Date Codes
Every Zippo windproof lighter made since the mid-1950s carries a date code stamped into the base. Originally a quality-control tool for founder George G. Blaisdell, it has since become the standard way to date the collection. This page collects the chart for every era in one place.
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Letter + two-digit year
Since 2001 the date code has been a single letter (month) followed by the last two digits of the year. The 12 month letters run A through L.
Zippo regular lighter identification codes
Official year-by-year stamp reference for the standard (regular) Zippo windproof lighter. Each row shows the mark variant stamped onto the base for that year.
Zippo Slim® lighter identification codes
Slim-body Zippos follow a parallel but distinct code system. The chart below gives the canonical year-by-year reference for the Slim line.
Code systems by era
Seven code systems have been in use across Zippo's history. Bottom-stamp markings change roughly every decade. The era table below is the quick key; the official Zippo charts above show the exact stamp for each year.
- 1933 – 1957
No date code
No stamped date code. Lighters are attributed by style, model, and patent marking ("PAT. PENDING", "PAT. 2032695", "PAT. 2517191") in combination with the block-letter Zippo logo.
PAT. PENDINGPAT. 2032695PAT. 2517191
- 1958 – 1965
Patent number + pattern of dots
Bottom stamp reads "PAT. 2517191" with a pattern of dots flanking the word ZIPPO. Dot count decreases each year through the 1960s.
- 1966 – 1973
Dots (pat. pending retired)
Patent number drops off. Dots continue as the year indicator — four dots on each side in 1966, counting down to zero by 1973.
- 1974 – 1981
Forward slashes
Dots are replaced by forward slashes on each flank. Four slashes per side in 1974 decreasing to zero in 1981.
- 1982 – 1985
Backslashes
Slashes reverse direction. Four backslashes per side in 1982 decreasing to one in 1985.
- 1986 – 2000
Roman numerals + letter month
The modern system begins. A Roman numeral encodes the year (II = 1986 through XVI = 2000) and a leading letter A–L gives the month of manufacture.
- 2001 – present
Letter month + two-digit year
Current system. A letter A–L identifies the month, followed by the last two digits of the year. Example: K 25 = November 2025.
The historic Zippo logos
Before reading the code itself, the shape of the word Zippo on the bottom narrows the era. Three major logo revisions: block letters from 1933 through the mid-'50s, the script logo phased in around 1955, and the redesigned script introduced in 1980.
