The Premium / Unit field on the Record Purchase form is the one place new users most often pause. It looks like it might want the total you paid, or the per-unit total.
This article is the long version of what to enter, why the form is built this way, and how to translate from whatever your dealer invoice tells you into the number the form actually wants.
For the broader walkthrough of the form itself, see How to record a purchase.
The rule, in one line
Enter the premium per unit in dollars — the per-coin or per-bar markup over the metal's spot price at the time of your purchase. Not the per-unit total price, not the all-in transaction total, just the dollar amount above spot.
If you only know the all-in total, the next section walks through how to compute premium from it. The math is one line of arithmetic, and the form does the rest.
Why the form is built this way
A bullion purchase has two components rolled into one price: the melt value (what the underlying metal would be worth at spot) and the premium (everything else, like minting, distribution, dealer margin, scarcity, and condition). The all-in price you paid is the sum of those two.
Recording premium and spot separately, rather than just the all-in total, has three concrete benefits:
See how much you paid over market value. Storing them separately means you can see how much you paid above the metal itself.
Premium-over-spot is the actual measure of dealer cost. When you compare two dealers, what matters is what they charged above the metal value, not the headline price, which depends on what spot was doing that day.
Cost basis stays clean. If you sell an item, your cost basis is weight × spotAtPurchase + premium. Recording premium and historical spot separately means cost basis is unambiguous and reproducible for every item.
The form does the work. Once you enter premium and confirm spot, the per-unit price and the line total compute themselves.
Computing premium from a total price
If your dealer invoice shows per-unit price (or per-unit price + shipping), and you don't know the premium offhand, the formula is:
premium per unit = pricePerUnit − (weightOz × spotAtPurchase)
Where:
pricePerUnit: What you paid for one coin or one bar.
weightOz: The catalog's metal-content weight for the product (e.g. 1 oz for a 1 oz Gold Eagle). The catalog stores pure metal content, not the coin's gross weight, so you don't need to multiply by purity. That math is already baked into the weight figure.
spotAtPurchase: The USD spot price per troy ounce on the day of the purchase.
The result is the per-coin or per-bar premium. Plug that into the form, confirm the auto-filled spot is right (or override it for a historical purchase), and the form computes everything else.
A useful aside: because the catalog records metal content directly, a 1 oz American Gold Eagle (22 K, ~1.09 oz gross weight) and a 1 oz American Gold Buffalo (24 K, 1 oz gross weight) have the same melt value at a given spot price. Both have weightOz = 1.0.
Purity is shown on the catalog page as informational (so you can tell a 22 K coin from a 24 K coin), but it doesn't enter the melt math.
Worked examples
A few worked examples across metals and sizes, to anchor the math.
Example 1: A current Gold Eagle purchase
You buy 5 American Gold Eagles for $2,510 each. Spot is $2,400/oz. The 1 oz Eagle has weightOz = 1.0 in the catalog (1 oz of gold content, even though the coin's gross weight is closer to 1.09 oz because of the alloy).
Melt value per coin: 1 × $2,400 = $2,400
Premium per unit: $2,510 − $2,400 = $110
Enter 110 in Premium / Unit, 5 in Qty, and leave spot at the auto-filled current $2,400. The form shows a line total of $12,550, of which $12,000 is melt and $550 is premium.
Example 2: A current Gold Buffalo purchase
You buy 1 American Gold Buffalo for $2,505. Spot is $2,400/oz. The 1 oz Buffalo has weightOz = 1.0 in the catalog — same as the 1 oz Eagle, despite being a 24 K coin instead of 22 K. The catalog records metal content, not gross weight, so both coins have the same melt value at any given spot.
Melt value per coin: 1 × $2,400 = $2,400
Premium per unit: $2,505 − $2,400 = $105
Enter 105 in Premium / Unit, 1 in Qty. The form's line total comes out at $2,505.
Worth noting: the Buffalo and the Eagle in this and the previous example have the same melt value because both carry 1 oz of gold. The Buffalo's $105 premium is genuinely smaller than the Eagle's $110 because the dealer priced it more keenly, not because of any purity math the app is doing.
Example 3: A 10 oz silver bar
You buy a 10 oz Valcambi silver bar for $310. Spot is $28/oz. The bar has weightOz = 10.0 in the catalog.
Melt value: 10 × $28 = $280
Premium per unit: $310 − $280 = $30
Enter 30 in Premium / Unit, 1 in Qty.
