Guide

Why Is US Money Green? The Colour Code of the World's Banknotes

American money is green because of a camera. In 1861 the only way to photograph a banknote was in black and white, so printing the back in green defeated the copier. What is stranger is why it stayed green for the next 160 years, long after photography stopped being the threat. The Bureau of Engraving and Printing's own answer is refreshingly plain.

Green since 1861 Series 1928 standardized it Colors returned in 2003 17 denominations charted

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Last updated: September 2026

Why is US money green?

Because of the camera. The Bureau of Engraving and Printing states that the backs of the 1861 Demand Notes were printed with green ink and that "it is believed that the green ink was meant as a deterrent to counterfeiters who would have used photography as a means of reproduction." The early camera saw only black and white.

The mechanism is worth understanding precisely, because most retellings get it backwards. It was not that green photographed badly. It was that colored features lost their individuality when reproduced photographically, so a note whose security detail lived in the color survived the copying process as an obvious fake (Bureau of Engraving and Printing, Currency Notes). The Federal Reserve Bank of San Francisco puts the naming plainly: the term greenback for United States paper money originated with the Demand Notes of 1861, and their green reverses are the origin of the word (FRBSF).

Our page on greenbacks and Legal Tender Notes covers the Civil War financing that produced those notes, the acts of 1861 and 1862, and the Supreme Court fights that followed. This page picks up where that one leaves off: what happened to the color after the crisis passed.

What changed with Series 1928?

Series 1928 shrank American money and standardized it. The notes were made about 30 percent smaller, measuring 6.14 by 2.61 inches instead of 7.375 by 3.125 inches, and each denomination got one fixed design instead of many competing ones.

The stated motive was cost, not beauty. Smaller notes meant more notes per sheet and less paper per dollar printed. The side effect mattered more: with a single standardized design per denomination, the number of designs in circulation collapsed, which made it far easier for an ordinary person to tell a genuine note from a counterfeit (uscurrency.gov). Before that change, a cashier in 1920 might plausibly see dozens of legitimate designs for the same value.

Color did the same job. With the introduction of Series 1928, the large-size notes were reduced to their present size and green Treasury seals were overprinted on all denominations of Federal Reserve Note, while other classes of currency received seals in their own colors. The small-size notes reached the public in 1929, and the shape and palette of American money have barely moved since.

Why did the Treasury keep green after 1929?

Habit, essentially. The Bureau of Engraving and Printing writes that "with the introduction of Series 1928, the use of green was continued, most likely because of the strong tradition of using green color on U.S. currency."

There is a practical footnote. By 1929 the green was doing a different job from the one it had in 1861. It had become an identifier: green ink and a green seal meant a Federal Reserve Note, and a different seal color meant something else entirely. Changing it would have thrown away sixty years of public recognition to solve a problem that the camera no longer posed.

When did US money stop being only green?

In 2003, when the redesigned twenty dollar note arrived with subtle background colors of green and peach. Four more denominations followed by 2013, and the one and two dollar notes were left alone.

The sequence, all from the Federal Reserve's currency education program, is exact. The twenty came first in 2003 with green and peach backgrounds and a color-shifting numeral 20. The fifty followed in 2004 with blue and red. The ten arrived in 2006 with orange, yellow and red. The five came in 2008 with light purple and gray. The hundred was last, in 2013, in its first redesign since 1996, gaining a 3-D Security Ribbon and a color-shifting Bell in the Inkwell (uscurrency.gov).

Note what this is not. The United States still does not color-code its denominations the way the euro or the pound does. The background tints are subtle, the notes are all the same size, and the overall impression of a fistful of American cash is still green. That is a deliberate choice about continuity rather than a failure of design, and it is the single biggest difference between US currency and almost every other major currency in the world. Our guide to the banknote design process covers how those decisions get made.

What color is each denomination?

The table below charts 17 denominations across three currencies, with the dominant color and the date it took effect, each row taken from the issuing authority rather than from a photograph.

US rows from uscurrency.gov and the BEP booklet Currency Notes. Sterling rows are the dominant colors the Bank of England publishes for each of those four notes on its withdrawn banknotes page, with the period each was in force; the Bank publishes no color description for the polymer notes that replaced them, and currently issues four denominations, £5, £10, £20 and £50 (Bank of England). Peso rows and circulation dates from Banco de México.

What do the seal colors on old US notes mean?

On small-size notes from Series 1928 onward the seal color tells you the class of currency: green for a Federal Reserve Note, blue for a Silver Certificate, red for a United States Note, orange for a Gold Certificate and brown for National Bank Notes and Federal Reserve Bank Notes.

Before Series 1928 there was no such logic. The BEP records that between 1862 and 1929 the color and style of the Treasury seal varied greatly from issue to issue, and that a single issue could carry several. The Series 1886 five dollar Silver Certificate alone was issued with small plain red seals, small scalloped red seals, large red seals and large brown seals, and the Bureau notes that no documentation has been found explaining why certain seals went on certain notes.

Wartime pushed the code further. Between 1942 and 1944, Silver Certificates and Federal Reserve Notes overprinted "Hawaii" circulated only in Hawaii, and their brown seals and serial numbers set them apart from mainland notes so they could be repudiated if the islands were overrun. Silver Certificates issued for the North Africa invasion in November 1942 carried distinctive yellow Treasury seals for the same reason, against the blue seals of regular Silver Certificates. For a collector, seal color is the fastest way to sort a mixed group of small-size US notes.

Why do other countries color-code their denominations?

Because color is the fastest identification cue a note has, and because a currency where every denomination looks alike is harder to use for anyone with low vision.

The South African Reserve Bank states the principle in one line: South African banknotes "can be differentiated from one another by considering the dominant colour, animal theme and size" (South African Reserve Bank). Three cues, working together, so that losing one does not leave you stranded. Mexico applies the same idea, giving every G type denomination its own stated predominant color, from the purple 50 to the gray 1,000.

Australia took the logic a step further. The Next Generation series pairs distinct denomination colors with a raised tactile feature so that people who are blind or have low vision can tell the notes apart by touch, alongside a different native bird and wattle on each value (Reserve Bank of Australia). The United States, with seven same-size denominations in broadly the same color, is the outlier among major currencies, which is exactly why the 2003 to 2013 background tints were introduced.

Is color a security feature?

Yes, in three distinct ways: color that shifts when you tilt the note, color that only appears under ultraviolet light, and color that a copier cannot reproduce faithfully.

The first is the color-shifting numeral in the lower right corner of the redesigned US twenty, fifty and ten dollar notes, and the color-shifting Bell in the Inkwell on the hundred. The second is the embedded security thread, which glows a different color for each denomination: green on the twenty, yellow on the fifty, orange on the ten and blue on the five (uscurrency.gov). Learn the thread colors and you can check four denominations under one lamp.

The Bank of England uses the same trick in foil rather than ink. The metallic image over the see-through window is gold on the front of the £5 and £10 notes, gold and blue on the £20 and gold and green on the £50, so the foil color itself confirms the denomination (Bank of England). The third use is the oldest one on this page, the 1861 idea that a color a copier cannot match is a defense in itself, and it survives in the optically variable inks on modern notes. Our guide to banknote security features walks through the full list, and if you want the American story from the Civil War forward, start with greenbacks and Legal Tender Notes or browse the US banknotes collection.

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