Cap and Ring Size Conversion

Cap Sizes

Scroll down for ring sizes, gold guide, and other useful info.

American SizesMens Head Measurement in inchesLadies’ Head Measurement in inchesMetric Sizes
...48
6 1/8..49
6 1/4..50
6 3/820 1/219 1/251
6 1/220 5/82052
6 5/82120 1/253
6 3/421 1/22154
6 7/821 7/821 1/255
722 1/42256
7 1/822 5/822 1/857
7 1/4232358
7 3/823 3/823 1/259
7 1/223 3/42460
7 5/82424 1/261
7 3/424 1/22562
7 7/82525 1/263
825 1/22664

How do I know the right cap size ? 

Got a tape measure handy?

Measure your head with a tape measure, fitting it comfortably about one inch above your ears, or you can mark off a piece of string and measure it. Write it down for future reference. Use the chart that converts inches to hat sizes.

How do I find my ring size ? 

Most jewelry stores will size measure your ring size free of charge.Tee photo below can be printed and cut out and used to measure your size.Make sure when you print the ring sizer picture, you keep it its original size. Adult Hat Sizing Chart

XSSMLXLXXLXXXL
Size6 1/26 5/86 3/46 7/877 1/87 1/47 3/87 1/27 5/87 3/47 7/88
Inches20 1/220 3/421 1/821 1/221 7/822 1/422 5/82323 1/223 7/824 1/424 5/825
Metric52535455565758596061626364

Children’s Hat Sizing Chart

SizeSMLXL
Hat Size6 1/86 1/46 3/86 1/26 5/86 3/46 7/8
Inches19 1/819 1/22020 1/420 3/421 1/221 3/4
Metric49505152535455

Ring Sizes

InsideInsideInsideInsideNumber SizesWheat Sheaf  
DiameterDiameterCircumferenceCircumferenceUS/CanadaBritishJapaneseSwiss
(inches)(mm)(inches)(mm)StandardIrishEquivalentEquivalent
     Australian  
     Equivalent  
0.45811.61.43836.50   
0.46611.81.46337.21/4   
0.47412.01.48837.81/2A  
0.48212.21.51338.43/4A 1/2  
0.49012.41.53939.11B1 
0.49812.61.56439.71 1/4B 1/2  
0.50612.91.58940.41 1/2C  
0.51413.11.61441.01 3/4C 1/2  
0.52213.31.63941.62D21.50
0.53013.51.66442.32 1/4D 1/2  
0.53813.71.68942.92 1/2E32.75
0.54613.91.71443.52 3/4E 1/2  
0.55414.11.74044.23F44.00
0.56214.31.76544.83 1/4F 1/255.25
0.57014.51.79045.53 1/2G  
0.57814.71.81546.13 3/4G 1/266.50
0.58614.91.84046.747 
0.59415.11.86547.44 1/4H 1/2 7.75
0.60215.31.89048.04 1/28 
0.61015.51.91548.74 3/4J 9.00
0.61815.71.94149.35J 1/29 
0.62615.91.96649.95 1/4K 10.00
0.63416.11.99150.65 1/2K 1/210 
0.64216.32.01651.25 3/4L 11.75
0.65016.52.04151.86L 1/21112.75
0.65816.72.06652.56 1/412 
0.66616.92.09153.16 1/2M 1/21314.00
0.67417.12.11653.86 3/4N  
0.68217.32.14154.47N 1/21415.25
0.69017.52.16755.07 1/4  
0.69817.72.19255.77 1/2O 1/21516.50
0.70617.92.21756.37 3/4  
0.71418.12.24256.98P 1/21617.75
0.72218.32.26757.68 1/4  
0.73018.52.29258.28 1/2Q 1/217 
0.73818.72.31758.98 3/4R 19
0.74618.92.34259.59R 1/218 
0.75419.22.36860.19 1/4S 20.25
0.76219.42.39360.89 1/2S 1/219 
0.77019.62.41861.49 3/4T 21.5
0.77819.82.44362.110T 1/220 
0.78620.02.46862.710 1/4U21 
0.79420.22.49363.310 1/2U 1/22222.75
0.80220.42.51864.010 3/4V  
0.81020.62.54364.611V 1/223 
0.81820.82.56965.211 1/4W 25
0.82621.02.59465.911 1/2W 1/224 
0.83421.22.61966.511 3/4X  
0.84221.42.64467.212X 1/22527.50
0.85021.62.66967.812 1/4  
0.85821.82.69468.412 1/2Z2628.75
0.86622.02.71969.112 3/4Z 1/2  
0.87422.22.74469.713 27 
0.88222.42.76970.313 1/4Z1  
0.89022.62.79571.013 1/2   
0.89822.82.82071.613 3/4Z2  
0.90623.02.84572.314Z3  
0.91423.22.87072.914 1/4   
0.92223.42.89573.514 1/2Z4  
0.93023.62.92074.214 3/4   
0.93823.82.94574.815   
0.94624.02.97075.415 1/4   
0.95424.22.99676.115 1/2   
0.96224.43.02176.715 3/4   
0.97024.63.04677.416   
Karat GoldParts GoldPercentage GoldNormal European Stamping
9 kt9 in 2437.50%375
10 kt10 in 2441.67%416
12 kt12 in 2450%500
14 kt14 in 2458.33%583 or 585
18 kt18 in 2475%750
22 kt22 in 2491.67%917
24 kt24 in 2499.99%999 or .99999
Gold has a density of 19.32 g/cm3, silver has a density of only 10.49 g/cm3

