For right now here's the tl:dr: Take your post payout listed on steemit.com and multiply by 5.5. That will tell you how many USD worth of Steem and SBD you're going to get for your post at the time of payout. If you multiply by 5 this will give you a rough estimate of what it's worth in liquid rewards.
When you look at a post and see the value that's not actually USD (even though there is a dollar sign there). That number references post rewards, which is a combination of SBDs and SP that are going to be rewarded by the blockchain. It's pretty complicated how it works so I thought I'd break it down for you so that'd you know what a post is worth.
I'm going to take my last post to payout as an example: https://steemit.com/mspwaves/@aggroed/minnow-mayor-town-hall-live-in-90-min
The post payout was 142.01. I'm going to call the units here Pay (post payout)
As the author I received 113.79Pay.
As curators folks received 28.22Pay
From those author rewards due to conversions in the system those 113.79 Pay turn into 56.895 SBD and 33.448 Steem Power.
(you'll notice that SBD is at exactly 50% of Pay is dolled out as SBD rewards, "Rewards" when you post initially says 50/50 but conversions set by the witnesses distort it from that)
SBDs are worth $12.8 USD at the time of writing this. SP is worth 1.8.
So, from SBD I earned $728 USD. From SP I earned $60USD. For a grand total of $788.46.
So, if you're looking for a fast way to figure out what it's worth to you in USD simply take the post reward shown on the post and multiply by 5.5 and that will tell you roughly how much it's worth in USD (this number is undergoing a lot of change right now because SBDs and Steem values are bouncing a lot). If you want to know what the liquid portion is worth just multiply post reards by 5.
https://docs.google.com/spreadsheets/d/18FOyy7ngm5Ar-7TWyaW0b46SYYFX4gqZgQhLZ7YlagY/edit?usp=sharing
This thing is subject to change so don't take this as certain forever. Edit. It would also seem that people like to edit google sheets to the point they are unusable...
