What does it cost to level Engineering right now?

10.3kg in reagents at today's US auction prices, over about 135 crafts. Sell the results and it comes back to 10.1kg.

Where do these numbers come from?

The skill thresholds are read from the game client data for build 12.1.0.68914. The prices are the region-wide auction house, refreshed every few minutes; these are the snapshot taken at 16:57 UTC.

Why does the route change when I reload?

Because the prices did. The cheapest recipe for a stretch of skill is whichever one's reagents are cheapest at that moment, and that moves through the day.

Profession leveling · Northrend Engineering · US · prices as of 16:57 UTC

Engineering leveling 1 → 75 · Northrend Engineering

10.3kg in reagents over about 135 crafts. Sell what you make and it comes back to 10.1kg.

Start skill

Trainer recipes only

Recipe names carry the colour the profession window gives them: orange is a point every craft, yellow is three in four, green is one in four.

Before the first craft — buy it all at once

One trip to the auction house. Vendor lines are cheaper from the profession vendor than from the board.

ReagentNeedEachTotal

Saronite Bar×45219

9,026

×4529,026

Volatile Blasting Trigger×3218

Total10,313

Step 1 · Skill 1 → 15

Orange

EMP Generator

trainer

About 14 crafts.55

per skill point3

Tinker's Kit×14

Step 2 · Skill 15 → 25

Orange

Nitro Boosts

trainer

About 10 crafts.39

per skill point3

Tinker's Kit×10

Step 3 · Skill 25 → 45

Orange→Green

Mind Amplification Dish

trainer

About 37 crafts.146

per skill point7

Tinker's Kit×37

Step 4 · Skill 45 → 60

Orange→Green

Global Thermal Sapper Charge

trainer

About 32 crafts.1,222

per skill point81

Saronite Bar×32

Volatile Blasting Trigger×32

Step 5 · Skill 60 → 75

Yellow→Green

Heartseeker Scope

trainer

About 42 crafts.8,849

per skill point589

Saronite Bar×420

Twilight Opal×84

Skill 75 — done. Now sell what you made.

Crafted itemUnitsEachTotal

Heartseeker Scope422

105

42105

Global Thermal Sapper Charge16050

16080

Capped at what the market takes in 3 days, so a route never pretends to sell hundreds at once.

Back in your pocket10,128

What's worth crafting with Engineering right now

Questions

How this route is built

What does it cost to level Engineering right now?: 10.3kg in reagents at today's US auction prices, over about 135 crafts. Sell the results and it comes back to 10.1kg.
Where do these numbers come from?: The skill thresholds are read from the game client data for build 12.1.0.68914. The prices are the region-wide auction house, refreshed every few minutes; these are the snapshot taken at 16:57 UTC.
Why does the route change when I reload?: Because the prices did. The cheapest recipe for a stretch of skill is whichever one's reagents are cheapest at that moment, and that moves through the day.

A first craft pays Knowledge, not skill, so it is shown as a badge and left out of the craft count. Vendor reagents are priced at the lower of the vendor and the auction house.