What you need to prove what your gold cost you

The so-what: when you sell gold, you are taxed on the profit, not on the whole sale. Profit is what you sold it for minus what you paid. That second number is called your cost basis, and it is only worth anything if you can prove it.

Why a lost receipt is expensive

Say you bought a 10 gram bar for $6,000 and sold it years later for $8,000. You made $2,000, and that is what you should be taxed on.

Now lose the invoice. With nothing to show what you paid, a tax authority can treat your cost as zero and assess the full $8,000 as gain. You pay tax on $6,000 you never made, purely because a piece of paper went missing.

This is not a rule in one country. It is what happens anywhere the burden of proving your own cost sits with you, which is almost everywhere.

What to keep, per bar

Five things. Keep them together, and keep them for as long as you hold the metal plus however long your country expects you to keep records.

• The invoice or receipt, showing the price you actually paid.
• The date you bought it. How long you held it often changes the treatment.
• The weight and purity, for example 10 g at 999.9.
• The serial number, if the bar has one.
• The costs on top, such as dealer premium, shipping or assay fees. These usually count toward your basis, which means they reduce the taxable gain.

Why the serial number matters more than people think

If you own several bars bought at different prices and sell one, which one did you sell? The answer changes your tax bill.

With no records you fall back to a default rule, commonly first-in first-out: the oldest bar is treated as the one sold. If that was your cheapest, you have just handed yourself the largest possible taxable gain.

With a serial number, an invoice and a date, you can point at the exact bar and say that one. This is called specific identification, and it is the method that usually saves the most, because it lets you choose honestly rather than by default.

The part people get wrong

Cost basis is not the gold price on the day you bought. It is what you paid, premium included. Two people buying identical bars on the same morning can hold different bases, because one paid a higher dealer margin.

It also does not move. The spot price changes every day; your basis is fixed on the day you bought and stays there until you sell.

Work out what you would make

Put your own numbers in with the free Gold Profit Calculator. It shows your gain from what you paid and what you would sell for. The tax rate is a field you fill in yourself, because that depends on where you are and we are not going to guess it.

FiLot is a bookkeeping tool, not a tax adviser. Tax treatment of gold differs by country and changes over time. This page explains what records to keep, not what you will owe. For your own position, ask someone qualified where you live.

Next: how to buy gold on Solana, and what tokenised gold asks you to trust that a bar in your hand does not.