E6 series: 6 values per decade, ±20% tolerance. Common for electrolytics.
E12 series: 12 values per decade, ±10% tolerance. Common for ceramic/film caps.
E24 series: 24 values per decade, ±5% tolerance. Precision film capacitors.
Standard Capacitor Values is a free online calculator tool. Use it to get instant, accurate results for your electronics calculations.