Resistors - Prefered  Values

There are 2 main series of preferred resistor values, E12 (12 values per decade) and E24 (24 values per decade). It is useful to know them when designing circuits since you will only be able to buy resistors in those values. Generally carbon 5% resistors are available in E12 series and metal film 1% resistors are available in E24 series.

E12 Series
1R0 10R 100R 1K0 10K 100K 1M0 10M
1R2 12R 120R 1K2 12K 120K 1M2  
1R5 15R 150R 1K5 15K 150K 1M5  
1R8 18R 180R 1K8 18K 180K 1M8  
2R2 22R 220R 2K2 22K 220K 2M2  
2R7 27R 270R 2K7 27K 270K 2M7  
3R3 33R 330R 3K3 33K 330K 3M3  
3R9 39R 390R 3K9 39K 390K 3M9  
4R7 47R 470R 4K7 47K 470K 4M7  
5R6 56R 560R 5K6 56K 560K 5M6  
6R8 68R 680R 6K8 68K 680K 6M8  
8R2 82R 820R 8K2 82K 820K 8M2  

E24 Series
1R0 10R 100R 1K0 10K 100K 1M0 10M
1R1 11R 110R 1K1 11K 110K 1M1  
1R2 12R 120R 1K2 12K 120K 1M2  
1R3 13R 130R 1K3 13K 130K 1M3  
1R5 15R 150R 1K5 15K 150K 1M5  
1R6 16R 160R 1K6 16K 160K 1M6  
1R8 18R 180R 1K8 18K 180K 1M8  
2R0 20R 200R 2K0 20K 200K 2M0  
2R2 22R 220R 2K2 22K 220K 2M2  
2R4 24R 240R 2K4 24K 240K 2M4  
2R7 27R 270R 2K7 27K 270K 2M7  
3R0 30R 300R 3K0 30K 300K 3M0  
3R3 33R 330R 3K3 33K 330K 3M3  
3R6 36R 360R 3K6 36K 360K 3M6  
3R9 39R 390R 3K9 39K 390K 3M9  
4R3 43R 430R 4K3 43K 430K 4M3  
4R7 47R 470R 4K7 47K 470K 4M7  
5R1 51R 510R 5K1 51K 510K 5M1  
5R6 56R 560R 5K6 56K 560K 5M6  
6R2 62R 620R 6K2 62K 620K 6M2  
6R8 68R 680R 6K8 68K 680K 6M8  
7R5 75R 750R 7K5 75K 750K 7M5  
8R2 82R 820R 8K2 82K 820K 8M2  
9R1 91R 910R 9K1 91K 910K 9M1  

I came across a modern electronic hobbyist magazine that listed values of 50K and 40K for fixed resistors. I let them know in a nice way that it was pretty stupid of them to use non-standard values. The article was probably written by some clown that did everything on computer and never actually built the circuit, the computer program not have the smarts to use standard values.

By the way, I have the standard values of 20%, 10% and 5% resistors memorized, not because I set out to memorize them, but simply because after 40+ years of messing with them, it all just falls into place.

And I've known several people who didn't know the color code and simply use their trusty VOM to measure the values. Trouble is, the error in their ±3% meter that was pushing the extremes of its specs caused them to misread the values of all those 1% metal film resistors.