TL;DR
- Every AI subscription counts something, either to charge you or to decide when you need a bigger plan: people, credits, or in some newer tools, agent days and agents working at once.
- The price line and the thing that moves you up a plan aren't always the same. pen.dev, a design tool we use for part of our carousels, published paid plans that haven't launched yet: billed per user, but separated by agent days, agents at a time and image generations.
- We have to choose between its free plan and Pro, and the number that decides it is one we don't have.
- The fix is three columns next to each AI subscription: what it is, what it counts, and whether you have that number.
- Start here: fill in the three columns for one tool. If the third one stays blank, that's what you came to find.
The short answer. An AI subscription counts something, to bill you or to move you up a plan: each login, each credit spent, or, in some newer tools, each day an AI agent works or how many run at once. Hub365 AI hit this with a design tool whose upcoming paid plans bill per user but split on other limits. The fix: beside each AI subscription, write what it is, what it counts, and how much of that you used last month.
You can probably say, roughly, what each AI tool costs the business a month. What that money is measuring is a harder question. It's also the answer you need on the day you pick a plan.
None of this picks a plan for you, and it won't tell you what any tool should cost. It does something smaller that comes first: it shows you what the bill is measuring, so you can check that against how the business actually uses the tool.
1. Every AI plan measures something, and the price tag may not say what
When you sign up for an AI tool, the plan page usually shows a price and a unit next to it. "Per user, per month" is the most common one. What's easy to miss is that the unit on the price tag and the limit that pushes you into the next plan can be two different things.
An agent, in plain terms, is an AI assistant that does tasks inside a tool for you: it builds, edits or tidies things while you do something else. Some tools put limits on how many days a month an agent can work, or how many can work at the same time.
Headcount stopped being the only budget question
The usual budget question for software is "how many of us need a login?" With some AI tools you also have to ask how much work you hand to the machine, and how much of it happens at once. A team of two can hit a limit that a team of ten never touches, depending on how they work.
2. Our own open decision: free plan or Pro
Part of our carousels are designed in pen.dev, which used to be called Pencil. It recently published the plans it will charge for. Its pricing page says the plans are coming soon and that pen.dev stays free until they launch. It gives no date.
Here's what the plans list, straight from that page:
- Free: the full editor, 5 agent days a month, 25 generated images or SVG graphics a month, and one agent at a time.
- Pro: billed per user per month, unlimited agent days, 350 image generations a month, tools to manage a team, usage tracking, and up to 3 agents working in parallel.
- Ultra: also billed per user per month, 750 image generations a month, up to 6 agents in parallel, and one shared pool of usage for the whole team.
Its terms of use say the same thing about billing: paid plans are priced per user, monthly or annually.
And its definition of an agent day: any day you work with an agent in pen.dev, whether the agent is built in or connected from another tool. Usage is unlimited within that day, and days you don't use an agent don't count. Two things follow from that. A day counts once whether the agent worked for five minutes or all afternoon. And three small tasks on three different days use three days, while the same three tasks in one afternoon use one.
"Per user" is the price tag, not the reason you'd upgrade
Read the three plans side by side and most of what changes has nothing to do with headcount. From Free to Pro, agent days, image generations and agents at a time all change. From Pro to Ultra, agent days don't change at all, since both list them as unlimited. What changes there is how many agents can work at once and how many images you get.
So our decision, open since October 1, is whether the free plan's 5 agent days a month cover what we do there, or whether we move to Pro. Today pen.dev doesn't charge us anything, so there was never a reason to count agent days. To decide, we need exactly that number, and we don't have it yet.
3. What your bill may be counting, and where it catches you off guard
You don't need to memorize these. Your tool may use a different word, like minutes, messages or conversations. The question stays the same: what is it counting? The last two on this list are the ones from our case.
Per person. You pay for each login. Where it catches you: the plan you outgrow is set by headcount, so the number to know is how many people have their own login today.
Per credit. You buy a bucket of credits and each task spends some. Where it catches you: the bucket runs low before the month ends and the next step up looks like the only way out. pen.dev's Ultra plan, for example, describes its usage as credits shared across the whole organization. The number to know is how many credits you spent last month.
Per agent day. The plan caps how many days a month an agent can work. Where it catches you: spreading small jobs across the week burns days faster than doing them in one sitting. The number to know is how many days last month an agent worked in that tool.
Agents at a time. The plan sets how many agents can run at once, and getting more means a bigger plan. Where it catches you: you only find out you needed two when you're waiting on one. The number to know is whether you ever had work that needed more than one at the same time.
Last month we went through what Meta's new AI plans could cost you each month. That piece was about the amount. This one is about the unit behind it. The amount is what you pay. The unit is what makes it go up.
