Stupnice Wattmetru				

hodnota	dílků		swr	dílků
80	80		set	80
70	75		10	65
60	69		5	54
50	63		3,0	40
40	57		2,0	26
30	49		1,75	22
20	40		1,5	17
15	35		1,4	15
10	28		1,3	12
5	20		1,2	8
0	0		1,1	4
			1	0


Since SWR, Standing Wave Ratio is a ratio, there is no unit of measure. 
Reflected power in watts can be calculated if input power and SWR are known.

Maybe the easiest answer is to state a few points of SWR with reflected power percentages and wattages approximated:
SWR %power reflected TX Power Reflected Power
1:1 0% 50W 0W
1.5:1 4% 50W 2W
2:1 10% 50W 5W
3:1 25% 50W 12.5W
4:1 36% 50W 18W
5:1 44.4% 50W 22.2W

THE FORMULA
If you want to compute power reflected knowing SWR and power transmitted, the formula is:

Reflected Power = ( ( (SWR - 1) / (SWR + 1) ) ^ 2) * TX Power

Example:
SWR = 2:1, TX Power = 10 Watts

SWR - 1 = 2-1 = 1
------- = --- ---
SWR + 1 = 2+1 = 3

1
--- squared = 0.11111111 or 11.1% reflected power
3

10 watts input multiplied by 0.1111111 = 1.1 Watts reflected 

Hope this helps,
Michael, KF4PQQ