Hobby Income vs. Business Income: What Changes When the IRS Draws the Line

The Bottom Line

If you’ve made money from something you do on the side — and you’re not sure whether the IRS considers it a hobby or a business — that question has a real dollar answer. The classification changes two things: whether expenses can be deducted against the income, and whether self-employment tax applies. On the same revenue, those two rules can produce very different tax bills.

The Two Tax Paths

The difference between hobby and business classification comes down to one question: can expenses be deducted against the income?

Under hobby classification, the full revenue is taxable — expenses don’t come off. Under business classification, only the profit is taxable, but self-employment tax applies on top. The same revenue can produce two very different tax bills depending on which column applies:

The expense rule is worth slowing down on, because it’s one of the more counterintuitive parts of the tax code. Before the Tax Cuts and Jobs Act, hobby expenses could reduce hobby income — up to the amount of that income. That changed. Under current TCJA rules, hobby expenses don’t come off at all. Someone with $5,000 in hobby revenue and $4,000 in costs still owes income tax on the full $5,000.

What the Gap Looks Like in Practice

The abstract version of this rule is easy to nod along to. The dollar version is where it lands. Here’s what the same activity looks like under each classification:

Example — Marcus’s Prints and Metalwork

Marcus designs and sells hand-cut art prints and small metalwork pieces at local markets and through his own website. He’s been at it for two years. His numbers for the year:

• Gross revenue: $6,500
• Expenses (materials, market table fees, packaging, shipping): $4,200
• Net: $2,300

Whether the IRS classifies Marcus’s activity as a hobby or a business determines which row of this table describes his situation:

	Hobby Classification	Business Classification
Taxable amount	$6,500 (gross revenue)	$2,300 (net profit)
SE tax	$0	~$325
Income tax (~22% bracket)	~$1,430	~$470
Estimated total	~$1,430	~$795

The business totals do not reflect the half-of-SE-tax above-the-line deduction (~$163), which would reduce the income tax slightly — bringing the estimated business total closer to ~$759. See Hobby Income and Self-Employment Tax.

Under hobby classification, Marcus owes roughly $635 more in tax on the same $6,500 of revenue — because the $4,200 he spent on the activity cannot be deducted.

These figures are estimated at the 22% bracket on net taxable income. Actual amounts depend on Marcus’s full income, filing status, applicable deductions, and state rules.

The estimator runs this comparison for any revenue and expense level — see where your activity falls →

For the deduction mechanics in detail: Hobby Tax Write-Offs: What Is and Isn’t Deductible.

How the IRS Decides: The 9-Factor Test

Here’s where it gets more nuanced. There’s no box on a tax form where a filer declares “this is a hobby” or “this is a business.” The IRS makes that determination itself, using a 9-factor test defined in Treasury Regulation §1.183-2(b). No single factor controls the outcome — the IRS weighs the full picture, and reasonable people can look at the same situation and read it differently.

The nine factors ask, in plain terms:

1. Does the activity run more like a business or a pastime? — Are there dedicated books, separate accounts, and recordkeeping that reflect for-profit management?
2. Has the person prepared to make it profitable? — Studying the market, consulting experts, adjusting the approach based on results.
3. Is the time invested consistent with wanting to earn a profit? — Time alone doesn’t decide it; a person can spend considerable time on a pastime. The question is whether the pattern of effort signals commercial intent.
4. Could the activity’s assets appreciate enough to create a payoff later? — More applicable to land, livestock, and capital-intensive activities where the investment itself may appreciate even if annual income is low.
5. Has the person converted similar activities into profitable ventures before? — A track record of turning passion projects into commercial ones supports profit intent.
6. What does the profit-and-loss pattern show over time? — A string of losses isn’t automatically disqualifying, but the trend matters. An activity that is structurally unprofitable invites scrutiny regardless of intent.
7. When profits occurred, how large were they relative to the investment? — One substantial profitable year in a run of losses can still support profit intent if the profit is large enough relative to losses.
8. Is this income financially important to the person, or incidental to substantial other income? — Activities that don’t meaningfully contribute to the livelihood of a high-income filer draw more scrutiny.
9. Would the person do this activity regardless of whether it produced income? — Activities that are recreational by nature — photography, art, writing, woodworking, crafts — face more scrutiny under this factor. Personal enjoyment doesn’t disqualify an activity, but it raises the bar.

