Editing and verifying a calculation

This page covers the two ideas at the heart of the tool: what a saved calculation actually is, and what the completeness check does - and does not - tell you. It is written for everyday taxpayers working through a modelo; for the step-by-step actions it links out to the how-to guides.

A calculation is a saved version, not a final answer

Each time you run a calculation, the tool saves that result as its own version and keeps the ones that came before. Nothing is overwritten. Tax work is rarely right the first time: you enter a figure, calculate, spot something off, correct it, and calculate again - and every attempt stays on disk, identified by its exact contents, so you can compare versions and go back. A saved version is a record of one attempt, not a verdict; its numbers commit to nothing until you decide they do. The mechanics live in The filing workflow.

A modelo is made of casillas (numbered boxes). Each box either holds a value or waits for one. Editing is the act of giving a box the value the form still needs, then recalculating so the totals reflect it - see Review and supply calculation inputs.

What verifying checks

Verifying runs a completeness check over a draft against the agency’s published rules for that modelo and year: every required box has a value, the sums add up with no box contradicting another, and nothing blocks the form - including conditions outside the draft itself, such as an earlier period this form builds on being filed and evidenced. The check saves a report whatever the result, and the draft lands in one of three states: complete (verified and locked), incomplete (required boxes still empty), or blocked (a failed rule or an unresolved dependency, named in the report). Running the check and acting on each finding is covered in Verify a draft filing.

A passed check is a local check: it means “my draft is complete and consistent”, never “AEAT accepted my filing”, “the upload will succeed”, or “I am on time” - the tool never contacts AEAT, and the check ignores deadlines entirely.

Why the tool wants a verified version before it builds the upload file

The upload file is the thing that leaves the tool and goes to the agency, so it is built only from a version that has passed the completeness check (or one already recorded as filed). The tool refuses a plain draft. The check is the gate a version has to clear before it can become a filing - protection against an incomplete draft being filed by accident.

Where this sits in the journey

This page is part of the how-it-works overview cluster. Earlier filings feed into later ones; for how a verified prior period carries forward, see How filings build on earlier ones. Once a version has passed the check, the next outputs are covered in Reviewing your numbers and producing the upload file.