Ask most dealers how a particular piece is doing profit-wise and you’ll get a shrug, or a rough gut feeling based on what it sold for versus a hazy memory of what they paid. That instinct is often wrong, sometimes by a wide margin, because it leaves out restoration costs, booth fees, shipping, transaction fees, and the time value of capital sitting in inventory that hasn’t moved in eight months.

Antiques dealing is unusually punishing for a business run on gut feeling, because unlike most retail, every single item has its own unique cost basis, its own holding period, and often its own restoration expense. Good bookkeeping isn’t a back-office chore here — it’s the difference between a business that looks busy and one that’s actually profitable.

Start With Real Separation Between Business and Personal Money

This is the single most common failure point, and it is also the easiest to fix. Dealers who run purchases, sales, booth rent, and gas money through a personal checking account create a mess that costs real money at tax time and makes it functionally impossible to know if the business is profitable at all.

The fix is mechanical, not conceptual:

  • Open a dedicated business checking account and, ideally, a business credit card, even as a sole proprietor
  • Run every inventory purchase, every booth or shop rent payment, every shipping and packaging cost through that account
  • Pay yourself a deliberate “owner’s draw” transfer from business to personal, rather than spending directly from business funds
  • Keep a small cash log for market or estate-sale purchases made in cash, and reconcile it weekly, not “eventually”

This separation alone makes tax preparation dramatically simpler and, more importantly, makes your profit and loss statement mean something. A business account that mixes in personal grocery runs and gas fill-ups produces a P&L that nobody, including you, can trust.

Understanding Cost Basis for Every Piece

Cost basis is the total amount you have invested in a specific item before it sells — not just the purchase price. For antiques specifically, this typically includes:

  1. The purchase price itself, whether from an estate sale, auction, wholesale source, or private seller
  2. Any buyer’s premium or auction fees paid at acquisition
  3. Restoration, cleaning, or repair costs directly tied to that item
  4. A reasonable allocation of transport costs, if you paid specifically to move that piece
  5. Framing, mounting, or presentation costs where relevant

Tracking this per item sounds tedious, and for a business moving hundreds of small items a month, exact per-item tracking isn’t always realistic. A workable middle ground many dealers use is a spreadsheet or inventory app with one row per item (or per lot, for smaller items bought in bulk), recording purchase date, source, purchase price, and a running restoration cost field updated as work is done.

The dealers who consistently make money on high-value pieces are not the ones with the best eye for a bargain — they’re the ones who actually know, to the dollar, what they have in a piece before they price it.

The Margin Math Dealers Skip

Two numbers get confused constantly in resale businesses: markup and margin. They sound similar and produce very different pictures of profitability.

Markup is profit expressed as a percentage of cost. Buy something for $100 and sell it for $200, and that’s a 100% markup.

Margin is profit expressed as a percentage of the sale price. That same transaction — $100 cost, $200 sale price, $100 profit — is a 50% margin.

The confusion matters because dealers pricing purely off markup instincts (“I always double my money”) can end up with margins that look fine on paper but collapse once selling costs are factored in. A $200 sale with a 20% marketplace fee, $15 in payment processing, and $25 in shipping supplies and packing time leaves considerably less than the “50% margin” implied by the raw numbers.

A more honest margin calculation for any sale:

  • Sale price
  • Minus item cost basis (purchase price + restoration + allocated acquisition costs)
  • Minus platform or marketplace fees
  • Minus payment processing fees
  • Minus shipping and packaging costs actually incurred
  • Minus a reasonable allocation of booth rent or shop overhead for the holding period

What’s left is your true net margin, and it is frequently ten to twenty percentage points lower than the “gut feeling” margin dealers report before they run the full math. Running this calculation on your ten highest-dollar sales from the last quarter is usually enough to reveal whether your pricing intuition matches reality.

Aging Inventory Is a Hidden Cost

Every item sitting unsold in a booth or storage unit represents capital that isn’t working — money that could have been reinvested in faster-moving stock. Bookkeeping systems that track only sales, not inventory age, miss this entirely.

A simple aging report — how long each unsold item has been in inventory, sorted oldest to newest — surfaces two useful things. First, it flags pieces that may be overpriced or poorly presented, since genuinely well-priced antiques in good condition typically move within a predictable window for their category. Second, it quantifies exactly how much capital is currently tied up in slow-moving stock, which matters enormously when deciding whether to fund a new buying trip or an estate sale purchase.

