Converter evidence
Five converters remain dimensionally separate. Length resolves through metres, Weight through grams, Time through seconds, Liquid through litres, and Area through square metres.
Length converter
42 standards
Base: metre. Records retain period, region, basis, confidence, and uncertainty.
Weight converter
42 standards
Base: gram. Records retain period, region, basis, confidence, and uncertainty.
Time converter
26 standards
Base: second. Records retain period, region, basis, confidence, and uncertainty.
Liquid converter
58 standards
Base: litre. Records retain period, region, basis, confidence, and uncertainty.
Area converter
21 standards
Base: square-metre. Records retain period, region, basis, confidence, and uncertainty.
Converter source register
This list is generated from the matrices. Counts show direct record use; they do not imply that one source proves every use of a named measure.
- Ancient Mesopotamian units overview
Time: 4 records. Mesopotamian geš, Mesopotamian watch, Mesopotamian schematic month and more. - Archaeological Survey of India observatory guide
Time: 4 records. Indian vipala, Indian vinadi or pala, Indian ghati and more. - Archive for History of Exact Sciences 2025
Length: 1 record. Attic stadion. - Australian National Measurement Institute
Liquid: 3 records. Australian spirit measure (15 mL), Australian spirit nip (30 mL), Australian spirit measure (60 mL). - BIPM SI Brochure
Length: 3 records; Weight: 5 records; Time: 5 records; Liquid: 3 records. metre, centimetre, millimetre and more. - BIPM historical overview
Length: 1 record. Egyptian khet. - British Museum EA23078
Length: 2 records. Egyptian royal cubit (New Kingdom rod), Egyptian palm. - British Museum Mesopotamian weight
Weight: 4 records. Mesopotamian grain, Mesopotamian shekel, Mesopotamian mina and more. - British Weights and Measures in the Laws of England
Weight: 1 record. Tower pound (medieval English representative). - Buildings 2025 Angkor Wat geometric planning review
Length: 1 record. Khmer hat (Angkor Wat reconstruction). - Cambridge Early China metrology study
Weight: 2 records. Qin-Han liang, Qin-Han jin. - Digital Egypt and metrological literature
Length: 1 record. Egyptian short cubit. - Encyclopaedia Iranica, weights and measures
Weight: 3 records. Achaemenid shekel standard, Achaemenid karsha, Achaemenid-Babylonian talent. - GOV.UK specified alcohol quantities
Liquid: 10 records. UK still-wine glass (125 mL), UK still-wine glass (175 mL), UK spirit measure (25 mL) and more. - Indian National Science Academy, weighing devices
Weight: 4 records. Mauryan ratti, Mauryan masha, Mauryan purana or dharana and more. - Journal of Roman Archaeology
Liquid: 1 record. Roman sextarius. - NIST Handbook 44 Appendix C
Liquid: 2 records; Area: 5 records. US liquid gallon, US liquid pint, square metre and more. - NIST Handbook 44 Appendix C
Length: 4 records. inch, international foot, yard and more. - NIST SI units: mass
Weight: 7 records. avoirdupois grain, troy grain, pennyweight and more. - Nature 144 360
Length: 1 record. Olympic stadion. - Petrie The Pyramids and Temples of Gizeh
Length: 2 records. Egyptian royal cubit (Giza), Egyptian digit. - Queensland Health alcohol guide
Liquid: 5 records. Australian standard wine glass (100 mL), Australian restaurant wine glass (150 mL), Australian pot or middy (285 mL) and more. - Smith Dictionary Hora
Time: 2 records. Greek equinoctial hour, Roman equinoctial hour. - Smith Dictionary Hora and calendar reference
Time: 1 record. Roman nundinal cycle. - Smith Dictionary Mensura
Length: 9 records; Liquid: 10 records; Area: 6 records. Roman pes, Roman cubitus, Roman passus and more. - Smith Dictionary Pes
Length: 3 records. Roman digit, Roman uncia, Roman palmus. - Smith Dictionary Pondera
Weight: 11 records. Attic obol, Attic drachma (mass), Attic mina and more. - Smithsonian Living Maya Time
Time: 5 records. Maya k'in, Maya uinal, Maya tun and more. - Stone 2014 Cubit history
Length: 3 records. Nippur cubit, Mesopotamian digit, Mesopotamian nindan. - Thom 1977 The Megalithic Yard
Length: 1 record. Megalithic yard (Thom hypothesis). - UCL Digital Egypt area measures
Area: 3 records. Egyptian land-unit (ta), Egyptian thousand (kha), Egyptian setjat (aroura). - UCL Digital Egypt volume measures
Liquid: 2 records. Egyptian hin, Egyptian heqat. - UCL Digital Egypt, area
Area: 7 records. Egyptian sa (Old Kingdom), Egyptian heseb (Old Kingdom), Egyptian remen area (Old Kingdom) and more. - UCL Digital Egypt, calendar
Time: 5 records. Egyptian civil day, Egyptian ten-day period, Egyptian civil month and more. - UCL Digital Egypt, length
Length: 10 records. Egyptian hand, Egyptian fist, Egyptian double handbreadth and more. - UCL Digital Egypt, volume
Liquid: 7 records. Egyptian ro, Egyptian dja, Egyptian double heqat and more. - UCL Digital Egypt, weight
Weight: 5 records. Egyptian deben (Old and Middle Kingdom), Egyptian shematy (Old and Middle Kingdom), Egyptian qedet (New Kingdom) and more. - UK Weights and Measures Act 1985
Liquid: 2 records. imperial gallon, imperial pint. - US Alcohol and Tobacco Tax and Trade Bureau
Liquid: 1 record. US beer barrel (31 US gallons). - US Government historical British cask table
Liquid: 5 records. British beer pin (4.5 imperial gallons), British beer firkin (9 imperial gallons), British beer kilderkin (18 imperial gallons) and more. - US Government historical measure table
Liquid: 7 records. English wine rundlet (18 wine gallons), English wine barrel (31.5 wine gallons), English wine tierce (42 wine gallons) and more.
