A method and apparatus is disclosed for voltage-controlled oscillator selection in a multi-mode system having multiple voltage-controlled oscillators. Part of oscillator selection is a calibration operation that utilizes maximum and minimum capacitance limits for a voltage-controlled oscillator, which translates to a frequency range, to calculate overlap regions. Overlap regions comprise frequency ranges that overlap such that the overlap region may be generated by two voltage-controlled oscillators with adjacent frequency ranges. One voltage-controlled oscillator selection routine comprises a real time voltage-controlled oscillator calibration and selection routine that executes every time the system requests a new frequency. Another selection routine comprises a start-up routine that executes only at power up or periodically. Another selection routine comprises a successive voltage-controlled oscillator routine that executes every time a frequency is requested by comparing a requested frequency to different frequency thresholds without executing a calibration operation.