100 Pesos Centenario de la Reforma Monetaria (2005)

If you inherited or found a Mexican 100 Pesos Centenario de la Reforma Monetaria dated 2005, here is the honest answer: it is a modern commemorative coin, not a rarity. In circulated shape it trades for roughly 6 to 30 US dollars. Only certified, high-grade examples push higher, and even those stay in the low hundreds. Nobody is retiring on this one.

That may not be what other pages tell you, but the numbers back it up. This is a 2005 issue, still very recent by numismatic standards, and modern Mexican commemoratives rarely appreciate the way people hope. Value here comes from condition and certification, not age.

What this coin actually is

The "Centenario de la Reforma Monetaria" translates to "Centennial of the Monetary Reform." It marks 100 years since Mexico's currency overhaul, which is why the coin exists. Do not confuse it with the famous gold Centenario (the 50 Pesos gold bullion coin worth thousands of dollars). Despite the shared word, they are completely different pieces. This one is not gold.

Here are the specifications straight from Banco de México (Banxico), the country's central bank:

Feature	Detail
Face value	100 Pesos
Year	2005 (single year of issue)
Weight	33.8 grams
Diameter	39 mm
Composition	Bimetallic
Edge	Discontinuous reeded (segmented)
Era	Nuevos Pesos / modern

Notice the composition: bimetallic, not silver and not gold. The outer ring and center core are base metals. That matters because it means the coin has no meaningful melt value. A silver coin has a bullion floor. This one does not. Its worth is purely collector demand.

What it is worth in 2026

Because it was minted recently and in circulating form, most examples you find are worth modest money.

Condition	Approximate value (USD)
Circulated, visible wear	6 to 30 dollars
Uncirculated (UNC), no wear	30 to 80 dollars
Certified MS-65 or higher (NGC / PCGS)	80 to 200+ dollars

A coin still sealed in its original Banxico blister pack (the mint's plastic packaging) will bring a premium over a loose, handled example. If yours has been in a pocket or a coin jar, expect the low end.

These are ranges, not fixed prices. A single certified grade point can double the value at the top of the scale, which is exactly why grading matters for this piece.

The mintage question

Banxico never published an official mintage figure for this issue. That absence is usually a sign the coin was released in limited numismatic sets rather than mass general circulation. Collector forums float numbers, but none are confirmed, so treat any "exact mintage" claim you see online with skepticism. What we can say is that it was a single-year, commemorative issue, which limits supply but does not make it truly scarce.

How to tell if yours is genuine

Start with the physical specs, they are the fastest filter:

• Weight: it must be 33.8 grams. Use a small digital scale.
• Diameter: 39 mm exactly.
• Edge: discontinuous (segmented) reeding, not a smooth or fully continuous edge.

If your coin misses those numbers, you likely have a fake or a damaged piece. Beyond that, compare the relief and lettering against official Banxico images. Counterfeits tend to have flatter, mushier detail. For any coin you think might hit the higher end of the value range, professional grading through NGC or PCGS is the definitive check. They authenticate and assign a grade in one step, which also raises resale value.

Errors: mostly a myth

Genuine mint errors (off-center strikes, die rotation, double strikes) can multiply a coin's value when they are real and verifiable. The catch: the vast majority of "errors" people post online are post-mint damage, meaning dings, corrosion, or wear that happened after the coin left the mint. That is not an error and adds no value. If you believe you have a true error, get it looked at by graders or the community before assuming it is worth anything.

Where to sell it (US and beyond)

Since this is a Mexican coin, your best market is where Mexican collectors are. Options, from safest to riskiest:

• A verified numismatic dealer from the Pesoteca shop directory. A dealer values it on the spot and pays fairly.
• The Pesoteca buy-and-sell forum, where you deal directly with collectors.
• Online marketplaces like eBay or Mercado Libre. Prices can be decent, but these platforms carry the most counterfeits, so buyers are cautious. Always post clear photos of the front, back, and edge.

Before you sell anything, check the coin grading guide so you know which value bracket your piece falls into. Do not dump it on the first Facebook lowball offer.

Have one of these sitting in a drawer and not sure what grade it is? Post clear photos on the Pesoteca forum and let collectors help you pin down its value before you sell.