Slack for Nonprofits: Free Pro, 85% Off, and Who Is Excluded

Slack has one of the most generous nonprofit offers in software, and most write-ups stop at the headline. The detail that decides what you pay is who counts as a member, who Slack excludes, and what the free plan now does to your history. All three are below, read from Slack’s own help pages on 8 November 2026.

What Slack costs a nonprofit

Slack’s nonprofit discount article sets out two offers. On Pro, “workspaces with 250 or fewer members” get “a free upgrade, and an 85% discount for workspaces above that size.” On Business+, Slack offers “workspaces of any size an 85% discount.” Enterprise customers with “deployments of 1,000+ members” can ask for the discount too, with no percentage stated.

List prices are from Salesforce’s Slack pricing page, which showed US dollars: Pro is $8.75 and Business+ $18 a user a month on monthly billing, and the page says annual billing “saves you approximately 16%.” Slack’s June 2025 announcement put Business+ at $15 a user a month on annual billing, up from $12.50, and said Pro pricing would stay the same. Slack’s own pricing page showed us Indian rupees, so we have not printed an annual Pro figure we did not see in dollars. The nonprofit prices are our arithmetic: 15% of list.

The 85% matters because Business+ went up in 2025. A small charity that priced Slack at $12.50 a user from an old article is now looking at $15, and $2.25 after the discount. Slack also says plainly that it does “not offer refunds for subscription fees paid prior to being approved,” so apply before you upgrade, not after.

What that means in dollars

Four illustrative organizations, at list price and with the nonprofit offer. Annual billing is used for Business+ because that is where Slack publishes a dollar price; Pro is shown on monthly billing for the same reason.

The food pantry is the case most small charities are in. Six staff on Pro is a free upgrade, and the thirty volunteers do not need to be members at all if each only needs one channel, as explained below. The network row shows the cliff at 250 members: at 251, Pro stops being free and becomes 85% off for everyone, not just the members above the line.

Who qualifies, and who Slack excludes

Slack asks for “a valid charitable status with either the IRS (in the United States)” or a local charity regulator or “local TechSoup Global partner.” It does not name 501(c)(3) specifically, and it publishes no country list. The exclusion list is the part to read before you apply, because it is broader than most charities expect:

• “A legislative or political organisation”
• “A church, association of churches or other religious organisation”
• “A school, college, faculty group, alumni group, fraternity or sorority”, which Slack sends to its education programme instead
• “A government office”
• “An organisation that attempts to influence public opinion”
• “A hospital, an organisation involved with health insurance or group health plans”
• “A private grant-making, independent or operating foundation”

Two of these catch organizations that think of themselves as ordinary charities. A private foundation is a 501(c)(3) and is still excluded. And “attempts to influence public opinion” is wide enough that a 501(c)(3) running a public campaign could be asked questions; a 501(c)(3) can lobby within limits under federal law, as our lobbying guide explains, but Slack’s eligibility is Slack’s rule, not the IRS’s. A 501(c)(4) should assume it is out. Slack also excludes groups that discriminate or promote a religious doctrine in their mission.

We read the article in Slack’s British wording, “Slack for Charities”, because that is what its server returned to us. The US title is “Slack for Nonprofits.” The terms should be the same, but if a clause decides your eligibility, read the US page yourself.

How to apply

1. Decide which workspace. Each workspace needs its own application. If you have one for staff and one for a coalition, they are two applications.
2. Have a Workspace Owner apply. Only an owner can submit the form, which asks for your legal name, location, website and a description of your work.
3. Be ready to be verified by TechSoup. Slack names TechSoup as “a service that helps to review and validate not-for-profit and charitable status.” Keep your IRS determination letter to hand; the name on your application should match it.
4. Wait up to three days. Slack says it will apply the free upgrade or discount “within three days” of approval.
5. Then upgrade. Fees paid before approval are not refunded.

Slack publishes no re-verification or renewal rule. Assume Slack can ask again, keep your status current, and reapply if it changes, which Slack says you may do.

Volunteers and board members: who you pay for

This is where a Slack bill is won or lost, and where most guides say nothing. Slack’s guest article separates two kinds of guest:

• Single-channel guests “are free and can only access one channel.” Slack allows “up to five guests” for “every paid active member in your workspace.”
• Multi-channel guests are “billed as regular members.”

So a volunteer who only needs the #saturday-shift channel can be a free single-channel guest, and ten paid staff can host fifty of them. A board member who needs #board and #finance is a multi-channel guest, billed as a member. The practical design is one channel per volunteer group, and either a single #board channel for trustees or full membership for them.

