If you bill clients as a consultant, the deductions that actually move your tax bill are a short list: home office, mileage, health insurance, retirement contributions, and the qualified business income (QBI) deduction. Everything else — the $40 software subscription, the coffee shop wifi — is rounding error unless you're buying serious equipment. This guide isn't a “50 write-offs” list. It's a decision map for three income levels, because what matters at $45,000 net looks nothing like what matters at $180,000 net.
The short verdict: below roughly the mid five figures, keep it simple — the simplified home office method, a tracked mileage log, and a low-maintenance retirement account cover most of the available benefit. In the low six figures, retirement plan design — solo 401(k) versus SEP IRA — becomes the single biggest lever you control. Above that, the conversation shifts from “which deduction” to “which entity and compensation structure,” and that's a conversation for a CPA, not a blog post.
The one rule that decides almost every deduction
The IRS standard for a deductible business expense is that it must be both ordinary and necessary — common in your line of work and helpful to running it. Personal expenses generally don't qualify just because you're self-employed and working from your kitchen table. Most solo consultants report income and expenses on Schedule C, and net self-employment earnings of $400 or more generally create a filing requirement — a lower bar than most freelancers expect, and one reason “I only made a little on the side” isn't a safe assumption.
That ordinary-and-necessary test is why “can I deduct this?” is almost always the wrong question. The better one is: can you document that the expense was for the business, and would another consultant in your field reasonably incur it? Keep receipts and a mileage log. A deduction is only as strong as the paper trail behind it.
The 3-persona true-cost model: what actually pays off at each income level
Here's the original test we ran this guide through. Instead of listing every possible write-off, we modeled three real consulting income levels and asked which deductions deliver enough tax benefit to justify the extra recordkeeping — or the extra professional fees — they require.
Persona A: the $45,000 side-hustle consultant
A part-time or early-stage consultant netting $45,000 typically has a modest, dedicated workspace and light business driving. Using the simplified home office method — $5 per square foot, capped at 300 square feet — a 150-square-foot office caps out at $750, well under the $1,500 ceiling that only kicks in at the full 300 square feet. Mileage matters more than people expect: a modest 1,500 business miles a year, using this year's blended standard mileage rate (72.5 cents through June 30, 2026, then 76 cents from July 1 onward), works out to roughly $1,100.
At this income level, retirement contributions and QBI optimization rarely justify a dedicated plan or an accountant's hourly rate. The QBI deduction — up to 20% of qualifying business income for many pass-through filers — is still worth claiming since a $45,000 net consultant clears the $1,000 minimum QBI threshold that applies for tax years beginning after December 31, 2025, easily. The bigger win here is simply not overbuying: no S-corp, no elaborate plan, just clean books.
Persona B: the $90,000 full-time consultant
A full-time solo consultant netting $90,000 usually has a real dedicated office, more client-facing driving, and enough margin to fund a retirement plan seriously. The simplified home office method now maxes out at the full $1,500 (300 square feet at $5 per square foot). Heavier mileage — say 5,000 business miles across the year at the blended 2026 rate — adds roughly $3,700.
This is where retirement plan choice starts to matter more than any other deduction on the list. For 2026, a solo 401(k) allows an employee elective deferral of up to $24,500, plus a separate employer contribution calculated on net self-employment income. A SEP IRA caps employer contributions at the lesser of 25% of compensation or $72,000 for 2026 — for a $90,000 net consultant, that ceiling isn't close to binding, but the SEP's simplicity is its real selling point. The self-employed contribution formula for either plan isn't a flat 25% of net profit — it runs through a specific worksheet — so this is a number to model with a CPA or plan provider, not one to napkin-math.
Self-employed health insurance premiums are deductible above the line on Schedule 1 using Form 7206, dollar for dollar, up to the earned income the business generates — but only for months when subsidized employer coverage wasn't available to the consultant. For someone paying their own premiums entirely, this is one of the largest deductions on the list, often larger than the home office and mileage combined.
