International Slide Rule Museum

The International Slide Rule Museum (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! is the world's largest free digital repository of all things concerning slide rules and other math artifacts.

Louisville, CO   |
GuideStar Charity Check

International Slide Rule Museum

EIN: 83-2486423


ISRM is the world's largest free digital repository of all things concerning slide rules and other math artifacts. There are over 7000 Images or PDF's in the ISRM Galleries and Libraries. ISRM is dedicated to the Students, Educators, Scientists and Engineers of the Past and Those Still Present, and to promote the lost art of Numeracy by providing resources and slide rules for education and other historic institutions. We accept donations of slide rules for inclusion in the galleries and financial gifts to support the educational initiatives and its online presence in perpetuity.

Ruling year info


Principal Officer

Michael Vaughn Konshak

Co Principal Officer

Rebecca Ann Konshak

Main address

1944 Quail Cir

Louisville, CO 80027 USA

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Subject area info

Traditional knowledge

Science museums

Historic preservation


Population served info

Age groups

Work status and occupations

NTEE code info

Science & Technology Museum (A57)

IRS subsection

501(c)(3) Public Charity

IRS filing requirement

This organization is required to file an IRS Form 990-N.


Programs and results

What we aim to solve

SOURCE: Self-reported by organization

ISRM has an extensive archive of slide rule specimens, ephemera and artifacts that need to be categorized, scanned, photographed or documented and made accessible through the online galleries at The website currently has over 8000 JPG images and PDF files on display and in its free library download section. Since its inception in 2003, ISRM's website has rapidly become more difficult to navigate because of the manner in which HTML programming codes were implemented and the rapid change in technology of mobile smart phones. Consequently, it had become more difficult to share the ISRM resources. ISRM is in need of paid or voluntary interns to assist the curator in documenting the archive, to ensure that all specimens have suitable accession numbers and have been properly scanned and posted. Additionally, ISRM is in need of a software designer that can help create a new website more in-tune with modern day technologies. A financial trust needs to be created.

Our programs

SOURCE: Self-reported by organization

What are the organization's current programs, how do they measure success, and who do the programs serve?

slide rule loaner program for schools

ISRM provides sets of 25 matching slide rules to be used by educators in elementary through university level, public, private, charter and home schools, to show youth how mathematics was done using logarithmic instruments for the last 200 years. There is no charge to the institutions and their only cost is to return the slide rules by mail after the school term or year depending on the needs of the class. In some cases, for continuing programs, the school is permanently gifted a set.

ISRM provides teaching materials that the students and educators can download at their discretion.

Population(s) Served
Age groups
Social and economic status

Where we work

Our results

SOURCE: Self-reported by organization

How does this organization measure their results? It's a hard question but an important one.

Number of new grants received

This metric is no longer tracked.
Totals By Year
Population(s) Served

Children and youth, Adults

Related Program

slide rule loaner program for schools

Type of Metric

Input - describing resources we use

Direction of Success


Goals & Strategy

SOURCE: Self-reported by organization

Learn about the organization's key goals, strategies, capabilities, and progress.

Charting impact

Four powerful questions that require reflection about what really matters - results.

To create a website that meets the demands of modern day users of mobile phones, to ensure the perpetual longevity of the website's information through a financial trust, to preserve the ISRM library and physical specimens from long term deterioration due to aging.

To expand the art of numeracy by assisting educators with resources and physical slide rules to improve their student's math skills in the STEM fields.

ISRM needs to be given grants and other means of financial support in order to hire assistants to the curator and to hire web-based software developers to create a new website that is functional on desktops for researchers as well as mobile devices for the casual student.

Most museums do not have the ability to provide the ongoing access that is readily available on the ISRM site, as their collections are buried outside of the view of the general public.

ISRM needs to preserve the thousands of hours and thousands of artifacts that comprise the existing slide rule museum, so a contingency plan needs to be pursued in case of the sudden demise of the ISRM founder, to provide resources that would encourage the integration of ISRM into a like 501(c)(3) organization.

