For capacitor values expressed like this: 100 121 152 223 337 etc., all capacitances are in pF. where, The first two digits are the **Mantissa** value and are read simply as decimal numbers so: 10 = ten; 12 = twelve; 15 = fifteen; 22 = twenty two; 33 = thirty three; The 3rd digit is the **Exponent** (power of 10) and is read as "times ten to the power of" so: 10**0** = ten times ten to the power of **0** = 10 x 1 = 10pF; example: http://uk.farnell.com/tdk/c1608c0g1h100d080aa/cap-mlcc-c0g-np0-10pf-50v-0603/dp/2309035 12**1** = twelve times ten to the power of **1** = 12 x 10 = 120pF; example: http://uk.farnell.com/yageo-phycomp/cc0603jrnpo9bn121/cap-mlcc-c0g-np0-120pf-50v-0603/dp/722091 15**2** = fifteen times ten to the power of **2** = 15 x 100 = 1500pF = 1.5nF; example: http://uk.farnell.com/multicomp/mc0603b152k500ct/cap-mlcc-x7r-1-5nf-50v-0603/dp/1759091 22**3** = twenty two times ten to the power of **3** = 22 x 1000 = 22000pF = 22nF; example: http://uk.farnell.com/walsin/0603b223k500ct/capacitor-mlcc-x7r-0-022uf-50v/dp/2496847 33**7** = thirty three times ten to the power of **7** = 33 x 1e7 = 330,000,000pF = 330uF example: http://uk.farnell.com/murata/grm32er60g337me05l/cap-mlcc-x5r-330uf-4v-1210/dp/2671593 * For capacitances < 10pF the value is usually expressed as "4R7" = 4.7pF or "0R5" = 0.5pF. example: http://uk.farnell.com/walsin/0402n4r7c500ct/cap-mlcc-np0-4-7pf-50v-0402-reel/dp/2524790 example: http://uk.farnell.com/multicomp/mc0402n0r5c500ct/cap-mlcc-c0g-np0-0-5pf-50v-0402/dp/1758929 (This is the same as for resistors of < 10 Ohms.) In some, the leading 0 maybe omitted. example: http://uk.farnell.com/kemet/c0603c479c5gactu/cap-mlcc-c0g-np0-4-7pf-50v-0603/dp/1414645 example: http://uk.farnell.com/yageo-phycomp/cc0603crnpo9bnr68/cap-mlcc-c0g-np0-0-68pf-50v-0603/dp/721827 * Note that in some, the exponent of 8 or 9 may be used but is interpreted as 8 = 10 to the power -1 = 0.01 9 = 10 to the power -2 = 0.1 so 479 = 47 x 0.1 = 4.7pF example: http://uk.farnell.com/kemet/c0603c479c5gactu/cap-mlcc-c0g-np0-4-7pf-50v-0603/dp/1414645 Note that for this particular capacitor it is unclear if the leading zero is missing from 0R47 to be read as "R47" or if a trailing 9 has been used to be read as "479". :)