Coverage audit and research boundary
The audit began with the Ancient Egyptian overview and its linked Mesopotamian, Hebrew, Persian, Greek, and Roman measurement pages, then checked museum, academic, government, and specialist references. Egypt, Mesopotamia, Greece, Rome, Persia, early imperial China, ancient India, and the Classic Maya now have representation where a defensible fixed magnitude was available.
Not “every ancient unit.” No finite converter can honestly claim that. Local standards, commodity-specific systems, chronological reforms, uncertain Hebrew and Levantine correspondences, variable seasonal hours, and calendar-date correlations are withheld until a specific corpus and chronology can be named.
Geometry, artefact, and site sources
- British Museum, Rhind Mathematical Papyrus problem 56 explainer
Pyramid mathematics and seked. - British Museum, Romano-British dodecahedron 1924,0411.1
Object dimensions and aperture range. - English Heritage, Roman dodecahedra
Archaeological status and unresolved function. - Wolfram MathWorld, Regular Dodecahedron
Ideal-solid formula verification. - UNESCO, Memphis and its Necropolis
Giza heritage context. - UNESCO, Ancient Thebes with its Necropolis
Karnak heritage context. - UNESCO, Acropolis of Athens
Parthenon heritage context. - Oxford Academic, Parthenon dimensions
Parthenon stylobate dimensions. - Digital Karnak, Hypostyle Hall
Karnak hall plan, column count, and central height. - British Institute for the Study of Iraq, Ur guide
Ziggurat lower-platform dimensions and cubit model. - Perseus Art and Archaeology, Temple of Aphaia
Aphaia stylobate and column plan. - Smarthistory, The Pergamon Altar
Great Altar footprint. - UNESCO, Archaeological Site of Olympia
Olympia heritage context. - Greek Ministry of Culture, Temple of Aphaia
Aphaia temple context. - UNESCO, Pergamon and its Multi-Layered Cultural Landscape
Pergamon architecture, terrain, and engineering. - Italian Ministry of Culture, Pantheon
Pantheon interior diameter and equal height. - Penn Museum, The Ziggurat of Ur
Ur excavation dimensions and reconstruction. - English Heritage, Understanding Stonehenge
Stonehenge solstitial geometry and evidence limits. - UNESCO, Angkor
Angkor Wat heritage, landscape, and symbolic context. - Buildings 2025, Angkor Wat geometric planning review
Khmer hat reconstruction and its limitations. - Alexander Thom, The Megalithic Yard
Original statistical unit hypothesis. - Journal of the Royal Statistical Society, Bayesian Analysis of the Megalithic Yard
Statistical critique and regional concentration. - Mathematical Association of America, Eratosthenes and the Mystery of the Stades
Alexandria to Syene baseline and stadion problem. - Oxford Academic, Eratosthenes and the Measurement of the Earth’s Circumference
Historical framing of Eratosthenes’ method.
Local research library added 13 July 2026
Seven searchable books in the project data folder were audited across 1,631 PDF pages. They are research evidence, not downloadable site assets. Page-level candidates were checked against rendered pages before they influenced the present release.
- Ronald Edward Zupko, A Dictionary of Weights and Measures for the British Isles: The Middle Ages to the Twentieth Century (1985).
Regional and chronological disambiguation for British units; particularly useful for names that changed by market, commodity, or locality. - British Weights and Measures as Described in the Laws of England from Anglo-Saxon Times.
Money pounds, troy relationships, medieval pennies, grain definitions, and the distinction among contemporary pounds. - Sir Flinders Petrie, Ancient Weights and Measures (1926).
Artefact-led Egyptian and eastern Mediterranean weight systems; includes explicit cautions about corrosion, wear, cleaning, and coinage-driven change. - John Arbuthnot, Tables of Ancient Coins, Weights and Measures, historical edition.
Early comparative coin tables, troy-grain measurements, English sterling and gold-coin fineness, and useful evidence about the history of measurement claims. Older conclusions require modern corroboration. - John Arbuthnot, Tables of the Grecian, Roman and Jewish Measures, Weights and Coins (1705 excerpt).
Compact historical table retained as comparative evidence, not as the sole authority for a modern magnitude. - Arthur S. C. Wurtele, Standard Measures of the United States, Great Britain, and France (1882).
History and physical comparison of modern national standards during metric transition. - P. H. Felker, The Grocers' Manual (1878).
Commodity-specific commercial measures and nineteenth-century conversion tables; particularly useful for showing why trade units cannot be merged by name alone.
Immediate inclusion boundary. Troy units, metric carat mass, and a dated Tower pound representative meet the present data threshold. Generic mark, ell, stone, bushel, gallon, and commodity pounds remain deferred until each record can name its jurisdiction, commodity, period, and source basis.
How sources are used
A linked source supports the category of claim named in its note. Defined modern values, reconstructed ancient standards, named serving capacities, historical cask schedules, artefact records, and interpretive claims are different evidence classes. The site does not promote one class into another.
Where a source gives a relationship rather than a direct modern magnitude, the matrix records that relationship as its basis. A historical vessel name is not assumed to equal every surviving object bearing that name, and a published serving volume is not treated as a measure of alcohol content.
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