Mexican & British Silver Coin Calculator — Values by Year

Inherited a tin of old Mexican pesos or British shillings and have no idea what they're worth? You're in the right place. A Mexican silver coin calculator and a British silver coin calculator both work on the same principle — find the coin's silver content, then multiply by spot — but each country hides that content behind its own dates and markings. This guide gives you the exact silver weight of every major Mexican and British coin, the simple date rules that tell silver from base metal, and the melt math at $75/oz.

Introduction: Foreign Silver Coins Overview

Mexico and Britain both minted circulating silver coins for centuries, then phased silver out within a few decades of each other — Britain by 1947, Mexico by 1977. That leaves millions of old coins floating around in drawers and inherited collections, many of them genuinely valuable for their metal alone.

The challenge is that neither country makes it obvious. Mexican coins often stamp their purity right on the face ("Ley .720"), while British coins give you nothing but a date — and you're expected to know the rules. Once you learn those rules, a foreign silver coin calculator turns a mixed jar into a dollar figure in minutes. We'll use a working silver spot price of $75 per troy ounce throughout so every melt figure stays consistent; scale any result by (your spot ÷ 75) for today's price.

Mexican Silver Coins — Pesos & Libertads

Mexico's great advantage is honesty: most 20th-century peso coins state their fineness directly on the coin. Look for the word "Ley" (Spanish for "law" or legal standard) followed by a decimal — "Ley .720" means 72% silver, "Ley .900" means 90%. This makes a Mexican silver coin calculator refreshingly straightforward, because the coin tells you its own purity.

The catch is that purity dropped over time. Early peso coins held more silver; reforms in 1905, then the 1940s, then 1977 steadily reduced it. Here are the main circulating coins and their actual silver weight (ASW) at $75/oz — everything you need to check a Mexican peso silver value at a glance.

ASW = actual silver weight. Melt values at $75 spot. Early 8 Reales and pre-1905 coins ran even higher (~.903) and usually carry collector value above melt.

The 1947–48 Cinco Pesos "Cuauhtémoc" and the 1955–60 Diez Pesos "Hidalgo" are the heavyweights of Mexican junk silver — chunky 90% coins worth real money in melt alone. The modern Libertad is a different animal entirely: a .999 fine bullion coin that tracks spot like an American Eagle, not a circulated peso.

British Silver Coins — Pre-1947 Sterling

British coins flip Mexico's approach: they tell you nothing on the coin, so you live or die by the date. A British silver coin calculator really comes down to one golden rule that every UK coin collector memorizes:

That single date split does most of the work. The denominations that contain silver are the crown, double florin, half crown, florin, shilling, sixpence, and threepence. Here is the exact British silver coin value of each by silver weight, in both eras, at $75/oz — the table most British calculators bury or skip entirely.

Silver weights are actual silver content (ASW). The 1920–46 coins weigh the same as their sterling versions but hold half the silver. Threepence ≈ half a sixpence.

Pre-1920 British .925 Silver Coins

Anything struck in 1919 or earlier is the good stuff — full sterling silver, 92.5% pure, the same standard as quality British flatware. These are the highest-value circulated British coins by silver content, and the larger denominations carry serious weight.

Because they're both older and purer, pre-1920 coins frequently cross from "melt value" into "collector value." A common-date Victorian shilling trades near melt, but a scarce date or a high-grade example can be worth multiples of its silver. Always check dates before selling pre-1920 British silver as scrap.

1920–1946 British .500 Silver Coins

After World War I, soaring silver prices forced Britain to halve the silver in its coins. From 1920 to 1946, circulating "silver" coins were just 50% silver, alloyed with copper and sometimes manganese. That manganese is a handy tell — these coins often tarnish to a dark, almost black tone, unlike the gentler grey of sterling.

They still hold real silver value — half that of their pre-1920 counterparts, coin for coin. A 1935 florin is worth about $13.64 in melt at $75 versus $25.23 for its 1915 equivalent, despite weighing the same number of grams. The maths is the same weight-times-purity formula; only the 0.500 multiplier changes. Note one exception: Maundy coins (ceremonial issues) stayed sterling throughout, so a 1930s Maundy set is 92.5%, not 50% — and Maundy sets carry strong numismatic value far above their melt.

Mexican Libertad Bullion Series

The modern Libertad stands apart from old peso coinage. Minted by Banco de México since 1982, it's a .999 fine silver bullion coin sold by weight, available from 1/20 oz up to 1 kilo, with the 1 oz version the most common. Its design — the Winged Victory angel with twin volcanoes — is among the most admired in bullion.

Unlike a worn .720 peso valued purely on scrap, a Libertad trades at spot plus a premium, like any modern bullion coin. Low-mintage dates and proof versions command strong collector premiums on top of melt. If you're holding Libertads, value them as bullion (spot × weight + premium), not as junk silver. For how bullion premiums work in detail, see our silver bullion calculator guide.

How to Identify Mexican vs British Silver

Telling these coins apart and confirming they're silver comes down to a few quick checks. Unlike silverware, coins rarely carry a separate hallmark — the date, Ley marking, and design do the work instead. Mexican and British coins announce themselves very differently.

• Mexican coins — read the "Ley": look for "Ley .720," "Ley .900," or ".925 Plata" near the edge or date. That number IS the purity. No Ley marking and dated after 1977? Almost certainly no silver.
• British coins — read the date: 1919 or earlier = sterling; 1920–1946 = 50% silver; 1947 or later = no silver. The date is your purity guide.
• Check the language & design: Mexican coins read in Spanish with the national eagle-and-serpent; British coins show a monarch's profile and English/Latin legends.
• Magnet test both: real silver is non-magnetic. If a strong magnet grabs the coin, it's base metal — common in post-cutoff issues.
• Weigh to confirm: a 0.1g scale plus the date/Ley gives you everything a calculator needs. Worn coins lose a little weight, lowering melt slightly.

For US coins, the same date-based logic applies but with different cutoffs — our silver coin value calculator guide covers American denominations, and the Canadian silver guide handles Canada's .800 and .500 transitions.

Frequently Asked Questions

Conclusion: Date First, Then Multiply

Mexican and British silver coins follow opposite rules but reach the same answer. Mexico stamps the purity on the coin — read the "Ley." Britain leaves it to the date — 1919 and earlier is sterling, 1920–46 is half silver, 1947 on is base metal. Once you know the purity, every coin's value is just its silver weight times the spot price.

To turn your specific coins into live numbers, use the calculator below — pick the coin, confirm the purity from its date or Ley marking, and see exactly what your Mexican and British silver is worth right now, in any currency.