## TL;DR

The claimed per-diem days extend beyond (or fall short of) the booked travel dates, so the system cannot validate the allowance. Pull the actual itinerary (flight and hotel confirmations), correct the claim's start and end dates to match, and resubmit. Partial travel days are usually paid at a reduced rate per policy, not excluded.

## Error

```text
per diem claim failed: travel dates don't match the itinerary
```

## Steps

1. Open the rejected per-diem claim and note the claimed date range. Expected: you see the start and end dates the claim covers.
2. Pull the actual itinerary: flight confirmations and hotel check-in and check-out dates. Expected: you have the authoritative travel dates.
3. Correct the claim dates to match the itinerary, applying the policy's partial-day rules for travel days. Expected: the claimed days align with actual travel.
4. If the trip genuinely extended beyond the booking (e.g. a rebooked return), attach the rebooking confirmation. Expected: the extension is documented.
5. Resubmit the claim. Expected: the date validation passes and the allowance computes.

## When to use

- A per-diem claim fails on travel-date mismatch.
- The itinerary changed mid-trip and the claim was not updated.
- Partial travel days were claimed as full days.

## When not to use

- The destination has no per-diem rate (a rate-table problem).
- The daily rate itself is disputed.
- The trip was canceled and no travel occurred.

## Tool compatibility

Applies across expense tools with per-diem support (Rydoo, Concur, Expensify, and others; current 2026 releases).

### Variant phrasings

### per diem "dates outside itinerary" error

Same mismatch in alternate wording. Align the claim to the bookings.

### trip extended and per diem rejected

The claim covers days with no booking. Document the extension.

### partial travel day claimed as full day

Policy usually pays a fraction for travel days. Apply the partial-day rule.

## Why it happens

Per-diem validation cross-checks claimed days against booked travel because the allowance is meant to cover days actually away. Mismatches come from stale claims (itinerary changed after the claim was drafted), optimistic date entry, or misunderstanding partial-day rules. The check protects against paying allowances for days not traveled, which is why documentation of genuine extensions clears it.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_9SErkKPhOVCrGZ7zrZgPaA