ISRM is the world's largest free digital repository of all things concerning slide rules and other math artifacts.
As of 2026, ISRM is celebrating its 23th 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.
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ISRM Advisory Board of Directors.
KEEP ISRM FREE!
ISRM Restructuring: As of January 1, 2026 The entire ISRM archive, aka the Michael Konshak slide rule collection and library, has been shipped, in its entireity, from Colorado to Long Island, New York into the care of the new ISRM custodian, Kurt Dietrich, for preservation. It was becoming difficult for the curator to manage the day-to-day operation of the physical museum, which involved making spare parts and shipping slide rules and books that people wanted to adopt.. Please welcome, Kurt Dietrich to the ISRM family.
When Kurt is able, sometime in February 2026 he will take on the burden of doing many of the services of providing parts, slide rules and manuals to fellow collectors. Kurt has total ownership and autonomy on how to manage the collection. Donations of physical slide rules will need to be sent to the custodian.
The 501(c)3 Non-Profit and ISRM museum website and digital galleries will still continue to be maintained and updated as has been done for 23 years by Michael Konshak, the ISRM Curator in Louisville, Colorado. Tax-deductible donations used to support the website will continue to be accepted during the 2026 tax year.
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. or Press Post and Chat on
ISRM @sliderulemuseum and
Instagram page
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. Note: The curator's life is going through some restructuring, and may not be available to participate. The sessions are open to whoever shows up.
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.)
Daylight Savings starts on November 3 and ends the 2nd Sunday in March
2nd shift: WED. at 9 PM Mountain Daylight Savings Time (2 AM UTC THU.)
1st shift: WED. at 9 AM Mountain Daylight Savings Time (2 PM UTC WED.)
Weekend 3rd shift: SAT. at 9 AM Daylight Savings Time (2 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):
ISRM needs to raise a minimum of $2000 annually, necessary for its programs and ongoing web maintenance. All donations are tax deductable. In our 22th 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 using slide rules donated by ISRM. Click on the banners for more information.
ISRM @sliderulemuseum
Instagram page
