If a taxpayer had a spouse for only part of the income year, you may expect the Medicare Levy Surcharge (MLS) income threshold to be apportioned between the single and family thresholds.
However, this is not how the MLS threshold is determined.
How LodgeiT Calculates the MLS Threshold
LodgeiT follows the Australian Taxation Office (ATO) rules for calculating the Medicare Levy Surcharge.
For MLS purposes:
- If the taxpayer had a spouse for only part of the income year, the spouse's income is not included in the family income calculation.
- The family MLS income threshold only applies when the taxpayer had a spouse for the entire income year.
- As a result, LodgeiT applies the single MLS threshold for the income year in this scenario.
Example
Scenario
- Taxpayer became married or entered a de facto relationship on 11 August 2025.
- Prior to that date, the taxpayer was single.
Outcome
LodgeiT applies the single Medicare Levy Surcharge income threshold for the income year, as the taxpayer did not have a spouse for the full year.
Is the Threshold Apportioned?
No.
The Medicare Levy Surcharge threshold is not apportioned between the single and family thresholds based on the date the spouse was added.
Instead, the ATO rules determine whether the taxpayer qualifies to use the family threshold, and having a spouse for only part of the income year does not meet that requirement.
Reference
For more information, refer to the ATO guidance on the Medicare Levy Surcharge: Medicare levy surcharge – Paying the Medicare levy surcharge