Historical Unit & Currency Converter

What this tool does

Pick a category, choose any unit as the source, type a value and choose any unit as the target. The tool computes the conversion through the category's SI base (metres, square metres, kilograms or litres) for physical units, and through the smallest denomination (pies, dams, quadrans, chalci) for currencies. Below the result you see a notes panel describing where each unit comes from and a complete conversion table — "1 [from] = X [each other unit]" — so you can scan the whole family of units at once. Every value, conversion and table can be copied as CSV, downloaded as JSON or printed.

What's included

Length / Distance (24 units)

Indian: angula, vitasti, hasta (cubit), dhanus / danda, kos / krosa, yojana. Imperial: inch, foot, yard, fathom, rod / perch, Gunter\'s chain, furlong, statute mile, nautical mile, English league. Roman: pes (Roman foot), passus (pace), mille passus (Roman mile). Greek / Persian / Egyptian: pous (Greek foot), stadion, parasang, royal cubit. Modern: metre, kilometre.

Area (15 units)

Indian: marla, kanal, biswa (Bengal), katha (Bengal), bigha (Bengal pakka, UP pakka, Rajasthan). Imperial / metric: square foot, square yard / gaz, are, acre, hectare. Roman / Egyptian: iugerum, aroura, feddan.

Weight / Mass (26 units)

Indian (Mughal-British, codified 1833): ratti (krishnala), masha, tola, chhatak, pao / pav, seer, maund. Ancient Indian: karsha, pala. Imperial: grain, ounce (avoirdupois), troy ounce, pound, stone, hundredweight (long), long ton. Roman: libra, uncia, Roman talent. Greek: Attic drachma, mina, talent. Egyptian: deben. Metric: gram, kilogram, tonne.

Volume / Capacity (17 units)

Indian: kuduva, prastha, adhaka, drona. Imperial: fluid ounce, pint, quart, gallon (UK and US), bushel. Roman: sextarius, congius, amphora, modius. Greek: choes, metretes. Metric: millilitre, litre.

Currency systems (4)

• Pre-decimal Indian / British rupee — pie, pice / paisa, anna, silver rupee, mohur, sovereign. 1 rupee = 16 anna = 64 pice = 192 pies.
• Mughal trimetallic system (Akbar standard, 1556–1605) — copper dam, half-rupee, silver rupee, gold mohur. 40 dam = 1 rupee; 1 mohur ≈ 10 rupees.
• Roman currency (Augustan / early imperial) — quadrans, as, dupondius, sestertius, denarius, aureus. 1 aureus = 25 denarii = 100 sestertii = 400 asses = 1,600 quadrans.
• Attic Greek — chalcus, obol, drachma, tetradrachm, mina, talent. 1 talent = 60 minas = 6,000 drachmas = 36,000 obols = 288,000 chalci.

Worked examples

1 yojana = ? Set Category to "Length / Distance", From to "Yojana", Value to 1, To to "Mile". Result: 1 yojana ≈ 8.0 miles (using 4 krosas × 3.219 km). The notes panel reminds you that some texts use 8 krosas instead of 4, in which case yojana ≈ 16 miles.

1 maund = ? Length category → Weight / Mass → From "Maund" → To "Pound". Result: 1 maund = 82.286 lb (40 seers × 0.93310 kg = 37.3242 kg). The same maund equals 80 lb troy or 17,920 tolas.

1 acre = ? Area → From "Acre" → To "Bigha (Bengal pakka)". Result: 1 acre ≈ 3.025 Bengal pakka bighas. Switch the bigha to UP pakka and the answer changes to about 1.613 — a useful demonstration of why "bigha" alone is ambiguous.

1 mohur = ? rupees. Currency → Pre-Decimal British / Indian rupee → From "Mohur" → To "Rupee (silver)". Result: 1 mohur = 15 rupees, the value the British codified in 1835. Switch to "Anna" and you get 240 anna; switch to "Pie" and you get 2,880 pies.

1 talent = ? Currency → Attic Greek → From "Talent" → To "Drachma". Result: 1 talent = 6,000 drachmas. Switch the To unit to "Obol" and you get 36,000 obols. (As weight, 1 Attic talent ≈ 25.86 kg of silver.)

Why historical units matter for history study

Ancient and medieval texts measure the world in units that were normal then but are unfamiliar today. The Arthashastra describes troop sizes in vyuhas, distances in yojanas and crops in dronas. The Akbarnama records imperial revenues in dams and rupees. Roman histories cost-out a soldier\'s yearly pay in denarii. Greek inscriptions list temple offerings in talents. To read those sources without converting is to read them only loosely. A working sense of the magnitudes — that 1 yojana is roughly a long day\'s march, that 1 talent of silver was a fortune by any age\'s standards, that 1 acre is enough land for a household but 1 maund is a wholesale weight — turns the texts from numbers into life.

For UPSC, SSC and State PSC syllabi, the Indian units are standard exam material: bigha, kanal, marla, tola, seer, maund, kos and yojana appear in the medieval and modern Indian history papers. Roman and Greek units appear in world history papers. The 1 rupee = 16 anna ratio is a recurring multiple-choice topic.

Why ancient values are approximate

Modern units like the metre, second, kilogram and yard have rigid, standardised definitions. Ancient units rarely did. A "kos" in Akbar\'s revenue records is longer than a "kos" in the Arthashastra. A Bengal "pakka" bigha is different from a Bengal "kachcha" bigha; both differ again in Uttar Pradesh and Rajasthan. The Greek "stadion" varied by city; the Roman foot was 0.296 m, the Greek foot 0.308 m, the Egyptian royal cubit 0.524 m. The factors in this tool are widely cited averages — useful for quick orientation but not for legal or scholarly precision. Use the notes panel beneath the result to see which value applies, and overwrite if your textbook quotes a different one.

How to use the tool

1. Pick a Category from the dropdown — physical (length, area, weight, volume) or currency (British India, Mughal, Roman, Greek).
2. Type a Value.
3. Pick the From unit (the one you have).
4. Pick the To unit (the one you want).
5. Read the main result and the via base unit figure beneath it.
6. Use Swap From / To to reverse the direction with a single click.
7. Scan the table — "1 [from] = X each other unit" — to see the whole family of units at a glance.
8. Print, Copy CSV, or Download JSON from the action bar to save your conversion.

FAQs

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