from Den Haag to Rotterdam by bike?

thank you so much!
what a great source for route planning. it takes around 1 hour and 47 minutes to commute from one place to another by bike and approximately 1 hour and 23 minutes by public transport. i'm definitely up for cycling there. again, thank you for your advice.

Here is a site dedicated to bike travel and navigation in the Netherlands:
http://www.fietsersbond.nl/op-fiets/fietsroute-planner (in Dutch)

The 'green' planner is for recreational routes using the 'hub' (knooppunten) system. The idea is you write down the hub numbers the planner suggests. These numbers are signposted throughout the country.

The 'red' planner is a door to door planner to get the fastest route between points with a very detailed map and instructions.

They are planning a number of fast cycle-connections between towns in the Netherlands.
http://www.fietssnelwegen.nl
Rotterdam and Den Haag are in the pipeline.
If I remember well from the 'news', Utrecht-Amsterdam is ready to use.

Some 5 have been realized

Apart from the reputated viamichelin, this site might be helpful:
http://www.fietsersbond.nl/op-fiets/fietsroute-planner

For locally orientated experts (I'm not): it makes sense to tell (exactly) the points to provide a point-to-point itinerary; complicated and much to win parts are in the towns!

Yorick, you were faster than I was...
So some overlap.
Looking in my 'knooppunten'-book, there's a rather straight road Den Haag-Rotterdam.

Delftweg-Schieweg-Delftweg, ending just west of airport Rotterdam.

But again: it depends strongly on point-to-point.

Note that whilst that part of Holland is as flat as a pancake, it can get windy, brutally so, you can feel like you're slogging up one of the Alpine passes.

I was born and raised in the Netherlands and have lived there for 40 years now. I do not have a driver licence and I do not need one. I do all the travelling either by bicycle (short distances up to 15 km) or by train. Anyway, I make a lot of kilometers (sorry.. miles) on one of my bicycles. Doing Rotterdam - The Hague on a bike on a daily base is pretty tough. There is an excellent bicycle path just behind the dunes all the way from Hoek van Holland to The Hague but there is always a lot of wind. It will take you at least 2 hours to make it -- 1.5 if you are a well-trained racing cyclist. I would say half the distance (e.g., from Delft to The Hague) is pretty doable. Delft is a great place to live anyway -- just in-between Rotterdam and the Hague. Kinda Amsterdam scale 1:2

Robert I think the scale is more 1:5 a bit like a babyshark to a shark.
But babyshark will be in her/his puberty now and doesn't answer.

http://home.planet.nl/~pagklein/gemprov.html If you're interested...
But indeed, gorgeous town!