IRC Section 280E is brutal. It strips cannabis businesses of virtually every deduction available to every other legal operation in the country. But there's one exception — Cost of Goods Sold (COGS). And if you know how to calculate it correctly, that's the loophole that keeps your business viable.
This guide walks you through the process step by step. No jargon for jargon's sake. Just the mechanics of what counts, how to allocate it, and where operators most commonly get it wrong.
Before you start: If you haven't yet read our intro to IRC 280E, this guide assumes you understand why COGS is the only deduction available to cannabis businesses. The calculation only matters if the underlying logic is clear.
Why COGS Is the Only Number That Matters
For most businesses, taxes are calculated on net profit: Revenue minus all operating expenses equals taxable income. Cannabis businesses can't play that game. 280E eliminates all operating deductions — rent, payroll, marketing, professional fees — and leaves only one path: Gross Receipts − COGS = Taxable Income.
Every dollar correctly classified as COGS is a dollar that escapes the 280E tax burden entirely. Miscalculate your COGS, and you're either leaving money on the table (under-claiming deductions) or inviting an IRS audit (over-claiming). Getting it right is the most important financial task for any cannabis operator.
COGS = Beginning Inventory + Purchases / Production Costs − Ending Inventory
IRC Section 471 — Inventory Accounting RulesStep 1: Identify Your Direct Costs
Direct costs are the expenses that go directly into producing or acquiring the product you sell. These are always COGS-eligible, regardless of business type.
Direct costs by business type
Dispensary / Retailer: The cost of inventory you purchased from a cultivator or processor — the wholesale price of the product you put on your shelves. Transportation to get it there. Quality testing if required before it hits the sales floor. That's your entire direct cost base.
Cultivator / Grower: Every expense tied to growing plants. Seeds and clones, grow media, nutrients, water, electricity for the grow facility, labor for planting and harvesting, equipment depreciation for grow technology. Everything that touches the plant before it goes to the processor or consumer.
Processor / Manufacturer: Raw material costs (flower or trim purchased from cultivators), extraction solvents and consumables, direct labor for manufacturing, packaging materials that become part of the final product, equipment depreciation on production machinery.
- Wholesale product cost (dispensary)
- Seeds, clones, mother plants (cultivator)
- Growing media, nutrients, water (cultivator)
- Direct production labor (cultivator + processor)
- Electricity for production space (cultivator + processor)
- Extraction equipment and consumables (processor)
- Packaging materials (all types)
- Quality assurance testing fees (all types)
Example: A cultivator spends $400,000 on grow supplies, $180,000 on direct production labor, $95,000 on facility electricity for the grow rooms, and $40,000 on equipment depreciation for cultivation equipment. Their total direct COGS-eligible costs = $715,000 before accounting for inventory adjustments.
Step 2: Allocate Shared Costs Between COGS and Operating Expenses
This is where most operators either leave money on the table or create audit risk. Shared costs — expenses that serve both production and non-production functions — must be allocated carefully and consistently.
How to allocate shared costs
Facility rent: If your building houses both a grow operation and a retail/dispensing area, only the portion of rent attributable to production square footage counts as COGS. Measure your grow space as a percentage of total facility square footage.
Utilities: Same principle — allocate electricity, HVAC, and water based on the proportion of your facility dedicated to production. A cultivation facility using 60% of its square footage for production and 40% for office/retail would allocate 60% of its utility costs to COGS.
Supervision labor: Managers who oversee production employees should have a proportional share of their wages allocated to COGS. If your head grower spends 100% of their time supervising production, their entire salary is COGS. If they split time 60/40 with administrative tasks, 60% is COGS.
Insurance and equipment: Production equipment insurance, production-area repairs, and maintenance on production equipment all flow into COGS. General liability insurance for the whole business does not.
