How many K is 30 °C?
30 °C = 303.15 K
It is 303.15 K, so saying 303 K is fine — rounding is within 0.5%.
And how many °C is 30 K?
30 K = -243.15 °C
Formula: K = °C × 1 + 273.15
°C to K around this value
12 °C285.15K
14 °C287.15K
16 °C289.15K
18 °C291.15K
20 °C293.15K
22 °C295.15K
24 °C297.15K
26 °C299.15K
28 °C301.15K
30 °C303.15K
32 °C305.15K
34 °C307.15K
36 °C309.15K
38 °C311.15K
40 °C313.15K
42 °C315.15K
44 °C317.15K
46 °C319.15K
48 °C321.15K
50 °C323.15K