International Slide Rule Museum (ISRM)

ISRM is the world's largest free digital repository of all things concerning slide rules and other math artifacts.
As of 2023, ISRM is celebrating its 20th Anniversary!

ISRM is an IRS 501(c)(3) (A57 - Science and Technology Museums) non-profit corporation through the State of Colorado. Colorado ID Number 20181884948, IRS EIN 83-2486423. - ISRM Advisory Board of Directors.

Donations are
tax deductable
2022 was the 400th anniversary of the slide rule as described by Willaim Oughtred.
2022 was also the 50th anniversary of the HP-35 Electronic Slide Rule Calculator.

Visit What's New! for the latest additions to the galleries and changes to the website.
ISRM is best viewed on a desktop. Clear your browser cache often CTRL+F5

or Press
Post and Chat on ISRM @sliderulemuseum and Instagram page

Click on the above Slide Rule for the Introduction, ISRM Mission Statement, and Donation Policies.

A Historical Slide Rule Timeline in Pictures

1550-1617 John Napier Invented the Logarithm in 1614
1574-1660 William Oughtred Inventor of the Slide Rule

1831-1906 Victor Amédée Mannheim standardized modern scales

c1890 DUPA (Aristo) Class Germany

c1900 Englewood (NY) High School Students

c1905 IIT Classroom

1909 IIT Elect. Engineers

1934 Iowa State SR Class

1941 IIT Engineering

1942 Purdue Aeronautics

1950 Students Prarie View, TX. Texas A&M

1952 Edwards AFB
Test Pilot School

1954 Hamburg, Germany

1956 Edwards AFB
Test Pilot School

1957 Robert Herndon, Aircraft Engineer (Life Magazine)

1965 NCF Math Class

1969 Buzz Aldrin on Apollo 11 Moon Mission (NASA)

1970 Colorado School of Mines

1976 Joe Pasquale (right)

1980's "Startrek" TV Re-Runs

1995"Tuskegee Airmen" Movie Scene

1997MIT SR Class

2006 UCSD SR Intro

Present Collector

Public Displays
and Exhibits

News for Friends of the Museum

On-line virtual face-to-face coffee.social get together.
Three times/week. Two times on Wednesday and once on Saturday. The UTC time will change according to Colorado Daylight Savings Time.
  • 2nd shift: WED. at 9 PM Mountain Daylight Savings Time (3 AM UTC THU.)
  • 1st shift: WED. at 9 AM Mountain Daylight Savings Time (3 PM UTC WED.)
  • Weekend 3rd shift: SAT. at 9 AM Daylight SavingsTime (3 PM UTC SAT.)
The meeting are put into three sessions because of Google Meet's one-hour limitations on a free account (Google will give use a 5-minute-warning as the end approaches):
Or use a tiny URL link, which is easy to remember:

2023 Special Fund Raiser for capital Equipment - Completed, Thank you!
22 donors 100% of goal as of Aug 24, 2023
2023 Annual Fund Raiser
11 donors 91% of goal as of Oct 24, 2023

ISRM needs to raise a minimum of $2000 annually, necessary for its programs, exhibits,and ongoing web maintenance. All donations are tax deductable. In our 19th year of being on-line, we have data being downloaded from 118 countries, all at no cost to you! There are no paid staff members, but we need help in keeping ISRM growing and on-line during these challenging times. In 2011 ISRM established a FRIENDS OF THE MUSEUM page to acknowledge its many supporters. You can become a TIER 1 FRIEND OF THE MUSEUM by your donation through Paypal or by check. You can also help by participating in ISRM's Slide Rule Rescue program where you can adopt slide rules. Note that ISRM is a 501(c)(3) non-profit so cash donations are tax deductable. Thank you for your welcome support and kind consideration!
Mail checks or donated items to: ISRM, 1944 Quail Circle, Louisville, CO 80027, USA.

Students from the Collège André-Grasset in Montreal, Canada using slide rules donated by ISRM. Click on the banner for more information.

Dr. Barbara Rooker of the Joplin, Missouri K12 School System, introduced students to slide rule math during 2009 using ISRM's free loaner program. Click banner for more pictures:

Proud Member of


Guidestar Non-Profit Charity Rating

International Slide Rule Museum