Historical Unit & Currency Converter
85+ historical units in 8 categories — kos, yojana, tola, seer, maund, bigha, kanal, marla, libra, mina, talent, drachma, denarius, anna, rupee, mohur and more — with full regional notes for every unit.
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
- Pick a Category from the dropdown — physical (length, area, weight, volume) or currency (British India, Mughal, Roman, Greek).
- Type a Value.
- Pick the From unit (the one you have).
- Pick the To unit (the one you want).
- Read the main result and the via base unit figure beneath it.
- Use Swap From / To to reverse the direction with a single click.
- Scan the table — "1 [from] = X each other unit" — to see the whole family of units at a glance.
- Print, Copy CSV, or Download JSON from the action bar to save your conversion.
FAQs
How many kilometers is one yojana?
A yojana does not have one fixed kilometer value for every period and text. In many study contexts, it is treated roughly as 12 to 15 kilometers, though some traditions use smaller or larger values. That is why you should not convert it like a modern metric unit. If a question gives a specific standard, use that standard. If not, write "approximately" and mention that the value varied by text, region, and period. For history, the variation is more important than false precision.
How many miles is one kos?
One kos, also called krosa in some texts, is usually treated as roughly 2 miles, or about 3 to 3.2 kilometers, in many traditional explanations. But like yojana, it was not a perfectly fixed modern unit. Its value could vary by region and period. In Mughal and early modern contexts, kos markers were used along roads, which shows its practical importance for distance. For exams, write the approximate value only if needed, and add that historical units were not always standardized.
How much is one maund in kilograms?
One maund is commonly taken as 40 seers in the British Indian standard, which is about 37.3 kilograms. However, older regional standards could vary, so the exact value depends on place and period. This is why historians are careful when converting grain, revenue, or trade quantities from old records. For quick study, remember: 1 maund = 40 seers = about 37 kilograms in the common colonial standard. If the source belongs to a specific region, check its local weight system. Use approximate conversions unless the source gives a fixed standard.
How many annas were in one rupee?
There were 16 annas in one rupee in the old Indian currency system. One anna was further divided into 4 pice, and one pice into 3 pies. So, 1 rupee = 16 annas = 64 pice = 192 pies. This system was used before decimalization, when India moved to 100 paise in a rupee. For history questions, the important point is that anna belongs to the pre-decimal currency system. Do not mix it with modern paise calculations. For historical units, the word 'about' is often more honest than false precision.
What was a Mughal dam worth in rupees?
A Mughal dam is usually explained with the study ratio of 40 dams to 1 rupee. So, 1 dam was 1/40 of a rupee in that accounting sense. It should not be treated like a modern exchange rate, because coin values depended on metal, weight, ruler, and period. For exam purposes, the useful line is: in the Mughal monetary system, 40 dams made one rupee. This helps when reading revenue references, price lists, or administrative details from the period. Use approximate conversions unless the source gives a fixed standard.
How do I convert Roman denarius to sestertius?
In the common early imperial Roman system, 1 denarius was equal to 4 sestertii. So if you have 10 denarii, you multiply by 4 and get 40 sestertii. The denarius was a silver coin, while the sestertius was often used as an accounting and bronze coin unit. Like all ancient currency, values could shift over time, but this 1:4 ratio is the usual classroom conversion. For quick revision, remember: denarius to sestertius means multiply by 4. For historical units, the word 'about' is often more honest than false precision. Source notes for current-reference facts The attached spreadsheet was used as the main source for the questions and suggested response angles. For current-reference points, especially India's states, union territories, capitals, and the present prime minister sequence, official Government of India pages were checked. National Portal of India / Know India - States and Union Territories: https://knowindia.india.gov.in/states-uts/ Prime Minister of India official website - PM profile: https://www.pmindia.gov.in/en/ Prime Minister of India official website - Former Prime Ministers: https://www.pmindia.gov.in/en/former-prime-ministers/ Historical facts are phrased for classroom and exam revision. Where a historical unit or ancient boundary varies by period or region, the response says so rather than giving false precision.