- Production facility rent (allocated by square footage)
- Utilities for production space (allocated by usage)
- Supervision labor (allocated by time spent)
- Production equipment insurance and repairs
Consistency rule: Pick your allocation methodology once and document it. Square footage is the most common and most defensible — it's objective, measurable, and auditable. Switching methods year-to-year without documentation invites scrutiny.
Step 3: Calculate Your COGS Deductible Amount
Once you've identified direct costs and completed your allocation, you calculate COGS using the inventory formula:
COGS = Beginning Inventory + All Capitalized Costs − Ending Inventory
Capitalized costs = direct costs + allocated shared costsYear-end inventory true-up
Your COGS calculation isn't complete until you've reconciled actual inventory. At year-end, conduct a physical count of unsold product. The difference between your book inventory and physical count affects your final COGS figure. Discrepancies require explanation — unexplained inventory shrinkage gets flagged.
Beginning inventory (start of year) should equal the prior year's ending inventory. If you're a new business, beginning inventory is zero. Work-in-progress and finished goods both count toward your ending inventory balance.
Ending inventory (end of year): Value unsold product at your cost basis — what you actually spent to produce or acquire it, including your allocated shared costs. Do not use retail or wholesale market value. The IRS wants your actual cost, not replacement cost.
Example — Dispensary: Beginning inventory $0. Direct inventory purchases (wholesale) $1,200,000. Transportation and testing fees (direct) $40,000. Ending inventory count $180,000 (at cost). COGS = $0 + $1,240,000 − $180,000 = $1,060,000. Taxable income = Gross Receipts − $1,060,000.
Example — Cultivator: Beginning inventory $0. Direct costs $715,000. Allocated facility rent (production share) $84,000. Allocated utilities (production share) $38,000. Ending inventory (work-in-progress + finished goods) $210,000. COGS = $0 + $837,000 − $210,000 = $627,000.
Step 4: Avoid the Most Common Mistakes
COGS calculation errors fall into a predictable pattern. Here's what to watch for:
Common errors that cost operators money
Missing indirect cost allocation: Many operators identify their direct costs correctly but ignore the indirect costs — facility overhead, utilities, supervision — that should also be capitalized into inventory. This understates COGS and overstates taxable income. The missed deduction can be significant for cultivators and processors.
No time tracking for split-role employees: Employees who work both production and non-production roles (common in smaller operations) need time logs. Without them, the IRS can disallow your entire labor allocation. "We estimate" is not a defensible methodology.
Over-claiming COGS for non-production costs: Conversely, some operators include executive salaries, corporate overhead, or marketing expenses in their COGS calculation. This is aggressive, easily challenged, and creates real audit exposure. COGS is limited to production and acquisition costs.
Skipping the year-end inventory count: A physical count is required for any inventory-based business under IRC 471. Using "book inventory" without a physical reconciliation is a red flag. If your accounting software shows $250K in ending inventory but your shelves show $180K, you need to explain the difference — or take the write-down.
Inconsistent year-to-year treatment: If you used square footage to allocate rent in 2024 and switched to labor hours in 2025 without a documented reason, the IRS will question both years. Document your methodology, apply it consistently, and update it only when circumstances genuinely change.
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Try the Free 280E CalculatorWhat Happens After You Calculate Your COGS
Once you have your COGS figure, the math is straightforward: Taxable Income = Gross Receipts − COGS. From there, your federal income tax applies to that number. The effective tax rate for a cannabis business depends on your total revenue, COGS base, and state tax treatment.
For most operators, the real value of a COGS calculation isn't just the number — it's the visibility. Running your numbers quarterly (not just at tax time) means you can make operational decisions with accurate tax exposure in mind. Hiring that additional employee, expanding your grow space, or adding a processing line all have 280E implications that compound over the year.
The TrimBooks calculator walks through all of this — classifies your expenses by COGS vs. non-deductible, handles allocation for shared costs, and produces an estimated tax liability. It's not a replacement for a cannabis-specialized CPA at filing time, but it gives you a clear picture of where you stand before expensive professional time is engaged.
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