1985 Mexican 100 Pesos Coin: Value & What It's Worth

If you inherited or found a 1985 Mexican 100 pesos coin, here's the honest answer first: in worn, circulated condition it's worth under a dollar, usually just its face value as a collectible. This is a common circulation coin, not a rare treasure. But condition changes the picture, and a flawless uncirculated example can bring a few dollars from the right buyer.

What this coin actually is

The 1985 100 pesos is a large bronze-aluminum coin from the old peso era, before Mexico's 1993 currency reform that created the "new peso" (nuevo peso) and lopped three zeros off the currency. So this is a pre-reform coin. It is not silver and it is not gold. It's an alloy of bronze and aluminum, which gives it a golden-yellow color that fools a lot of people into thinking it's precious metal. It isn't.

Key specs, straight from Banco de México:

• Metal: bronze-aluminum (aluminum bronze alloy)
• Weight: 11.8 grams
• Diameter: 26 mm
• Edge: interrupted reeding (segments of reeding around the rim)
• Mint: Casa de Moneda de México, the mint that has struck coins continuously since the 16th century
• Catalog reference: KM# 493

How much is a 1985 100 pesos worth in 2026?

Straight talk: this coin was minted in large numbers and millions survive, so rarity is not on your side. Metal content adds nothing here, aluminum bronze has no bullion value to speak of. What little value exists comes almost entirely from condition.

Condition	What it looks like	Approximate value (USD)
Circulated (worn)	Scratches, dull, everyday wear	Under 1 dollar
About uncirculated	Light handling, most detail sharp	1 to 2 dollars
Uncirculated (MS)	Full luster, no wear	2 to 5 dollars
Certified high grade (MS65+)	Graded by NGC or PCGS, top pop	10 to 25 dollars

These are collector-market figures, not guarantees. A raw coin from a jar sells for pocket change. The only way it climbs is if it's genuinely uncirculated and, ideally, professionally graded. For most people who inherited a box of these, the realistic answer is that they're worth keeping as a curiosity, not cashing in for a windfall.

The "it's gold" myth

The golden color makes people assume this is a gold coin. It is not. Mexico does have famous gold coins, the Centenario (50 pesos gold) and modern gold bullion, but this 100 pesos is a base-metal circulation coin. If someone offers to buy it "because it's gold," they're either mistaken or hoping you are. Don't confuse the color with the content.

Are there valuable minting errors?

Genuine mint errors, off-center strikes, die rotation, double strikes, real varieties, can multiply the value of any coin, including this one. But be realistic. Most of the "errors" people post online are post-mint damage: dings, corrosion, scratches from decades in circulation. That's not an error and it lowers value, it doesn't raise it. If you think you have a true error, photograph it clearly and post it to the Pesoteca forum so collectors can verify before you get your hopes up.

How to tell if yours is genuine

Counterfeits of a low-value circulation coin are uncommon, but if you want to check:

1. Weigh it. A jeweler's scale should read 11.8 grams. Off by more than a fraction of a gram is a red flag.
2. Measure the diameter. It should be 26 mm on calipers.
3. Check the edge. It has interrupted reeding, segments of reeding rather than a fully reeded edge.
4. Look at the relief. Genuine coins have crisp, well-defined detail. Fakes often show flat, mushy relief or uneven color.

Where to sell it

If you decide to sell, skip dumping it to the first Facebook buyer. Your best options:

• A verified numismatic shop from the Pesoteca dealer directory, where you get an on-the-spot appraisal without a middleman markup.
• The Pesoteca buy-and-sell forum, where you deal directly with collectors.

Before you sell anything, photograph the obverse, reverse, and edge in good light, and compare your coin's condition to the table above so you know what a fair price looks like. For a common coin like this, don't expect much, but knowing the grade keeps you from getting shortchanged if yours happens to be a pristine example.

Got a jar of old Mexican coins and not sure what's in it? Post your photos in the Pesoteca forum and let the community tell you which ones are worth a second look.