Two cautions. Guests “are only available on Slack’s paid subscriptions,” so you need at least the free Pro upgrade before you can add any. And the guest ratio is defined against paid members; on a Pro workspace upgraded free, ask Slack how it counts before you plan on fifty volunteers. Members still count toward the 250 that keeps Pro free, so turning occasional volunteers into guests also keeps you below the cliff.

Slack’s fair billing policy helps with seasonal volunteers on paid plans. A member who “hasn’t used Slack in over 28 days” stops being billed, and Slack credits the unused time. The credits “have no currency or exchange value” and are not refunded, so they only reduce future bills. For managing volunteer schedules themselves, Slack is the wrong tool; our volunteer management software guide covers the ones built for it.

What the free plan does to your records

Many small charities run on Slack’s free plan without noticing the limits have tightened. From Slack’s free plan article:

The row that matters most is the first. The free plan shows only “the most recent 90 days of message and file history,” and since 26 August 2024 Slack has been “deleting messages and files more than one year old from free workspaces.” If a grant decision, a safeguarding report or a staff complaint lives only in a free Slack workspace, it will be gone. On paid plans, Slack’s retention article says data “is kept for the lifetime of your workspace by default.”

Export is the second records issue. Slack’s export article says Free and Pro owners can export public channels only; private channels and direct messages are not available unless an owner applies. Business+ owners can apply for a self-serve tool that includes them. For most charities on free Pro that means: anything you might need to produce later, for an auditor, a funder or a lawyer, should be in a public channel or saved elsewhere.

Slack is also not a minute book. A board that agrees something in a thread has had a conversation, not a meeting. Record decisions properly with our board meeting minutes template or, between meetings, a written board resolution, and keep the internal controls rule that payments are never approved in chat.

Slack AI, now in the plans

Slack stopped selling AI as an add-on. Its plan changes article says “The Slack AI add-on is no longer available to purchase on the Slack website,” and existing add-on buyers move to the new plans at “their first renewal after August 17, 2025.” Pro now includes “conversation and thread summaries and huddle notes.” Business+ adds search, recaps, translation, file summaries and workflow automation; Enterprise+ adds enterprise search. Agentforce and third-party apps are bought separately.

Because AI is now part of each plan rather than an extra, the 85% Business+ discount should cover it. Slack does not say so in its nonprofit article, so confirm before you budget on it. Before anyone summarises a channel holding donor or client details, agree the rules in an AI use policy; our guide to AI data security covers what to check.

Do you need Slack at all?

Many charities already have a chat tool they are not using. Microsoft 365 for nonprofits includes Teams, and Business Basic is free for up to 300 users. Google Workspace for Nonprofits includes Google Chat at no charge. If your staff live in Outlook or Gmail all day, a second chat tool is another place for decisions to get lost.

Slack earns its place in three situations. You work with partners or volunteers outside your email domain, where free single-channel guests keep the cost down. You rely on integrations: Slack’s app directory is broad, and the free plan’s 10-app limit disappears on Pro. Or your team already uses it and the move would cost more goodwill than it saves. For video, Slack’s huddles are fine for quick calls; for webinars and large meetings, see Zoom for nonprofits. For task tracking, a channel is not a project plan; our project management software guide compares the tools that are.

Setting it up so it stays useful

• Name channels by purpose, not by person. #grants, #events-gala-2027, #volunteers-saturday. People leave; channels should not have to.
• Keep one #announcements channel that only staff leads post in, so important notices are not buried in chatter.
• Use single-channel guests for volunteers by default, and review the member list each quarter. Fair billing removes the cost of inactive members on paid plans, but not the access.
• Remove leavers the day they go, as part of the same offboarding checklist that removes email and finance access.
• Decide what never goes in Slack: passwords, bank details, donor card numbers, client case notes. A shared password manager or your case management system is the place for those.

Where these figures come from

We read Slack’s help articles on the nonprofit discount, the free plan, guests, fair billing, data retention, export and plan changes, Slack’s June 2025 pricing announcement and Salesforce’s Slack pricing page on 8 November 2026. Slack’s own pricing page showed Indian rupees to us, so dollar prices come from Salesforce’s page, which offers a currency selector, and from Slack’s announcement. Nonprofit prices are our calculation at 15% of list and exclude tax. TechSoup’s Slack page could not be read from our connection. Slack has no commercial relationship with this site and we take no referral fees. For other vendors’ programmes, see nonprofit software discounts.

This is reference information, not legal or tax advice. Rules vary by state and change over time. For a decision that carries real consequences, check the current text at irs.gov or your state registry, and talk to a nonprofit attorney or CPA.