Credits are a pricing abstraction. They sit between the number a buyer reads on a plan card and the number that actually matters, which is what one finished, usable output costs. Most of the time the two are close enough that nobody checks. Sometimes they are not, and the gap is entirely legal, disclosed in a sentence most people skip.
We build CasaNova Labs, an AI studio for real estate photo and video editing, so we spend a lot of time reading competitors' pricing pages the way a buyer at volume would. This is the one normalization step that changes the ranking of tools more than any headline discount, and it takes about two minutes per tool.
Credits are not outputs
A plan advertises a monthly credit balance. A separate line, usually further down, tells you how many credits one operation spends. The cost that matters is the second number divided into the first, then divided into the price.
Here is a real grid. Roomagen, rates checked July 2026, lists a free tier at 6 credits, Starter at $12 a month for 60 credits, Pro at $29 for 200, and Business at $79 for 700. On its own that reads like roughly 60 to 700 units of value per tier. But one image spends two credits. So the delivered-image count per tier is 30, 100, and 350, and the real grid is:
- Starter: $12 / 30 images = $0.40 per image
- Pro: $29 / 100 images = $0.29 per image
- Business: $79 / 350 images = about $0.23 per image
None of those numbers are hidden or improper. The two-credits-per-image rule is stated plainly. But the plan card shows you 60, 200, 700, and your brain anchors on those. The number you will actually budget against is 30, 100, 350.
The formula
For any credit-based media tool, normalize before you compare:
cost_per_output = plan_price / (plan_credits / credits_per_output)
Run it for every tier, not just the one you think you will buy, because the per-unit curve is where the tiers actually differ. Roomagen's curve above bends about 43% from smallest to largest tier, which is a genuinely tiered grid and, per unit, lands under a lot of the market including ours. A tool that charges one credit per output and a tool that charges two can advertise the same credit price and cost you double or half. The headline price tells you nothing until you divide it down.
What the unit price still does not capture
Cost per output is necessary, not sufficient. Once every tool is on the same per-output axis, three things decide the actual bill that the axis hides:
The credit-to-output ratio can vary by operation. One image at two credits is simple. A tool that spends two credits on a staging pass and five on a video clip has two different real prices under one balance. Normalize per operation type you will actually run, not once for the whole tool.
Coverage under one balance. If photo and video draw from the same credits, the per-image number understates value, because the same budget also buys the more expensive operation. If they are separate products with separate balances, two cheap-looking plans can be one expensive stack. We put photo and video on one balance for exactly this reason, and it makes our per-image number look worse in isolation and better in a real month.
Expiry. Credits that reset monthly are a use-it-or-lose-it liability on anything with uneven volume, which real estate is. Rollover changes the effective price of every credit you do not burn. It rarely appears in the per-unit math and often dominates it.
Why this belongs in an engineering conversation
If you are building the tool, the ratio is a product decision with a trust cost: a two-to-one credit rule is defensible, a variable and unpredictable one trains buyers to distrust the balance. If you are buying, it is a procurement step you can script. Pull each competitor's plan price, credit balance, and credits-per-operation into three columns, apply the formula, and the tools re-sort themselves in front of you. The winner on the plan card is frequently not the winner on the third column.
We wrote the full worked version of this, tier by tier and in each tool's own currency without inventing an exchange rate, as a direct comparison: CasaNova Labs versus Roomagen for listing photos. It says plainly where the per-image price goes the other way, because on that axis it does. If you want to run the same math against our own grid, the pricing page lists every tier and the free trial is 10 transformations with no card, where one transformation is one delivered image.
The point is not that any one tool wins. It is that the number on the plan card is the wrong number, and the right one is two minutes of division away.
