electrical.electricity_bill

Three distinct suites: educational examples on the calculator page, this legacy regression count (21/21 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.3.1 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-13.trust-contract-ssr. Calculation version 1.3.1. CVP 1.0.0-proposed. 2/2 golden · 4/4 CVP boundary · 4/4 invalid · 5/5 property · 4/4 cross-interface · 4/4 CVP contract. digest 5343ac664b2f.

• Golden (oracle-backed) 2 / 2
• CVP boundary 4 / 4
• Invalid input 4 / 4
• Property 5 / 5
• Cross-interface 4 / 4
• CVP contract 4 / 4
• Interfaces PASS · UI (SSR) / REST / MCP
• Interface claim ui-ssr is query-result HTML, not a live browser session. Error-path engine·REST·MCP 1/1 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only. Public share URLs use UI ids (kwhInput/rateInput/prevInput/currInput). CVP-IFACE includes those serialized queries, not only canonical engine keys.
• Assurance Engineering

• release artifacts aligned PASS
• schema valid input executes PASS
• engine success output validates schema PASS
• schema rejects incomplete input PASS

Fingerprint sha256:f9e59b545171e8e6f6d181dd1fc997dbe94a639f4cd58adfc0fefd842396c396

Input schema sha256:8e57ad145969881ae2da285855f712bef698997f05f5855af3274f92b9737e57 · Output schema sha256:49a507d762717fa8939a7268df765f51b15e13725f6e4ba1f9e1952da789a2a3 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Tool

electricity

Engine

electricity-bill

Engine build

2026-09-12

Evidence core

2026-09-12T23:31:53.291Z

Rendered

2026-09-16T22:03:43.703Z

Last reviewed

2026-09-13

Assumptions

• Flat unit rate (no automatic slabs or TOU).
• Currency symbol is $ for display only; enter numeric values in your local currency. No FX conversion.
• Meter mode requires current ≥ previous on the same kWh register; otherwise METER_READING_DECREASED.
• Arithmetic is IEEE-754 binary64; only the displayed final amount is rounded to 2 decimal places.

Limitations

• Not for TOU / slab tariffs / export credits
• Current meter reading must be ≥ previous reading; otherwise METER_READING_DECREASED is returned
• Fee is a lump sum only; percentage and per-kWh taxes are not calculated