You drove your own car to a client site or a branch office, and now the expense form wants a number for fuel. Do you attach the gas station receipt? Use one-way or round-trip distance? Today's pump price or an average? Your dashboard's fuel economy or some official figure? In Korea, the answer depends on who pays you. Public institutions follow the national travel expense regulation, while private companies follow their own internal rules (사규, sagyu), and the two rarely match. If you are a foreign employee, there is one more layer: the tax treatment of car allowances can change depending on which income tax option you chose. This guide starts with the numbers for a 240 km round trip, then explains the rules behind them.
1. How Much Is a 240 km Round Trip? Worked Numbers First
When fuel is reimbursed at actual cost, almost every Korean employer uses the same formula:
Fuel cost = distance (km) x fuel price (KRW/L) / fuel economy (km/L)
The examples below assume a 120 km one-way trip (240 km round trip). Fuel prices are illustrative assumptions (gasoline KRW 1,650, diesel KRW 1,550, LPG KRW 1,050 per liter). For a real claim, use the average price published on Opinet (오피넷), the Korea National Oil Corporation's fuel price site, for the day the trip started. Amounts are rounded down to the won.
| Fuel type | Assumed price | Fuel economy applied | 240 km round trip |
|---|---|---|---|
| Gasoline | KRW 1,650/L | 11.97 km/L | KRW 33,082 |
| Diesel | KRW 1,550/L | 12.52 km/L | KRW 29,712 |
| LPG | KRW 1,050/L | 8.83 km/L | KRW 28,539 |
| Hybrid | KRW 1,650/L | 15.37 km/L | KRW 25,764 |
| Electric | KRW 340/kWh (fast-charge assumption) | 5.22 km/kWh | KRW 15,632 |
The fuel economy figures are the per-fuel-type values widely cited from the 2023 revision of the government's travel expense processing standards. Many private companies without their own figures borrow them as a reference. The standards are reissued each year by the Ministry of Personnel Management, so confirm the current version with your accounting team before you submit.
The same 240 km under different company policies
| Company method | Calculation | Claim |
|---|---|---|
| Flat KRW 250 per km | 240 km x 250 | KRW 60,000 |
| Flat KRW 300 per km | 240 km x 300 | KRW 72,000 |
| Actual cost, rated 14 km/L | 240 x 1,650 / 14 | KRW 28,285 |
| Actual cost, real-world 10 km/L | 240 x 1,650 / 10 | KRW 39,600 |
Per-km rates are higher because they are meant to cover more than fuel: tires, oil changes, depreciation, and insurance for using your personal car on company business. Actual-cost methods return only the fuel, but they rise automatically when prices go up.
2. Public-Sector Rules: In-Area vs Out-of-Area Trips
If you work for a Korean public institution, a university, or a company that copies government rules, the key distinction is between trips inside your work area (근무지 내, geunmuji nae) and trips outside it (근무지 외, geunmuji oe). The basis is the Regulation on Travel Expenses for Public Officials (공무원 여비 규정), Articles 16 and 18 and Annex 2.
| Item | In-area trip | Out-of-area trip |
|---|---|---|
| Scope | Same city, county, or island, or under 12 km round trip | Anything beyond the in-area scope |
| Payment | Flat rate | Fare (actual cost) + daily allowance + meals + lodging |
| Amount | KRW 20,000 for 4+ hours, KRW 10,000 under 4 hours | Daily allowance and meals KRW 25,000 each |
| Private car fuel | Included in the flat rate | Fuel and tolls payable when there is an unavoidable reason |
| Reductions | KRW 10,000 less with an official vehicle | Daily allowance halved with an official vehicle |
For out-of-area trips, the default rule is that private car travel is reimbursed at the equivalent rail or bus fare. Fuel and tolls are paid only when the car was genuinely necessary: remote areas without public transport, heavy equipment, late-night or urgent travel, or a route too complex for buses and trains. Fuel is then calculated with the formula above, using the Opinet average price on the start date and the per-fuel-type standard economy. For electric cars, the ministry's guidance is to use the fast-charging rate posted on the Ministry of Environment's zero-emission vehicle portal.
A one-day out-of-area trip in a gasoline car with KRW 9,600 in round-trip tolls (assumed) adds up to KRW 92,682: fuel 33,082 + tolls 9,600 + daily allowance 25,000 + meals 25,000. Note that a destination over 12 km away in another city can still be treated as in-area if it is reachable by subway or shuttle bus, at the head of the institution's discretion.
