Verified April 2026
How to Calculate Sales Tax in Kauai, Hawaii
2026 Step-by-Step Guide for Businesses & Consumers
Current Kauai Sales Tax Rate
| Jurisdiction | Rate |
|---|---|
| Hawaii State Sales Tax | 4.000% |
| County Sales Tax | 0.500% |
| Total Combined Rate | 4.500% |
How to Calculate Sales Tax in Kauai
-
1
Find the combined rate
The combined sales tax rate in Kauai is 4.500%. This equals: Hawaii state rate of 4.000% + County 0.500%.
-
2
Convert the percentage to a decimal
4.500 ÷ 100 = 0.0450
-
3
Multiply by your purchase amount
Example: $100.00 × 0.0450 = $4.50 in sales tax
-
4
Add tax to the original price
$100.00 + $4.50 = $104.50 total cost
What's Taxable in Hawaii?
Most tangible personal property is taxable in Hawaii. Check with the
Hawaii Department of Revenue for specific exemption categories.
Do You Have Nexus in Hawaii?
Economic Nexus Threshold
If your business has over $100,000 in annual
Hawaii sales or 200 transactions,
you are required to collect and remit Hawaii sales tax. This applies to out-of-state remote sellers too.
Expert Sales Tax Tips for Kauai
Out-of-State Sellers
Selling into Hawaii from out of state? Register before you cross the $100,000 threshold to avoid back taxes and penalties.
Frequently Asked Questions
Sales Tax Calculator
Using 4.500% rate for Kauai
$
Tax Amount
$0.00
Total with Tax
$100.00
Rate applied: 4.500% combined