Methodology and sources

The cost table, and the two books it is printed in

The purchase table is the same in both editions. It first appears as an optional rule in the 2014 book and is carried into the 2024 rules with the costs unchanged, which is why one calculator can serve both and why the edition switch changes where your bonus comes from rather than what a score costs.

Player's Handbook (2014) — page 13

“Variant: Customizing Ability Scores”. The 27-point budget, the 8-to-15 purchase range, and the cost table the homepage calculator uses.

Player's Handbook (2024) — page 38

Customizing Ability Scores, with the Standard Array by Class table. The same 27-point budget and cost table carried into the 2024 rules, alongside the standard array and the move of ability increases from species to background.

Two checks on that table worth stating: the standard array of 15, 14, 13, 12, 10, 8 prices at exactly 27 through it, and 12,282 different arrays spend the 27 points exactly. Both figures are computed from the table above at build time.

Species and background bonuses, and when they apply

Almost every disagreement about a point buy total comes from applying the increase at the wrong moment. The budget buys the score; the increase is added afterwards and is never charged for. Both editions work this way and only the source of the increase changed.

1. Buy first, within 8 to 15. The budget can only produce a score from 8 to 15. Fifteen is the hard ceiling on a purchase, and it costs 9 of the 27 points.
2. Then add the increase, free of charge. A +2 lands on the bought score at no cost, so a purchased 15 becomes a 17. This is why 17 is the practical maximum at first level and why buying a 14 and adding +2 is cheaper than trying to buy higher.
3. Under the 2014 rules the increase comes from the species. Each species grants a fixed set of increases, and a few grant a choice of where they land. The site routes those through the same picker rather than pretending the choice does not exist.
4. Under the 2024 rules it comes from the background. The background grants either +2 and +1 to two abilities or +1 to three, assigned among the three the background names. Species no longer changes ability scores at all.
5. Odd scores are where points get wasted. Because the modifier rounds down, a bought 15 and a bought 14 both give +2 until an increase arrives. Spending the extra 2 points on the 15 only pays if a +1 or +2 is coming to make it 16 or 17.

The modifier formula

The modifier is the score minus ten, halved, rounded down. That single formula covers the whole range and is the reason the cost table is shaped the way it is: the expensive scores are the ones that cross a rounding boundary.

modifier = floor( ( score − 10 ) ÷ 2 )

The purchasable range is 8 to 15; the full table from 1 to 30 is on the ability modifiers page, which is the only page here that carries the whole range.

Pathfinder 1st Edition

Pathfinder 1st Edition is a separate system handled by separate code. Every ability starts at 10 rather than 8, the range runs from 7 to 18, and buying a score below 10 refunds points into the pool. Because the two tables share nothing, the site keeps them in two modules that share no cost function, and the test suite asserts that they disagree at every score both of them price.

Purchasing Ability Scores

The 7-to-18 purchase table, the base score of 10, and the point refund for scores bought below it. Scores run 7 to 18 from a base of 10.

Campaign budgets — a convention, not a printed default

Which budget a table actually uses. The three figures are the conventional power levels, with Pathfinder Society organised play standardising on 20; a home game uses whatever its GM sets. The three the Pathfinder calculator offers are 15, 20, 25.

House-ruled budgets and cost curves

The custom page lets the pool, the floor, the cap and the cost curve all move. Inside 8 to 15 its standard curve reproduces the published table exactly, and a test pins that equivalence so the page cannot drift away from the real rules. Outside that range there is no printed table to follow, so those costs are extensions of a published curve and every one of them is labelled "Extrapolated" where it appears.

Costs above 15 and below 8 on the custom page. No published table prices those scores, so they are extensions of a published curve and are labelled "Extrapolated" wherever they appear. The custom calculator is where those appear.

What this site deliberately leaves out

Some things are missing on purpose. Leaving them out keeps the tool checkable, and pretending otherwise would be worse than the gap.

• Rules text is not reproduced. Costs, formulas and thresholds are facts about the system and are explained here; the prose of a rulebook is not open content and is not reprinted.
• Pathfinder 2nd Edition has no point buy to model. It assigns boosts in a fixed sequence, so there is no budget and no purchase table, and no page here pretends to calculate one.
• Class recommendations stop at level 4. The proficiency bonus is +2 through those levels, which keeps every consequence on a class page a single honest number instead of a range across twenty levels.
• Feats, magic items and anything that raises the cap above 20 are out of scope. They change ability scores after character creation, which is a different question from what a score costs to buy.
• Encumbrance, carrying capacity and the other tables that read a raw score are not modelled. They depend on equipment the site knows nothing about.
• No optional rule from a third-party supplement is included, because there is no single version of it to cite.

How the numbers are checked

The arithmetic is not trusted, it is tested. The cost table is checked against an exhaustive sweep of every legal array, the 4d6 distribution is enumerated from all 1,296 outcomes rather than sampled, and every array the site recommends is verified to cost exactly 27 before it can ship. The build also refuses to publish pages that repeat each other, which is why each class page argues from that class’s own numbers.

The dice odds are a worked example of that: rather than rolling a large sample, the build enumerates all 1296 outcomes of four six-sided dice and counts them, which is why the figures on the rolling page are exact rather than approximate.

Corrections

Errors get corrected in public. The changelog records what changed and when, including the corrections — a page here once claimed that a spent 27-point budget totals 72, which is the standard array’s total and not a property of the budget at all. That entry stays in the log.

Every source in one list

Where to go next

• Terms of use — the trademark position and the licence the rules content here relies on.
• Report a disagreement — if a figure here does not match your book, that is worth knowing about.
• Use the calculator these sources describe