How many km is 3 light years?

3 light years = 28,382,191,417,742 km

It is 28,382,191,417,742 km, so saying 28,382,191,417,742 km is fine — rounding is within 0.5%.

And how many light years is 3 km?

3 km = 0 light years

Formula: km = light years × 9,460,730,472,580.8

1.2 light years11,352,876,567,097km

1.4 light years13,245,022,661,613km

1.6 light years15,137,168,756,129km

1.8 light years17,029,314,850,645km

2 light years18,921,460,945,162km

2.2 light years20,813,607,039,678km

2.4 light years22,705,753,134,194km

2.6 light years24,597,899,228,710km

2.8 light years26,490,045,323,226km

3 light years28,382,191,417,742km

3.2 light years30,274,337,512,259km

3.4 light years32,166,483,606,775km

3.6 light years34,058,629,701,291km

3.8 light years35,950,775,795,807km

4 light years37,842,921,890,323km

4.2 light years39,735,067,984,839km

4.4 light years41,627,214,079,356km

4.6 light years43,519,360,173,872km

4.8 light years45,411,506,268,388km

5 light years47,303,652,362,904km