4. The empty column
Here's the fix: three columns next to each AI subscription you pay for, or plan to pay for.
| Column | The question | How to fill it in |
|---|---|---|
| What it is | Is it on the list, including the ones that are free today? | Add every AI tool the business uses, one per row |
| What it counts | Do you know the unit the plan is built on? | Open the plan or pricing page and copy the unit and the limit that separates your plan from the next one |
| Do you have the number? | Do you know how much of that unit you used last month? | Look in the usage or billing section of the account. If the tool doesn't show it, write "don't know" |
The first two columns take a minute each. The third sometimes takes a month of counting.
Here's how our own row reads:
| What it is | What it counts | Do we have the number? |
|---|---|---|
| pen.dev, design | Paid plans (not launched yet) billed per user; separated by agent days, agents at a time and image generations | No. We don't have a record of how many days a month an agent worked there |
The blank box tells you what to count next
A blank third column usually means nobody ever asked for that number, because nothing depended on it yet. Now something does, and you know which number to start keeping.
5. Where this sits next to the tool list you may already have
Five weeks ago, on another Friday, we suggested a two-column sheet in the moving test for where your client data lives. That sheet asked what stops working if a tool disappears tomorrow. These three columns ask something else: what the tool is counting while you keep using it. If you already did that sheet, add this as a second pass on the same list.
And if one of the tools on your list is supposed to help you get found online, the map of SEO, GEO and AEO helps you write down which of those three jobs it's actually doing before you look at what it counts.
The third-column conversation
Todd: The timing is the part nobody gets to choose. A free tool announces paid plans, or the work outgrows the plan you're on, and now there's a decision with a deadline. If the third column is blank that day, you end up picking off the price tag.
Naty: And it's an easy number to put off, because not having it doesn't hurt on the day you skip it. A blank box can also feel like getting caught not paying attention. So the sheet waits for later, and later turns out to be that day.
Todd: Then the count has to start before the date shows up, not on the morning of. A few weeks of rough tallies is enough to choose with.
Naty: For years I spent only a small part of what came in and invested the rest. On a plan page, the careful part happens before you click. Once you're on the plan, the plan sets the pace.
The one thing to do this week
- Pick one AI tool the business pays for, or one that's free today and will have paid plans. Just one to start.
- Fill in the first two columns. Write what it is, then open its pricing page and copy the unit it counts and the limit that separates your plan from the next one.
- In the third column, write how much of that unit you used last month. Check the account's usage or billing section first. If the tool doesn't show it, write "don't know" and start keeping your own count from today.
With a number in the third column, you're comparing plans on something real. With a "don't know," you have your first thing to measure before anyone upgrades.
Frequently asked questions
What does "per user" mean on an AI tool's pricing page? It means each person with their own login is billed separately, usually per month. On some tools that's the whole story. On others, the plans are also separated by usage limits, so two people on the same plan can run into a limit long before you add a third.
What is an agent day? It's the unit pen.dev's published plans use for agent work: any day you work with an AI agent in the tool counts as one day, however long the agent works. Days you don't use an agent don't count. Its free plan includes 5 a month, and its Pro and Ultra plans list them as unlimited.
Where do I find how much of an AI subscription I've used? Start with the usage or billing section of the account, signed in as the business. Some tools show it on every plan and some only on paid ones. On pen.dev, for example, usage tracking is listed as part of Pro. If you can't find it, write "don't know" and keep your own count for a month.
Can a tool bill per user and still move me up a plan for something else? Yes. pen.dev is an example: its paid plans, which its page says haven't launched yet, are priced per user, but they're separated by agent days, agents at a time and image generations. That's why the second column asks for the limit between plans, not just the unit on the price tag.
I couldn't fill in the third column. Do I need to change plans? The blank box on its own doesn't answer that. What it gives you is the thing to measure: count for a month, then compare plans with the number in hand.
To close
An AI bill always counts something. The price tag tells you part of it, and the limits between plans tell you the rest.
Three columns put it on one page: what the tool is, what it counts, and whether you know how much of it you used. The third is where the work is, and even a blank there tells you something you didn't know this morning.
Got a tool whose plan page you can't make sense of? Pull it up on a call with us and we'll go through it line by line until you know what it counts.
The AI Edge goes out this afternoon at 4 ET, with one practical AI move for your business each week. Get it in your inbox.
Thanks for sitting through the fine print with us. A "don't know" in the third column is a fine place to start, as long as it isn't still there next month.
Keep reading
- Meta put a price on the AI you were already using - the amount, back in September
- You rent the tool. You own the asset. And almost nobody can tell which is which in their own business. - the two-column sheet and the moving test
- If AI gets your price wrong, ask it where it got the number - the price AI quotes for you
- SEO vs. GEO vs. AEO: which one your business needs in 2026 - the full map
- pen.dev pricing - the plans and the definition of an agent day
Sources
- pen.dev, "Pricing," accessed October 8, 2026 - plan limits, billing per user, agent day definition - https://www.pen.dev/pricing
- pen.dev, "Terms of Use," effective October 6, 2026, section 6 - paid plans priced per user, monthly or annual billing - https://www.pen.dev/terms-of-use