Knowledge Check — The 9-Factor Test

Question 1: A hobby earner with $4,000 in revenue and $3,000 in expenses owes income tax on how much under current TCJA rules?

• A) $1,000 — the net amount after expenses
• B) $4,000 — the gross revenue, because hobby expenses are not deductible
• C) $0 — hobby income under $5,000 is not taxable

Question 2: Which of the following is NOT one of the IRS’s 9 factors for determining hobby vs. business classification under Treasury Reg. §1.183-2?

• A) The profit history over time — whether the activity has shown income or losses
• B) Whether a 1099-K or 1099-NEC was received for the income
• C) The manner in which the activity is carried on — whether it runs like a business or a pastime

The Safe Harbor: When Profit History Settles the Question

There’s one situation where the hobby-vs-business question gets a clean, mechanical answer — no judgment calls, no weighing of factors. A Safe Harbor under IRC §183(d) kicks in when an activity shows a net profit in at least 3 of the last 5 consecutive tax years. Clear that bar and the IRS presumes the activity is a business. That shifts the burden of proof to the government if it wants to challenge that conclusion.

Outside the Safe Harbor, the full 9-factor test applies — and the outcome depends on how the activity is run, documented, and conducted over time.

Which path applies?

Horse breeding, training, and racing activity follows a different Safe Harbor: profit in 2 of 7 consecutive years under a specific provision of §183(d).

For a full walkthrough of the Safe Harbor and the audit risk outside it: The Hobby Loss Rule Explained.

What Doesn’t Change the Classification

A few things that seem like they’d settle the hobby-vs-business question actually don’t — at least not on their own:

• Having an LLC — entity formation is one piece of evidence that the activity is run in a businesslike manner. It’s a factor, not a determinant.
• Filing Schedule C in prior years — how a return was filed in the past is noted but does not bind the IRS’s current assessment.
• Receiving a 1099 — a 1099-K or 1099-NEC documents what was paid. It does not establish §183 status in either direction.
• Spending a lot of time on the activity — time devoted is one of the 9 factors. Significant time on a structurally unprofitable activity doesn’t resolve the classification on its own.

When Classification Gets Challenged

Most hobby earners are never audited on classification. But the IRS tends to look more closely at an activity when several things are true at once:

• Losses repeat year after year with no visible path toward profitability
• The activity has a strong recreational or personal enjoyment element
• The filer has substantial income from other sources, making the activity financially incidental
• There are no records, separate accounts, or documentation that suggest the activity is run for profit

Photography, horse operations, art, farming, and online content creation come up more frequently in §183 Tax Court disputes than other activities — because they sit squarely in the overlap between passion and commerce, which puts them in the contested zone of the 9-factor test. That’s not a warning. It’s just where the gray area tends to collect.

One More Detail: Retroactive Reclassification

When the IRS reclassifies an activity from business to hobby status, the reclassification typically applies to prior open tax years — not just the current one. That can mean additional income tax, SE tax that was previously deducted, interest, and accuracy penalties reaching back up to three years (longer if substantial understatement of income is involved). An activity consistently filed on Schedule C that the IRS later reclassifies doesn’t just affect the current return — it reopens prior years as well. For filers whose activities sit in the gray area of the 9-factor test, this is where the risk of not meeting the Safe Harbor carries its most consequential tail.

Related Articles

• The Hobby Loss Rule Explained — the §183 safe harbor and the full 9-factor audit test
• Hobby Income: What It Is, How It’s Taxed — income tax, SE tax, and TCJA rules for hobby earners
• Hobby Tax Write-Offs: What Is and Isn’t Deductible — what the TCJA changed
• How to Report Hobby Income on Your Tax Return — filing mechanics
• Hobby Income and the 1099-K — how 1099 forms interact with hobby income
• Hobby Income and Self-Employment Tax — SE tax analysis

This article is for general informational purposes only and does not constitute legal or tax advice. Consult a licensed CPA or tax attorney for guidance specific to your situation.