$40K in Rapid City = $22,727 in Koh Samui
Your $40K salary in Rapid City (COL 88) has the same purchasing power as $22,727 in Koh Samui (COL 50). Koh Samui is cheaper — your money goes 43% further there.
Budget breakdown — $40K in both cities
What $40K actually buys you in each city after taxes and core expenses.
| Expense | Rapid City $40K | Koh Samui $40K (same salary) |
|---|---|---|
| Monthly take-home | $2,728 | $2,728 |
| 1BR rent | $1,200 | $620 |
| Groceries | $365 | $380 |
| Transport | $40 | $150 |
| Utilities | $148 | $70 |
| Internet | $65 | $28 |
| Left after essentials | $910/month | $1,480/month |
Frequently asked questions
What is $40K in Rapid City equivalent to in Koh Samui?
$40K in Rapid City (COL index 88) has the same purchasing power as $22,727 in Koh Samui (COL index 50). That's 43% less than your current salary.
If I move from Rapid City to Koh Samui keeping my $40K salary, will I be better off?
Yes. If you keep earning $40K after moving to Koh Samui, you'd have $570 more per month after core expenses — because Koh Samui is cheaper than Rapid City.
How is the salary equivalent calculated?
The equivalent salary is calculated by multiplying your current salary by the ratio of the two cities' overall cost of living indices: $40K × (50 ÷ 88) = $22,727. This adjusts for differences in housing, food, transport, and general cost of living.
Other salary amounts — Rapid City to Koh Samui
Equivalency uses overall COL index ratio. Take-home uses simplified federal/state brackets. Zillow · BLS · Numbeo · Q1 2026 · For general guidance only