Example 4: A fractional gold coin
You buy 2 American Gold Eagle 1/10 oz coins for $290 each. Spot is $2,400/oz. The 1/10 oz Eagle has weightOz = 0.10 in the catalog.
Melt value per coin: 0.10 × $2,400 = $240
Premium per unit: $290 − $240 = $50
Enter 50 in Premium / Unit, 2 in Qty.
Fractional coins almost always have higher percentage premiums than 1 oz pieces — the minting cost is similar, but it's spread over a smaller amount of metal. Here, $50 over $240 of metal is roughly 20% above spot, against the ~4.6% the same coin would carry in its 1 oz form.
The dollar premium will look reasonable; the percentage will look high, which is normal.
The spot price field
Sitting next to the Premium / Unit field is the Spot Price field. It's the per-troy-ounce spot price in USD at the time of your purchase, and it works hand-in-hand with the premium field.
Today's purchase: Leave the auto-filled current spot alone. The form uses live spot from the dashboard ticker.
Historical purchase: Override the auto-filled value with the historical spot for the purchase date. You can find this on your dealer invoice (most include it) or from any public spot chart for the metal.
Always USD per troy ounce. Even if your display currency is GBP or EUR, this field expects USD per troy ounce.
The historical spot you enter only affects your cost basis and the recorded premium for the purchase. The current value of every held item is always recalculated against today's live spot, regardless of what spot was on the day you bought.
How premium shows up later
Once a transaction is recorded, the premium per unit is preserved on the line and surfaced across the app:
Transactions History page: Each line of an expanded transaction shows the spot at time of purchase, the price per unit, and the premium per unit (both dollar amount and percentage above melt).
Holdings page: Premium-related figures show up alongside the current value, so you can see at a glance how much of your cost was above melt.
CSV exports: Premium per unit and percentage premium are included as columns in transaction exports, useful for spreadsheet comparison across dealers.
Analytics page: Some breakdowns use premium-over-spot to inform allocation and performance charts.
In short, the premium number you enter once stays with the item for as long as you hold it, and underpins every "how well did this purchase actually do" comparison.
A few edge cases
A handful of situations come up often enough to be worth calling out specifically.
You bought right at melt. Some 100 oz silver bars and large kilo gold bars trade at or very close to melt. In that case, enter $0 for premium. The form accepts a zero premium and treats the purchase as melt-only.
You bought below melt. Distressed sales, scrap, peer-to-peer deals at a discount, or just a very motivated seller — sometimes you pay less than the spot value of the metal. In that case, enter a negative number for premium (e.g. -15 if you paid $15 below melt). The form handles negative premiums correctly; the line total will be lower than melt, and your cost basis reflects what you actually paid.
You're recording a junk silver purchase. Junk silver uses a different melt formula — face value × multiplier × spot, instead of the weight × spot formula above. The premium math still works on the same per-unit-above-melt principle, but the melt baseline is computed differently because the catalog anchors pre-1965 US coins on face value rather than on a metal-content weight figure. The form does this automatically when you pick a junk silver catalog entry.
The dealer invoice shows premium as a percentage, not dollars. Convert it before entering: premiumDollars = pricePerUnit × (percentage / (100 + percentage)). Or skip the percentage entirely and use the all-in price approach from the Computing premium section above.
The most common entry mistake
By far the most common mistake on this form is entering the per-unit total price into the Premium / Unit field. The form treats whatever you enter there as premium-over-melt, so if you put your full $2,510-per-coin price into Premium / Unit, your cost basis comes out as roughly two times the actual price you paid (because the form adds melt value on top of what it thinks is your premium).
The single best check before clicking Record Purchase is the Total Cost figure in the totals strip at the bottom of the form. Compare it against what your dealer invoice says.
If they're roughly the same, you're fine. If the Total Cost is much higher (often close to 2×), you've almost certainly entered total price in the premium field by mistake — go back and recompute the premium.
The form will accept the entry either way — there's no automatic guard against it — so this is the one place where a glance at the totals strip before submitting saves the most rework.
Where to go next
How to record a purchase: The full Record Purchase form walkthrough.
Understanding melt value: The melt-value formula in plain English, with worked examples across metals.
How junk silver melt value is calculated: The face-value × multiplier × spot formula for pre-1965 US coins.
Adding shipping and handling costs: How shipping is allocated across line items.