Oil Change Interval Calculator公式

## Oil Change Scheduling

Modern synthetic oils and engines allow longer intervals than the old 3,000-mile rule, but severe driving conditions require more frequent changes.

### Formula

**Effective Interval = Base Interval x (1 - 0.4 if severe conditions)**

**Next Change = Last Change Mileage + Effective Interval**

Severe conditions include frequent short trips, dusty roads, heavy towing, extreme temperatures, and stop-and-go traffic. Most modern cars with synthetic oil recommend 7,500-10,000 mile intervals under normal conditions.

计算示例

Last change at 38,000 miles, now at 45,000, 7,500-mile interval, normal conditions.

  1. Effective interval = 7,500 x (1 - 0) = 7,500 miles
  2. Next change = 38,000 + 7,500 = 45,500 miles
  3. Miles remaining = 7,500 - 7,000 = 500 miles
  4. Oil life = (1 - 7000/7500) x 100 = 6.7%