Does The Historian's Knife work offline?
Yes. The Historian's Knife is a single HTML file that runs entirely in your browser. No internet connection required after download. Your data never leaves your device.
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The Historian's Knife
Calendar systems, numerals, and genealogy tools — offline, forever
The Weird & WonderfulKnife 31 of 50
$39
One-time purchase · Instant download30-day money-back guarantee
$39
What it does
The Historian's Knife puts five essential history and genealogy tools into a single HTML file. Convert dates between Gregorian, Julian, Hebrew, and Islamic calendars with Julian Day Numbers, convert Roman numerals in both directions with full reference tables, explore ancient numeral systems including Babylonian, Egyptian, and Mayan, look up regnal years for English and French monarchs, and compute Soundex codes for genealogical name matching — all offline, all private, all yours forever.
LIVE DEMO — TRY IT NOW
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INCLUDED TOOLS — 5 TOTAL
\Calendar Converter (Gregorian/Julian/Hebrew/Islamic)
\Roman Numeral Converter
\Ancient Numeral Systems
\Regnal Year Calculator
\Genealogy Soundex
USE CASE 01\Fall of Constantinople
USE CASE 02\Norman Conquest
USE CASE 03\American Independence
USER'S GUIDE
Download PDFFull documentation with detailed instructions for every tool.
DELIVERYSingle HTML fileDownload instantly after purchase
PRIVACY100% localYour data never leaves your machine
OWNERSHIPOne-time purchaseNo subscription, no recurring fees
PRO TIP
The file works in any modern browser — Chrome, Firefox, Safari, Edge. Save it to a USB drive, email it to yourself, or keep it in your cloud storage. It will work anywhere, anytime, forever.
Sovereignty as a Service
$39. Yours. Forever.
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OTHER PRODUCTSIs The Historian's Knife a subscription?
No. The Historian's Knife is a one-time purchase of $39. No monthly fees, no renewals, no price increases.
What is included in The Historian's Knife?
The Historian's Knife bundles 5 the weird & wonderful tools into a single HTML file: Calendar Converter (Gregorian/Julian/Hebrew/Islamic), Roman Numeral Converter, Ancient Numeral Systems, Regnal Year Calculator, Genealogy Soundex.
Where is my data stored?
Entirely in your browser's local storage. Nothing is uploaded, transmitted, or tracked. You can export your data as JSON at any time and import it on another device.
Which browsers and operating systems does The Historian's Knife support?
Any modern browser — Chrome, Firefox, Safari, Edge — on Windows, macOS, Linux, ChromeOS, iOS, or Android. The same file works everywhere.
Can I try The Historian's Knife before buying?
Yes. The interactive demo on this page is the full knife running in an iframe. Try every feature in your browser, no signup required.
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