3. Company Policies and the Car Allowance Trap
Private companies have no single legal formula. Most internal rules use one of three approaches:
- Per-km flat rate: distance x a fixed rate. Simple and common in small and mid-sized firms.
- Actual cost: distance x Opinet price / rated or standard fuel economy.
- Receipt-based: the fuel receipts from the trip period, increasingly replaced by distance-based methods because personal driving gets mixed in.
Many employees also receive a monthly car allowance (자가운전보조금, jaga unjeon bojogeum). Under Korea's Income Tax Act Enforcement Decree, up to KRW 200,000 per month is tax-free when you drive a car you own or lease in your own name for company work and receive the allowance in place of actual travel expenses. That "in place of" condition matters: if you are also reimbursed for actual fuel on the same trips, the tax-free treatment of the allowance can be denied. Settle with payroll which method applies to you.
4. What Changes for Foreign Employees in Korea
The fuel formula itself is the same regardless of nationality or visa. What can differ is the tax side.
- Flat 19% tax option: Foreign employees (excluding daily workers) who started work in Korea on or before December 31, 2026 may elect to pay income tax at a flat 19% of employment income for up to 20 years from their first day of work, under the Restriction of Special Taxation Act Article 18-2. With local income tax (10% of income tax), the effective rate is 20.9%.
- Tax-free items do not apply under the flat rate: If you choose the 19% option, income tax exemptions, deductions, and credits are not applied, apart from certain welfare-related exemptions set by decree. In practice, this means a monthly car allowance that would be tax-free for someone on the regular system may be counted in your taxable pay. Ask payroll how your allowance and any fuel reimbursements are handled before deciding between a monthly allowance and per-trip actual-cost claims.
- You must apply for it: The flat rate is not automatic. Your employer withholds 19% monthly only after you apply.
Tax rules depend on your residency status, visa, and individual circumstances. Check with your employer's payroll team or the National Tax Service (126) before relying on any of these figures.
5. Receipts and Proof to Keep
| Proof | What to capture | Why |
|---|---|---|
| Opinet price screen | Average price on the trip start date | Basis for the price in the formula |
| Route distance screenshot | Standard route distance in a map app | Distance is calculated on the usual route |
| Odometer photos | Readings at departure and return | Confirms actual driving |
| Toll records | Hi-Pass history or receipts | Toll reimbursement |
| Parking and fuel receipts | Parking at the destination, etc. | Proves the car was used |
Travel expenses are calculated on the usual route and method, so your distance claim should match a map app's standard route rather than any detour you took. Since the 2023 revision, photos taken at the site can serve as evidence when receipts are impossible to obtain, such as in remote areas.
Common mistakes: entering one-way distance for a round trip (a 120 km one-way figure halves the claim to KRW 16,541), using your own dashboard fuel economy instead of the standard figure, using a single station's receipt price instead of the average, and claiming a fare for passengers. When two or more people travel together for the same purpose, one car is the rule and passengers receive no separate fare.
6. Frequently Asked Questions
Q1. Should I enter one-way or round-trip distance?
Enter the total distance actually traveled for the trip. For a same-day trip, that is the round trip. If you stayed overnight and returned another day, add the outbound and return legs.
Q2. Which fuel price should I use?
The government standard uses the Opinet average price on the trip start date. Whether that is a regional or national average can vary by institution, so follow your internal guideline. If your company has no rule, the Opinet regional average is the safest choice.
Q3. My car's real fuel economy is worse than the standard. Can I claim more?
Generally no. Public institutions apply the standard figure by fuel type, and companies apply whatever their rules specify. Your dashboard reading is useful for checking whether a per-km rate covers your real costs, but it is not usually the basis for the claim.
Q4. I'm used to miles and gallons. How do I convert?
Convert distance to kilometers and mpg to km/L first, then apply the formula. One US mpg equals about 0.425 km/L, so 30 mpg is roughly 12.8 km/L.
7. Calculate Your Trip's Fuel Cost in Seconds
You do not need to work the formula by hand. Open the Trip cost tab in the Fuel Economy Calculator, enter the one-way distance, the fuel economy your rules require, and the start-date fuel price, then tick "Round trip." You get the total distance, fuel needed, estimated cost, and cost per km, which makes it easy to compare your company's per-km rate with what the fuel actually cost.
If your rental car abroad shows mpg or miles, convert them in the Unit Converter first. For background on metric and imperial units, see the unit conversion guide.
Figures in this guide are based on the Regulation on Travel Expenses for Public Officials and the 2023 revised processing standards. Standards may be updated annually, so confirm the latest rules with your institution or employer before submitting a claim.
