal deduction — worth a conversation with your preparer before you assume.
Two boundary notes so nothing here misleads you. First, W-2 employees: Congress suspended the deduction for unreimbursed employee expenses starting in 2018, so if your only income is a paycheck, you generally cannot deduct phone and internet costs yourself — this guide is written for self-employed owners, and employees should seek reimbursement from the employer instead. Second, reimbursements cut both ways: any portion your business already reimbursed to you tax-free cannot also be deducted. Deduct only what actually came out of your pocket.
Five Mistakes That Cost Owners This Deduction
Claiming 100% on a mixed-use phone. The single most common error, and the hardest to defend. Unless the device is genuinely business-exclusive, take a percentage.
Deducting the first home landline. Basic local service on line one is nondeductible by statute. Deduct the business toll calls and any second business line instead.
Keeping no records at all. The relaxed substantiation rules removed the old listed-property regime; they did not remove the need for proof. Bills plus a percentage worksheet plus a method note is the whole job — skipping it turns a legitimate deduction into an unprovable one.
Letting the bill live in someone else's name with no paper trail. A phone on a spouse's family plan or internet billed to a partner can still support your deduction for the share you actually pay — but only if you can prove payment and business use. Keep bank or card statements showing you paid, alongside the usage records.
Setting a percentage once and freezing it forever. A 70% allocation from the year you prospected by phone all day may be fiction in the year you hired a salesperson and barely call anyone. Revisit the number annually; a stale percentage that no longer matches your life undermines the credible years too.
A 30-Minute Annual Routine
Put this on the calendar each January and the deduction mostly takes care of itself: download the year's bills into one folder, run one representative-month sample (or confirm last year's still fits), update the percentage worksheet, note any equipment bought or retired, and file the packet with the return. Thirty minutes, once a year, protects a deduction worth hundreds of dollars — and it is exactly the kind of small discipline that compounds across every line of your return.
Simplify Your Financial Management
Getting allocations like phone and internet right is easier when every bill already lives in one searchable ledger instead of scattered across inboxes and carrier portals. Beancount.io gives you plain-text accounting that is transparent, version-controlled, and AI-ready, so a business-use worksheet is never more than a query away. Get started for free and keep deductions like this one documented from day one.