GOLD KARAT INFORMATION CHART

Gold (K= karat) (P= Plum) Plum is high quality (purity) when a P is added. (example 18KP)

10K……41.7%pure

12K……50% pure

14K……58.3% pure

18K……75% pure

22K……91.2% pure

24K……99.9% pure

Gold Filled Markings (W1/20 14K G.F.) what it means: W=weight,

1/20 = 5% gold, G.F. = Gold Filled. Gold Filled is 300 times thicker than gold plating. Gold filled is bonded to brass or bronze with (fusing) heat & pressure. By law 5% of its total weight must be gold.

Gold Plating: Thin coating of gold over a base metal (Electroplating) A gold plated item will be marked 18K or 14K HGE (Heavy Gold Electroplating) Gold plating is 7 – 100 millionths of an inch thick.

Silver:

Sterling is 92.5% silver, 7.5% copper

Sterling Markings are .925, STER, STERLING.

Sterling from England are marked by a Lion Hallmark.

Silver Filled items are marked 1/20 silver filled.

Vermeil is sterling silver covered by an electroplating of gold.

Platinum:

Markings are PLAT, or PLATINUM, and maybe marked .900 or .950

Troy Pound (0.37kg) A mass unit is used to measure precious metals. There are 12 troy ounces in every troy pound. One troy pound is equal to 373 grams.

Troy Ounce The traditional unit of weight for precious metals and gems. 1 troy ounce = 480 grains 1 troy ounce = 24 scruples 1 troy ounce = 20 pennyweights (North American jewelery trade) 1 troy ounce = 1.097 ordinary ounce 1 troy ounce = 8 drams 1 troy ounce = 31.1034768 grams. 1 troy ounce = 120 carats 1 troy ounce = 155.52 metric carats (diamonds / precious stones). 3.75 troy ounces = 10 tolas (Indian sub-continent) 6.02 troy ounces = 5 taels (Hong Kong) 12 troy ounce=1 troy pound 14.583 troy ounce =16 avoirdupois ounce (1Pound) 32.15 troy ounces = 1 kilogramme (Kilo) 32,150 troy ounces = 1 metric ton (1,000 kilos) 1000 troy ounces = 31.1 kilograms Pennyweight (dwt): The pennyweight was the weight of a silver penny in medieval England. It is no coincidence that there were 240 pennies to the English pound. 240 silver pennies were equivalent to a pound of silver. The word sterling applies both to the English pound and to the standard purity of silver. 1 pennyweight = 24 grains (dwt) (1 old time French penny) 1.55 grams=1 pennyweight (dwt) 20 dwt=1 troy ounce 240 pennyweights = 1 pound troy 24 grains=1 dwt 1 pennyweight =.05 troy ounce 1 gram=.643 pennyweight Gram 1 gram =.03215 troy ounce 1 gram =.643 pennyweight 1.555 grams = 1 pennyweight (dwt) 1 gram =0.00267923 apothecary or troy pound 1 gram =0.00220462 avoirdupois pound 1 gram =0.0321507 apothecary or troy ounce 1 gram =0.564383 avoirdupois dram 1 gram =0.257206 apothecary or troy dram 1 gram =0.6430149 pennyweight 1 gram =0.771618 scruple 1 gram =15.4324 grains 1 gram =1×10^-6 metric ton 1 gram =1×10^-4 myriagram 1 gram =0.001 kilogram 1 gram =5 metric carats 1 gram =1000 milligrams 1 gram =1×10^6 microgram 1 Gram = 5 Carats Gram-Calorie (mean) Gram-Calorie (mean) =1.5593×10^-6 horse power hours Gram-Calorie (mean) =0.001 kilogram calorie Gram-Calorie (mean) = 0.0011628 watt-hour Gram-Calorie (mean) =0.001459 cubic foot atmosphere Gram-Calorie (mean) =0.0039685 BTU (mean) Gram-Calorie (mean) =0.0039685 BTU (mean) Gram-Calorie (mean) =0.041311 liter-atmosphere Gram-Calorie (mean) =0.42685 kilogram-meter Gram-Calorie (mean) =3.0874 foot-pounds Gram-Calorie (mean) =4.186 joules (absolute) Gram-Calorie (mean) =99.334 foot-poundals Gram-calorie (15°C) = 4.185 joules (absolute). Gram-calorie (20°C) = 4.181 joules (absolute). Gram-centimeter =2.3427×10^-8 kilogram-calorie (mean) Gram-centimeter =9.2972×10^-8 BTU (mean) Gram-centimeter =1×10^-5 kilogram-meter Gram-centimeter =2.3427×10^-5 gram-calorie (mean) Gram-centimeter =7.233×10^-5 foot-pound Gram-centimeter =9.80665×10^-5 joule (absolute) Gram-centimeter =980.7 ergs

