Compatibility summary
Your Spain plug may fit in Bhutan outlets, as both use at least one common plug type.
Plug comparison
Spain plug types: C F
Bhutan plug types: C D M
Both countries share at least one plug type (C F and C D M), so some plugs may work without an adapter. Check your appliance.
Voltage comparison
Spain: 230V, 50Hz
Bhutan: 230V, 50Hz
Voltage difference is within a range many devices tolerate; check your appliance label.