ready reckoner

Noun

ready reckoner (plural ready reckoners)

1. (historical) A printed book or table containing precalculated values, often multiples of given amounts.
   • Nor did he trouble his borrowers with abstract calculations of figures, or references to ready-reckoners; his simple rule of interest being all comprised in the one golden sentence, ‘two-pence for every half-penny,’ which greatly simplified the accounts[…]1838 March – 1839 October, Charles Dickens, chapter 1, in The Life and Adventures of Nicholas Nickleby, London: Chapman and Hall, […], published 1839, →OCLC
   • Instead of allowing the peasants to manage their own affairs, and, if they happen to believe that five and four make eleven, to unlearn the prejudice by their own experience in calculation, so that they may gradually understand processes, and not merely see results, bureaucracy comes with its...1883, George Eliot, “Natural History of German Life”, in Nathan Sheppard, editor, The Essays of George Eliot
2. A computer program which calculates values; an online calculator.