Grain: An ancient unit which was originally based on the weight of a grain of wheat. The grain is the smallest unit of weight in the avoirdupois, troy, and apothecaries systems. Surprisingly it is identical in all three systems. 1 grain = 64.8 milligrams 1 grain = 0.0648 grams 4 grains = 1 carat 15.432 grains = 1 gram 20 grains = 1 scruple 24 grains =1 pennyweight 480 grains = 1 troy ounce 5760 grains = 1 troy pound 437.5 grains = 1 ounce avoirdupois 7000 grains = 1 pound avoirdupois Grain = 1/7000 avoirdupois pound Grain = 1/5760 apothecary or troy pound Grain = 0.0022857 avoirdupois ounce Grain = 0.0020833 apothecary or troy ounce Grain = 0.03657143 avoirdupois dram Grain = 0.016667 apothecary or troy dram Grain = 0.0416667 troy pennyweight Grain = 0.05000 apothecary scruple Grain =0.064798918 gram Grain =0.3240 metric carat Grain =64.798918 milligram

Dram or Drachm An ancient unit of weight, also a Greek coin. It is believed to have originally meant the amount which one could hold in one’s hand. 16 drams = 1 ounce avoirdupois 8 drams = 1 ounce apothecaries 1 drams = 27.34375 grains 1 dram = 1.772 grams 3 scruples = 1 drachm 20 grains = 1 scruple

Momme A unit of weight previously used in Japan to weigh pearls. 75 grains = momme 18.75 carats = 1 momme 3.75 grams = 1 momme Imperial System A British system developed and refined from the earlier Roman systems used in Britain during the middle ages. Kevin Loughrey from Non Volatile Technologies Pty Ltd contributed some corrections below. 20 cwt = 1 ton (40 bushells or 160 stones) = 1 ton avoirdupois 4 stones = 1 bushell (56lbs) 1 hundredweight (cwt) = 112lbs (2 bushells, or 8 stones) 14 pounds avoirdupois = 1 stone avoirdupois 16 ounces avoirdupois = 1 pound avoirdupois 1 ounce avoirdupois = 28.349523 grams approx. 1 pound avoirdupois = 453.59237 grams 1 ton avoirdupois = 2240 pounds avoirdupois

Conversion Formulas Use these formulas to convert! Carats to Dwt x by .12860 Carats to Grams x by .2 Dwt to Carats x by 7.776 Dwt to Grams x by 1.5552 Dwt to Troy oz x by .05 Grams to Carats x by 5.0 Grams to Dwt x by .64301 Avoir Oz to Troy oz x by .91146 Avoir Oz to Grams x by 28.3495 Troy Oz to Avoir oz x by 1.091

Convert fractions to decimals and millimeters and reverse. (1 INCH = 25.4 MM EXACTLY)

