Rate is supposed to be seen as more of a guideline than anything else. That being said, here are the breakdowns across currencies.
$: 0-50/hr or 0-500/day
$$: 50-100/hr or 500-1,000/day
$$$: 100-150/hr or 1,000-1,500/day
$$$$: 150+/hr or 1500+/day
£: 0-20/hr or 0-200/day
££: 20-40/hr or 200-400/day
£££: 40-60/hr or 400-600/day
££££: 60+/hr or 600+/day
€: 0-30/hr or 0-300/day
€€: 30-60/hr or 300-600/day
€€€: 60-90/hr or 600-900/day
€€€€: 90+/hr or 900+/day