$66.01 / troy oz
Spot as of Sep 6, 2026 10:00 PM · $1 move in silver changes this coin by $0.39
PhotoNot on file yet — specs below are mint weight.
Melt / coin$25.46
Silver spot$66.01
ASW0.38565 oz
Gross weight16.660 g
Fineness72%
Gross troy oz0.5356
Coins / oz2.59
What this coin is
The reduced UN PESO of 1920–1945 is 16.66 g, .720 fine, about 0.3856 oz ASW. Still reads UN PESO. Not the Caballito and not the Morelos .500 peso.
What is written on the coin
UN PESO, cap and rays or related liberty types, .720 era. Search un peso.
Metal content (the melt spec)
Mint specification: 16.6600 grams at 72% fine, which is 0.38565 troy oz of pure silver (ASW). Formula: grams × fineness ÷ 31.1034768. Date and mintmark do not change that number. Melt today is $25.46 per coin at $66.01 silver.
Mintage
High mintage across many dates. Usually near melt unless uncirculated.
A little history
Silver per peso was cut after World War I. This is the common “un peso” in junk silver lots.
How to tell you have this type
Smaller and lighter than Caballito / 8 reales. Date 1920–1945.
Date and mintmark do not change the metal on this page. Collector value is a different market — see Sold Comps for sold prices.
Before you sell
Usually near melt
If the coin is damaged or heavily worn, melt is a fair starting number. If it looks special, check collector solds before you sell.
Melt is the metal floor. For auction and eBay solds on the same type, see Sold Comps. We list 355 melt values; collector premiums are a different market.
Quick amounts
Using $66.01 silver.
| You have | Pure oz | Melt |
|---|---|---|
| 1 coin | 0.3857 | $25.46 |
| 10 coins | 3.8565 | $254.57 |
| 20 coins | 7.7130 | $509.14 |
Silver chart
Where silver has been.
Melt alert
Email me if this coin’s melt crosses a number I set.
Questions people ask
How much pure silver is in a Mexico peso 0.720 (UN PESO)?
Mint spec is 16.660 grams at 72% fine, which is 0.38565 troy oz of pure silver (ASW). Date and mintmark do not change that.
What is a Mexico peso 0.720 (UN PESO) worth in melt today?
At silver spot of $66.01 per troy oz, one coin’s melt is $25.46. Multiply by how many you have. A rare date or a nice grade can sell for more than melt.
How many Mexico peso 0.720 (UN PESO)s equal one ounce of silver?
About 2.59 coins equal 1.00 troy oz of pure silver at mint weight.
Does mintmark change the melt value?
No. Mintmark and date do not change the metal for this composition. A Mexico City (Mo) piece and another mint of the same spec have the same melt. Collector premiums still follow date, mint, and grade.
Is melt what I should sell this Mexico peso 0.720 (UN PESO) for?
Most common circulated examples trade close to the metal. Better grade, proofs, and scarce dates are the exceptions. If the coin is damaged or heavily worn, melt is a fair starting number. If it looks special, check collector solds before you sell.
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