fractiondecimalmmfractiondecimalmmfractiondecimalmm
1/640.01560.39691 1/641.015625.79692 1/642.015651.1969
1/320.03130.79381 1/321.031326.19382 1/322.031351.5938
3/640.04691.19061 3/641.046926.59062 3/642.046951.9906
1/160.06251.58751 1/161.062526.98752 1/162.062552.3875
5/640.07811.98441 5/641.078127.38442 5/642.078152.7844
3/320.09382.38131 3/321.093827.78132 3/322.093853.1813
7/640.10942.77811 7/641.109428.17812 7/642.109453.5781
1/80.12503.17501 1/81.125028.57502 1/82.125053.9750
9/640.14063.57191 9/641.140628.97192 9/642.140654.3719
5/320.15633.96881 5/321.156329.36882 5/322.156354.7688
11/640.17194.36561 11/641.171929.76562 11/642.171955.1656
3/160.18754.76251 3/161.187530.16252 3/162.187555.5625
13/640.20315.15941 13/641.203130.55942 13/642.203155.9594
7/320.21885.55631 7/321.218830.95632 7/322.218856.3563
15/640.23445.95311 15/641.234431.35312 15/642.234456.7531
1/40.25006.35001 1/41.250031.75002 1/42.250057.1500
17/640.26566.74691 17/641.265632.14692 17/642.265657.5469
9/320.28137.14381 9/321.281332.54382 9/322.281357.9438
19/640.29697.54061 19/641.296932.94062 19/642.296958.3406
5/160.31257.93751 5/161.312533.33752 5/162.312558.7375
21/640.32818.33441 21/641.328133.73442 21/642.328159.1344
11/320.34388.73131 11/321.343834.13132 11/322.343859.5313
23/640.35949.12811 23/641.359434.52812 23/642.359459.9281
3/80.37509.52501 3/81.375034.92502 3/82.375060.3250
25/640.39069.92191 25/641.390635.32192 25/642.390660.7219
13/320.406310.31881 13/321.406335.71882 13/322.406361.1188
27/640.421910.71561 27/641.421936.11562 27/642.421961.5156
7/160.437511.11251 7/161.437536.51252 7/162.437561.9125
29/640.453111.50941 29/641.453136.90942 29/642.453162.3094
15/320.468811.90631 15/321.468837.30632 15/322.468862.7063
31/640.484412.30311 31/641.484437.70312 31/642.484463.1031
1/20.500012.70001 1/21.500038.10002 1/22.500063.5000
33/640.515613.09691 33/641.515638.49692 33/642.515663.8969
17/320.531313.49381 17/321.531338.89382 17/322.531364.2938
35/640.546913.89061 35/641.546939.29062 35/642.546964.6906
9/160.562514.28751 9/161.562539.68752 9/162.562565.0875
37/640.578114.68441 37/641.578140.08442 37/642.578165.4844
19/320.593815.08131 19/321.593840.48132 19/322.593865.8813
39/640.609415.47811 39/641.609440.87812 39/642.609466.2781
5/80.625015.87501 5/81.625041.27502 5/82.625066.6750
41/640.640616.27191 41/641.640641.67192 41/642.640667.0719
21/320.656316.66881 21/321.656342.06882 21/322.656367.4688
43/640.671917.06561 43/641.671942.46562 43/642.671967.8656
11/160.687517.46251 11/161.687542.86252 11/162.687568.2625
45/640.703117.85941 45/641.703143.25942 45/642.703168.6594
23/320.718818.25631 23/321.718843.65632 23/322.718869.0563
47/640.734418.65311 47/641.734444.05312 47/642.734469.4531
3/40.750019.05001 3/41.750044.45002 3/42.750069.8500
49/640.765619.44691 49/641.765644.84692 49/642.765670.2469
25/320.781319.84381 25/321.781345.24382 25/322.781370.6438
51/640.796920.24061 51/641.796945.64062 51/642.796971.0406
13/160.812520.63751 13/161.812546.03752 13/162.812571.4375
53/640.828121.03441 53/641.828146.43442 53/642.828171.8344
27/320.843821.43131 27/321.843846.83132 27/322.843872.2313
55/640.859421.82811 55/641.859447.22812 55/642.859472.6281
7/80.875022.22501 7/81.875047.62502 7/82.875073.0250
57/640.890622.62191 57/641.890648.02192 57/642.890673.4219
29/320.906323.01881 29/321.906348.41882 29/322.906373.8188
59/640.921923.41561 59/641.921948.81562 59/642.921974.2156
15/160.937523.81251 15/161.937549.21252 15/162.937574.6125
61/640.953124.20941 61/641.953149.60942 61/642.953175.0094
31/320.968824.60631 31/321.968850.00632 31/322.968875.4063
63/640.984425.00311 63/641.984450.40312 63/642.984475.8031
11.000025.400022.000050.800033.000076.2000

MORE USEFUL CONVERSIONS To convert decimal fractions of an inch to fractions of an inch. Take the decimal fraction of feet and divide by 0.08333 (1/12th) and this will give you inches and decimals of an inch. For example – 6.37 feet. Take the 0.37 feet and divide by 0.0833 = 4.44 inches . So for 6.37 ft. we can also say 6 ft. –  4.44 in. Now take the 0.44 in. and round it down to 0.4 which is 4/10″ We can now say 6.37′ approximatly equals 6′ – 4 4/10″ For fractions of an inch other than tenth’s, take the decimal remainder of inches and divide by: 0.125 for the number of eighth’s 0.0625 for the number of sixteenth’s 0.03125 for the number of thirty-second’s 0.015625 for the number of sixty-fourth’s, and so on. For example – 4.382 inches. For eighth’s, divide the remainder, 0.382 by 0.125 and the answer is 3.056 so the fraction is a bit over 3 eighth’s, therefore the answer ends up as approx. 4 3/8″