Persona C: the $180,000 agency-of-one
At $180,000 net, the math changes in a way many consultants miss: for tax year 2026, the Social Security portion of self-employment tax applies to net earnings up to $184,500. A consultant netting $180,000 is still under that ceiling, meaning nearly all of their net income is exposed to the full self-employment tax rate — unlike someone earning well above the wage base, whose marginal SE tax rate effectively drops once they clear it. See our self-employment tax breakdown for how that math actually runs.
The home office deduction is still capped at $1,500 regardless of income — a fixed-dollar deduction stops scaling long before income does, which is part of why higher earners look toward entity structure instead of expense-chasing. Retirement contribution room does scale, though: 25% of $180,000 is $45,000, comfortably under the SEP's $72,000 ceiling for 2026, while a solo 401(k)'s added employee deferral piece (up to $24,500) can push total contribution room higher than a SEP alone, depending on the specific self-employed calculation.
One wrinkle worth flagging: the IRS treats consulting as a specified service trade or business for QBI purposes, which means the deduction can phase out at higher income regardless of the general 20% framework, and the exact income thresholds adjust most years. At $180,000, whether QBI applies in full, partially, or not at all depends on filing status and total taxable income — this is squarely a run-it-with-a-CPA number, not one to assume.
This is also the income level where S-corp election, payroll, and “reasonable salary” conversations typically start — a different operating model than the sole proprietorship this guide focuses on, and one that deserves its own analysis with a tax professional before electing anything.
| Persona | Net income | Home office (simplified) | Illustrative mileage | Retirement lever | QBI status |
|---|---|---|---|---|---|
| A — side-hustle | $45,000 | ≈ $750 (150 sq ft) | ≈ $1,100 (1,500 mi) | Low priority | Applies, minimal complexity |
| B — full-time solo | $90,000 | $1,500 (max, 300 sq ft) | ≈ $3,700 (5,000 mi) | Biggest lever — plan choice matters | Applies, verify with CPA |
| C — agency-of-one | $180,000 | $1,500 (max, unchanged) | Varies with travel | Highest dollar potential, most complex | Possible phase-out — CPA required |
Deduction-by-deduction: what's actually worth tracking
Home office deduction
The simplified method — $5 per square foot of dedicated office space, capped at 300 square feet — tops out at $1,500 a year as of the 2026 tax year. It requires the space to be used exclusively and regularly for business; a desk in the corner of a room used for anything else generally doesn't qualify, and the deduction can't exceed the gross income the home-office activity generates. It's not available for W-2 employees at all, only for self-employed filers — a relevant distinction if you consult on the side of a day job. More detail in our home office deduction rules breakdown.
Mileage and vehicle use
For 2026, the standard mileage rate is 72.5 cents per business mile from January 1 through June 30, then 76 cents per business mile from July 1 through December 31 — a consultant tracking miles across the full year is really working with a blended rate, not one flat number. Only business miles count: driving to a client site or a business meeting qualifies, but the daily commute from home to a primary workplace generally doesn't. The standard mileage rate is simple, but consultants with an expensive or heavily depreciated vehicle sometimes come out ahead using the actual-expense method instead — worth comparing once a year rather than assuming.
Self-employed health insurance
Self-employed consultants with net profit can generally deduct health insurance premiums for themselves, a spouse, dependents, and children under 27 above the line, using Form 7206 attached to Schedule 1. The deduction can't exceed the earned income the business generates, and it doesn't apply for any month the consultant was eligible for subsidized coverage through an employer plan — their own or a spouse's. Consultants operating through an S-corp face a different, more specific eligibility path for shareholders owning more than 2% of the company, which is another reason entity choice and deduction strategy are linked, not separate decisions.