Dealers who review an aging report monthly tend to develop much sharper pricing instincts over time, because they get direct, repeated feedback on which price points and categories move versus which ones stall.

Simple Software That Actually Fits This Business

Most mainstream small-business accounting software is built with a generic retail or service business in mind, and dealers often over-invest in features they don’t need or under-invest in inventory tracking they do need. A workable stack for most independent dealers:

  • QuickBooks Online or Wave for core bookkeeping — bank feeds, expense categorization, and profit and loss reporting. Wave is free and sufficient for many small operations; QuickBooks scales better once you have employees or multiple sales channels.
  • A dedicated inventory spreadsheet or a lightweight inventory app (many dealers still use a well-structured Google Sheet successfully) for per-item cost basis, acquisition source, and aging, since general accounting software rarely tracks unique-item inventory well.
  • A separate folder or app for receipts, photographed at the point of purchase — a receipt scanning app tied to your bookkeeping software saves hours at tax time and protects you if a paper receipt fades or gets lost.

The goal isn’t sophistication for its own sake. It’s a system simple enough that you’ll actually use it consistently, because a perfect bookkeeping system that gets abandoned after six weeks is worth less than a basic one maintained faithfully for years.

Setting Aside Money for Taxes as You Go

Independent dealers, particularly those newly full-time, consistently underestimate quarterly tax obligations because the business income arrives unevenly — a great month at a major show followed by a quiet month can create the illusion that the good month’s income is all spendable.

A disciplined habit that prevents the spring tax surprise: transfer a fixed percentage of every sale, deposited immediately into a separate savings account earmarked only for taxes, the moment the sale clears. Many dealers use something in the range of 25–30% of net profit as a starting estimate, adjusted once an accountant has reviewed a full year’s actual tax liability. This single habit, more than any software choice, is what keeps dealers from facing a tax bill they can’t cover.

Reviewing the Numbers on a Schedule, Not Just at Tax Time

Bookkeeping done only in a panic each April produces worse decisions all year, because the dealer is flying blind on margins, aging inventory, and cash flow the rest of the time. A short monthly review — twenty minutes with a cup of coffee, looking at total sales, gross margin, and the aging report — is enough to catch problems early: a category that’s stopped moving, a fee structure eating more than expected, or a cash crunch approaching before it becomes urgent.

The dealers who treat their bookkeeping as a monthly habit rather than an annual ordeal consistently report clearer decision-making about what to buy next, what to reprice, and when they can actually afford to take on a bigger piece of inventory. In a business built on unique, illiquid assets, that clarity is worth more than almost any single sourcing skill.

Handling Multi-Item Lots and Job Lots Without Losing Your Mind

Estate sales and auction lots rarely arrive as single, cleanly priced items. A dealer might pay $600 for an entire box lot containing fifteen pieces of varying value, and the instinct to skip cost-basis tracking on these purchases entirely — treating them as one lump expense — is understandable but expensive in the long run, because it makes it impossible to know which categories or sourcing venues are actually profitable.

A workable compromise, used by dealers who buy lots regularly, is proportional allocation: estimate each item’s likely resale value relative to the others in the lot, then divide the total purchase price across items in that proportion rather than splitting it evenly. A $600 lot containing one piece expected to sell for $400 and fourteen smaller pieces expected to sell for $20–40 each should not have its cost basis split fifteen ways evenly — the standout piece should absorb a proportionally larger share of the cost. This takes a few extra minutes per lot but produces cost-basis numbers that actually mean something when it’s time to price and evaluate performance.

Where a Bookkeeper or Accountant Earns Their Fee

Plenty of dealers handle day-to-day categorization and inventory tracking themselves, and that’s appropriate — nobody knows the business better. But a few moments call for professional help, and paying for it is usually cheaper than the mistakes it prevents:

  • Setting up your chart of accounts correctly at the start, so categories like inventory, cost of goods sold, and restoration expenses are structured the way an accountant will actually want them at tax time
  • Determining whether you should be taxed as a sole proprietor, LLC, or S-corp once revenue reaches a level where the choice starts to matter
  • Handling sales tax collection and remittance across states if you sell at shows or ship to buyers in multiple jurisdictions, since rules vary significantly and getting this wrong creates real liability
  • An annual review comparing your self-tracked numbers against what a professional would calculate, catching drift before it compounds over several years

A good bookkeeper or accountant familiar with resale or inventory-based businesses — not just a generalist — is worth seeking out specifically, since the nuances of cost basis and inventory valuation in this trade differ meaningfully from a typical service business their default templates are built around.