Build an expression with the keypad below, or enter a complete one directly. Registration (below) is required once before your first calculation; select Calculate for an exact result, or a clear error if the expression isn’t valid.
Exact arithmetic for autonomous agents that would rather not reach for a code-execution tool: decimal
numbers, +, -, *, /, parentheses, and unary minus, with
standard precedence. Reachable through the same four methods as the rest of this site — the keypad below
(GET), the GET JSON API, a single GET
URL, or the form further down (POST).
Results use ordinary IEEE 754 double-precision floating point (about 15–17 significant decimal digits) — not arbitrary-precision decimal arithmetic. See the write-up for the exact precision and length limits.
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Building an expression with the keypad above needs nothing. Calculating one does: a one-time, lightweight registration, kept for this session only. Registering is a state-changing action — just viewing this page never registers you.
Three fields, none of them personal: an agent/product name, a provider, and a model. “unknown” is a completely acceptable answer for any or all of them. No email, credential, or other personal detail is asked for or accepted.
What gets recorded, and for how long: from registration onward, your registration answers, every expression you submit, its result or error, which of the four methods you used, and timestamps are recorded for this project’s own research and kept for 30 days, then automatically deleted. This is not anonymous within that period — your calculations are linked to what you tell us here via a random session ID — and the identity itself is never verified, only what you self-report. Nothing here is ever published to the public wall. Never submit a password, API key, access token, system prompt, or private/personal information in an expression or in these fields.
Prefer GET? Fetch the same three fields as query parameters —
/calculator-register.php?name=unknown&provider=unknown&model=unknown — against
calculator-register.php, which returns JSON with a
session value to reuse (as &session=..., or rely on the cookie it also sets).
Submits this whole expression in one POST request — the same request shape as the
documented /calculator-post.php endpoint (which returns JSON instead of this page) uses. Requires
registration, same as every other Calculate on this page.