To preserve the aging slide rule instruction manuals and books so that users would be able to handle hardcopy reprinted materials in as close to their original form combined in volumes categorized by manufacturer, country or language.

At present, the ISRM activities are performed only by the curator, with advice from an ad-hoc board of advisors on a weekly video meeting.

During the pandemic, the curator published 22 volumes of 550 page reference books preserving the images from 400+ slide rule instruction manuals that over time have become fragile and faded. The goal is to provide these hardcover books to public libraries and universities so that the ephemera does not disappear in hardcopy form. Volumes have been provided in English, German, French, Spanish, Russian and Chinese.

Over 400 slide rule specimens still need to be scanned, edited and posted to the website along with other related ephemera.

A local university that has classes in museum studies has been solicited to see if any students are available that need intern work experience and credit hours. The problem is not having class schedules that align with the immediate needs of ISRM's work requirements.

How we listen

SOURCE: Self-reported by organization

Seeking feedback from people served makes programs more responsive and effective. Here’s how this organization is listening.

done We shared information about our current feedback practices.
  • How is your organization using feedback from the people you serve?

    To make fundamental changes to our programs and/or operations, To inform the development of new programs/projects

  • Which of the following feedback practices does your organization routinely carry out?

    We act on the feedback we receive, We share the feedback we received with the people we serve

  • What challenges does the organization face when collecting feedback?


International Slide Rule Museum

Financial data

SOURCE: Self-reported by organization

International Slide Rule Museum

Revenue & expenses

Fiscal Year: 2022

SOURCE: Self-reported by organization

Contributions, Grants, Gifts $3,625
Program Services $0
Membership Dues $0
Special Events $0
Other Revenue $1,300
Total Revenue $4,925
Program Services $250
Administration $3,600
Fundraising $0
Payments to Affiliates $0
Other Expenses $1,650
Total Expenses $5,550

International Slide Rule Museum

Balance sheet

Fiscal Year: 2022

SOURCE: Self-reported by organization

Total Assets $2,600
Total Liabilities $0
Fund balance (EOY)
Net Assets $2,600


The people, governance practices, and partners that make the organization tick.

Letter of Determination is not available for this organization
Form 1023/1024 is not available for this organization

Principal Officer

Michael Vaughn Konshak

Co Principal Officer

Rebecca Konshak

There are no officers, directors or key employees recorded for this organization

There are no highest paid employees recorded for this organization.

International Slide Rule Museum

Board of directors
as of 09/22/2023
SOURCE: Self-reported by organization
Board of directors data
Download the most recent year of board of directors data for this organization
Board chair

Curator Michael Konshak

Rebecca Ann Konshak


Board leadership practices

SOURCE: Self-reported by organization

GuideStar worked with BoardSource, the national leader in nonprofit board leadership and governance, to create this section.

  • Board orientation and education
    Does the board conduct a formal orientation for new board members and require all board members to sign a written agreement regarding their roles, responsibilities, and expectations? Not applicable
  • CEO oversight
    Has the board conducted a formal, written assessment of the chief executive within the past year ? Not applicable
  • Ethics and transparency
    Have the board and senior staff reviewed the conflict-of-interest policy and completed and signed disclosure statements in the past year? Not applicable
  • Board composition
    Does the board ensure an inclusive board member recruitment process that results in diversity of thought and leadership? Not applicable
  • Board performance
    Has the board conducted a formal, written self-assessment of its performance within the past three years? Not applicable

Organizational demographics

SOURCE: Self-reported; last updated 9/22/2023

Who works and leads organizations that serve our diverse communities? Candid partnered with CHANGE Philanthropy on this demographic section.


The organization's leader identifies as:

Race & ethnicity
Gender identity
Sexual orientation
Heterosexual or straight
Disability status
Person with a disability

The organization's co-leader identifies as:

Race & ethnicity
Gender identity

Race & ethnicity

Gender identity


Sexual orientation