Retirement: solo 401(k) vs. SEP IRA
Both plans are built for a business of one, and neither requires payroll to open — a meaningful solo-lens point, since a lot of retirement-plan content assumes employees exist. A SEP IRA allows employer contributions up to the lesser of 25% of compensation or $72,000 for 2026, and it's genuinely simple to open and fund with almost no ongoing administration. A solo 401(k) — sometimes called an individual or uni-401(k) — adds an employee elective deferral of up to $24,500 for 2026 on top of an employer contribution calculated using a self-employed-specific formula, which usually means more total contribution room for the same net income, at the cost of slightly more setup. Our full solo 401(k) vs. SEP IRA comparison walks through the tradeoffs.
Neither number is a flat percentage you can apply to gross revenue — the actual contribution limit runs through the IRS's self-employed calculation worksheet, which adjusts for the deductible portion of self-employment tax first. This is math worth confirming with a CPA or the plan provider directly before committing to a contribution amount.
The QBI deduction — and why “consultant” is a loaded word here
The qualified business income deduction can reduce taxable income by up to 20% of qualifying pass-through business income for many sole proprietors, partnerships, and S-corp owners — but “consultant” is one of the professions the IRS specifically treats as a specified service trade or business, which means the deduction can phase out at higher taxable income levels regardless of the general framework. For tax years beginning after December 31, 2025, there's also a new minimum QBI requirement of $1,000 layered on top of the existing rules. None of this makes QBI automatic, and the exact income thresholds shift often enough that stating a number here would go stale within a filing season — confirm your specific eligibility with a CPA rather than assuming the full 20%.
What about laptops, software, and big equipment purchases?
For the 2025 tax return most consultants file in 2026, the rules are notably generous for larger purchases: 100% bonus depreciation applies to qualifying property acquired and placed in service after January 19, 2025, and the Section 179 deduction allows up to $2.5 million of qualifying property to be expensed immediately, phasing down once total purchases exceed $4 million — a ceiling essentially irrelevant to solo consultants, but the 100% bonus depreciation provision matters if you bought a computer, camera, or other business equipment last year. These are 2025-year rules on a 2026-filed return, not the 2026-year rules covering income earned this calendar year — mixing the two up is one of the more common self-prep errors, and worth double-checking with a CPA if a large purchase is involved.
Skip these deductions if...
Skip the home office deduction if you don't have a space used exclusively for business — a shared kitchen table doesn't qualify, and claiming it anyway is a documented audit flag. Skip aggressive mileage claims if you can't produce a contemporaneous log; the IRS mileage rate is generous, but only with real records behind it. Skip a solo 401(k) over a SEP if you want zero ongoing plan administration and your net income is modest enough that the SEP's simpler percentage-based limit isn't actually constraining you. And approach the S-corp/entity conversation cautiously if your net consulting income is still in the $45,000-$60,000 range — the payroll and compliance overhead often outweighs the tax benefit until income is meaningfully higher, though the exact break-even is specific to your state and situation and should be modeled with a CPA, not guessed.
Where this fits in your financial OS
Tax deductions sit in the Foundation layer of a solo consultant's financial operating system — they don't generate revenue or protect against risk, but getting them wrong, or overcomplicating them, drains cash that should be funding the Flow and Growth layers instead. In practice, that means getting quarterly estimated taxes right first (see our guide to quarterly estimated taxes for consultants), keeping Schedule C clean (our Schedule C walkthrough covers the mechanics), understanding how self-employment tax interacts with every deduction above, and only then layering in the higher-leverage moves — home office and retirement plan design.
Bottom line
Consultant tax deductions aren't a scavenger hunt for receipts — they're a small set of levers that scale differently depending on where your net income sits. Below roughly $45,000-$60,000, simplicity typically wins: simplified home office, a real mileage log, and clean books. Between $60,000 and $150,000 or so, retirement plan design is usually the single biggest number you control. Above that, the conversation is less about which deduction and more about which structure — and that one is worth paying a CPA for before you file, not after.