Quickened spell and movement/dodge, does order matter?

As you can use an action to, dash, dodge, attack, cast spell, etc.

Am I allowed to walk my normal movement >> use my action to dash >> then use 2 SP to quicken a spell/cantrip?

My DM reasons like this:
Because I chose to Dash with my action, I do not have any action available to convert into a bonus action and I cannot do what I described above. The official ruling says: "When you cast a spell that has a casting time of 1 action, you can spend 2 sorcery points to change the casting time to 1 bonus action"

I would plead that making that spell a bonus action would not require me to have an action available. And is counted as a free action.

• Free action? Are you referring to interacting with an object? – KorvinStarmast May 23 '18 at 19:11
• Because of the ambiguity of "When you cast a spell", i've tweeted Jeremy Crawford about this specific wording. – Premier Bromanov May 23 '18 at 20:41

Metamagic has no action cost, order is entirely up to you

There is no action cost listed (only the resource cost) for utilizing any Metamagic abilities, so your action remains completely available.

In your specific case, the options are as follows:

• Spend Metamagic resource to convert Spell to a Bonus action

• Use Bonus Action

Timing of Movement and Actions are also up to you:

In addition Bonus Action timing is stated as:

You choose when to take a bonus action during your turn, unless the bonus action's timing is specified, and anything that deprives you of your ability to take actions also prevents you from taking a bonus action.

Breaking up Movement for Actions and Bonus Actions

You can break up your movement however you like on your turn. For more details, see this related question on how characters can move and act during their turn and the answers there.

• I think it's worth noting that you can (assuming 30 feet move speed) move 15 feet, quicken cast a spell, move 10 feet, then use your action to dash, then move the remaining 35 feet. There seems to be confusion on several levels between the player and DM on how the action economy works, and they seem to be treating "move 30 feet" as an atomic action like in 3.5e or 4e. – Ethan May 23 '18 at 18:12
• @Ethan You are most likely correct there, does the link do enough at the end? I didn't want to add too much to this answer when it's available on another question. – NautArch May 23 '18 at 18:19
• That mostly covers it. I think the question is certainly answered, but the group seems to have the wrong idea of what the dash action does. Its actual effect is to add your base movespeed to your movement this turn, not to take an extra move. Not relevant to the question as asked, and I honestly think there should be some boilerplate explaining this since it comes up a lot. – Ethan May 23 '18 at 18:23
• Great answer. You also might want to address As my DM reasons like this: That if I chose to Dash with my action I do not have any action available to convert into a bonus action I cannot do what I described above. The important thing is that Metamagic doesn't convert an action to a bonus action, it converts a spell's casting time from action to bonus action. – lucasvw May 23 '18 at 20:09
• @lucasvw That is literally my Headline. But I did notice my second sentence is crazy incomplete. Fixing now. – NautArch May 23 '18 at 20:14

Order does not matter Not in this case anyway.

Your movement, action and bonus action can generally be taken in any order unless some specific action/bonus action indicates otherwise.

There is nothing in the description of Quicken that says that spending the points uses up an action itself (if it did the Quicken feature would be pointless!) or that it must be done before or after your normal action. It only says "when you cast a spell".

Essentially - you are casting the spell faster than normal. The way this is represented in the rules is by converting something that would normally take an action into a bonus action instead.