Know your visa & tax days before you book — not after the border does
Brain · loading
⚠️ Decision support, not legal or tax advice. Rules carry a confidence + as-of date; anything LOW or stale is shown as "verify", never asserted. Click any ⓘ source for cited passages from the brain (in-browser, zero-egress) — it abstains when out of scope. Your trips stay on this device by default; sign in only for the forwarding inbox — those synced trips are stored in your account.
Schengen Area · 90/180 ⓘ source
–days remaining
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– of 90 days used in the rolling 180-day window (shared pool across all member states · entry & exit days both count).
I hold a residence permit / nomad visa for — (dual-quota)
Alerts
Plan a future route — legality check
Forwarding inbox beta↻ refresh
Email receiving is rolling out. Fastest path today: Import → paste a flight email (same parser, instant). Confirmations sent to the address below appear here to confirm into your ledger.
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Pending imports
Trip ledger
Country
Entry
Exit
Days
Zone
Permit?
Per-country exposure (visa + tax residency)
Bordermath · · ruleset · built 2026-06-25 Illustrative rules · cited, zero-egress retrieval · not legal, tax, or financial advice · Privacy · Terms · Data controller: Agni · hello@agni.work
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Rule
From the Bordermath brain — cite-or-abstain
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Add your trips
Three ways in — pick whatever's least effort.
1 · Paste a flight confirmation email
Paste any airline/booking confirmation. We extract the flights and propose your country stays — nothing is added until you confirm.
2 · Forward to your inbox — with an account
Sign in (email code) on the hosted app to get a private forwarding address like trips.<your-token>@inbound.bordermath.app. Forward confirmations there and they appear here to confirm. Built & tested; activates on deploy.
3 · Manual
One per line: Country, YYYY-MM-DD, YYYY-MM-DD
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Audit log
Every verdict records the ruleset version + timestamp that produced it (traceability, PRD P0.7). Newest first.
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Sign in
Passwordless — we email you a 6-digit code. Unlocks your private forwarding inbox so you can forward flight confirmations and have trips appear automatically.
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Welcome to Bordermath 👋
Bordermath tells you how many days you can legally stay — your Schengen 90/180 allowance, per-country visa caps, and tax-residency thresholds — so you know before you book, not at the border.
How it works — 3 steps
1Add your trips — past and upcoming. Type them in the Trip ledger, Import a flight confirmation email (we read the dates for you), or forward them to your inbox after signing in.
2See where you stand — days remaining in each window, with alerts when you're cutting it close, each backed by a cited source.
3Plan a future route — add a planned stay and get an instant legal / breaks-the-rule verdict before you commit.
Your trips stay on this device by default. Signing in is optional — only needed for a personal forwarding email address. Not legal or tax advice.