If someone is unsure about their zakat calculation due to financial complexity, they should:

1. **Seek Guidance from Scholars**: Consult a knowledgeable Islamic scholar or an expert in Islamic finance.

2. **Use Zakat Calculators**: Utilize reputable online zakat calculators that take various factors into account.

3. **Review Financial Records**: Carefully examine all assets, liabilities, and eligible zakat items.

4. **Err on the Side of Caution**: If uncertain, it is recommended to give more rather than less to fulfill the obligation adequately.

These steps help ensure that zakat is calculated and paid correctly according to Islamic teachings.