/ˈrɛkənər/
[noun] A person who calculates or counts things, or a book or table that helps people do calculations quickly and easily. The word can also describe someone who makes judgements or assessments.
Before calculators existed, a 'ready reckoner' was a pocket book of pre-calculated answers — the medieval equivalent of a smartphone app.
The story of 'reckoner' begins in the dark, practical heart of Old English, where the verb 'recenian' or 'gerecenian' meant to arrange, explain, or give an account of something. This was a word rooted in the daily business of life — counting livestock, settling debts, reporting to a lord. It shares its ancestry with the Proto-Germanic root '*rekon-', which carried the sense of arranging things in order, making them straight and clear. The same root gave rise to Old High German 'rehhanon' and Old Norse 'reikna', both meaning to count or calculate, showing how deeply this idea of careful numbering was woven into the Germanic-speaking world.
From the Old English 'recenian', the language evolved through the Middle English period into the form 'rekenen', meaning to count, calculate, or narrate. This is the same journey taken by its close Dutch cousin 'rekenen' and German 'rechnen', both of which still mean 'to calculate' today. What is striking about this family of words is how naturally the idea of counting slipped into the idea of explaining — to give an account of numbers was also to give an account of events, which is why 'reckon' in English eventually stretched to mean 'to think' or 'to suppose', as when someone says 'I reckon it will rain.'
The suffix '-er', added to 'reckon', follows one of the oldest and most productive patterns in English: attach '-er' to a verb and you create a noun describing a person who does that thing. So a 'reckoner' was, at its most basic, a person who reckoned — someone who counted grain, tallied wages, or kept accounts. In the Middle Ages, this was a highly valued skill. Merchants, tax collectors, and stewards of great estates all needed people who could reckon accurately, and the word carried real professional weight.
By the 16th and 17th centuries, 'reckoner' had expanded beyond people to describe objects. A 'reckoner' could be a counting table or a set of mathematical aids — precursors to printed calculation guides. The phrase 'ready reckoner' became common by the 18th century, referring to printed books of pre-calculated tables covering interest, wages, weights, and measurements. These were enormously popular tools for tradespeople, allowing anyone to look up an answer rather than work through the arithmetic themselves. They were, in their time, as transformative as the spreadsheet would later be.
The cultural reach of the word is perhaps best illustrated by its appearance in popular art. Nick Cave and the Bad Seeds released the album 'The Good Son' in 1990, and earlier the band's 1988 album was titled 'Tender Prey', but it is the phrase 'the day of reckoning' that has cemented the word most powerfully in the English imagination. This phrase — meaning a moment when past actions are finally judged and their consequences faced — draws directly on the theological sense of reckoning as a final divine account. On Judgement Day, all debts would be counted. The word thus carries within it centuries of commercial, mathematical, and spiritual meaning, all braided together from that single Old English root of making things clear and straight.