Free card tools
6 calculations worth doing before you spend money, each one running the same arithmetic our own analysis uses. They work without an account, and every assumption is named on the page rather than buried in the result.
Card Grading Break-Even Calculator
Should you grade it? The honest version: not a predicted gem rate, but the gem rate you would need to break even.
Open the calculator →eBay Best Offer Calculator
What your offer costs all-in, and whether a human will ever read it.
Open the calculator →Compare Two Baseball Prospects
Two players, the measures that decide a prospect card, and no verdict we cannot support.
Open the calculator →Card Selling Fee Calculator: What You Actually Clear
A $190 sale does not pay $190. The line-by-line version, with the fee rate as an input rather than a hidden constant.
Open the calculator →Sold Comp Fair Value Calculator
Your own sold comps, run through the real valuation: a range rather than one confident number, and the weight each sale actually carried.
Open the calculator →Bowman Parallel Scarcity Calculator
Is the /99 worth 4× the base auto? Compare print run against the price actually being asked.
Open the calculator →
Start from the question you have
Nobody wakes up wanting a parallel scarcity calculator. They want to know whether the /99 is worth four times the base, and the tool is just where that answer lives. Each of these is here because the arithmetic is genuinely easy to get wrong in a way that costs money — a fee charged on shipping you forgot about, a grading submission that needed a gem rate nobody hits, an offer that an automatic rule declined before a human read it.
- “Is it worth paying to have this card graded?”
- Card Grading Break-Even Calculator
- “What should I offer, and will the seller ever see it?”
- eBay Best Offer Calculator
- “Which of these two prospects is the better card to own?”
- Compare Two Baseball Prospects
- “If it sells for $190, what actually reaches me?”
- Card Selling Fee Calculator: What You Actually Clear
- “Five sold prices disagree — what is this card actually worth?”
- Sold Comp Fair Value Calculator
- “Is the numbered parallel worth its premium over the base?”
- Bowman Parallel Scarcity Calculator
What these have in common
Every result is a URL. The calculations run on the server from the query string, so a result is a link you can send someone, and the page works with JavaScript switched off. Nothing you type is stored, and nothing needs an account.
Assumptions are inputs, not constants. Where a number is somebody's rate rather than a fact — the marketplace fee, the grading cost — it is a field you can change, defaulting to the same value this site uses in its own analysis so the tools and the product cannot quietly disagree about the world.
An unanswerable question gets no answer. Leave a field blank and the calculator says what it needs rather than treating the gap as a zero and printing a confident wrong number. That rule is the same one the rankings follow, and it is the reason these are worth trusting with a real decision.
The reasoning behind each one is written out in the guides, and the formulas our card scores use are documented on the methodology page.