usefulweb.site Hidden Fee Finder

Money-saving & comparison

Hidden Fee Finder

Paste a quote, contract or invoice and see every fee, tax, penalty and add-on.

One cost per line. Supported amount formats: 1,234.56 / 1.234,56 / €12 / 12 EUR / 12,50 € and percentages like 19% or 2.5 %.

Or: line items

Optional alternative to pasting text. Rows are appended after the pasted lines.

Or: line items
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Try an example: Hotel booking with resort fee and conditional charges · German rental quote

How it works

Paste the lines of a quote, rental contract, booking or invoice (English or German). Hidden Fee Finder extracts the amounts, classifies each line with transparent keyword rules (base price, fee, tax, surcharge, penalty, deposit, discount, insurance/add-on, recurring), flags conditional penalties and optional add-ons, and shows how much of the total is not the base price.

  • Each non-empty line is scanned for amounts. A number counts as money if it has a currency marker (€, $, £, EUR, USD, GBP, CHF…), exactly two decimals, or ends the line; the last such amount on a line is used. A number followed by % is a percentage.
  • Number formats: with both separators the last one is the decimal mark; "1,234" (comma + 3 digits) is read as a thousands separator in auto mode, "12,50" as a decimal; choose a fixed format to override.
  • Categories are assigned by ordered keyword rules (total → penalty → deposit → discount → tax → insurance/add-on → surcharge → fee → recurring → base). The first matching keyword is shown. Lines without any keyword default to base price.
  • Flags: conditional (late, cancellation, early termination, if, per day, wenn, falls, Verzug, pro Tag…), recurring (monthly, per year, subscription, monatlich…), optional/hidden (optional, pre-selected, recommended, auto-renew, empfohlen, voreingestellt…), included tax (incl./inkl./included).
  • Payable total = base + fees + taxes + surcharges + insurance/add-ons + recurring + discounts. Excluded: deposits (refundable), conditional lines (only if triggered), total lines, and taxes marked as included.
  • Percent-only lines: taxes are applied to the sum of all other included lines; other percentages are applied to the base total.
  • Non-base share = (payable total − base − discounts) ÷ payable total.

For scripts and AI agents

  • JSON API: POST https://hiddenfeefinder.usefulweb.site/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://hiddenfeefinder.usefulweb.site/mcp · tool name hidden_fee_finder
Example request
curl -s -X POST https://hiddenfeefinder.usefulweb.site/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{"currency":"USD","text":"Room rate, 3 nights: $420.00\nResort fee (mandatory): $105.00\nCity tax: 6%\nTravel insurance (pre-selected, optional): $29.99\nLate checkout fee if after 12:00: $50.00\nSecurity deposit (refundable): $200.00\nMember discount: -$21.00\nTotal: $566.03"}'
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