Warhammer 40K 11th Edition Army Composition Rules Explained

Every legal Warhammer 40,000 army list in 11th Edition has to satisfy the same handful of structural rules before a single dice roll happens: it has to fit a battle size, stay inside a Detachment Points budget, respect a cap on how many times you can repeat a unit, and take no more Enhancements than the size allows. None of these are complicated on their own. Together they are the reason lists get bounced at the tournament check-in desk.

This guide walks through each rule, what changes between the three battle sizes, and the specific places lists most often break.

The three battle sizes

11th Edition keeps the three familiar tiers, and almost every composition rule keys off which one you picked.

Strike Force at 2,000 points is the competitive standard and the size every tournament pack you will meet is built around. Incursion is the one worth knowing properly if you play at a club with limited evenings — it is not simply "Strike Force but smaller", because both the DP budget and the duplicate limit tighten.

A note on Onslaught: the Detachment Points budget for 3,000-point games is the one number in this table that is not yet settled in the published rules. If you are building at Onslaught, check the current pack for your event rather than assuming it scales linearly from Strike Force.

Detachment Points: the budget that replaced "pick one detachment"

The single biggest structural change from 10th Edition is that you are no longer limited to one detachment. Instead, every detachment has a Detachment Points cost, and your army has a DP budget determined by battle size. You can take any combination of detachments whose DP costs fit inside the budget.

At Strike Force you have 3 DP. In practice that means one 3 DP detachment, or a 2 DP plus a 1 DP, or three 1 DP detachments — whatever combination adds up.

There is one exception worth committing to memory, because it catches people out constantly:

At Incursion, the budget is 2 DP — but you may instead take a single 3 DP detachment on its own. The moment you add a second detachment, the normal 2 DP budget snaps back into force.

So at Incursion, a lone 3 DP detachment is legal; a 3 DP detachment plus a 1 DP detachment is not, even though the "wrong" version only costs 1 DP more than the legal 2+1 split. If you want two detachments at Incursion, both have to fit inside 2 DP total.

We wrote a fuller breakdown of how the DP system changes list building in Detachment Points explained.

Enhancements

Enhancements are the upgrades your detachment offers to Characters. The rules that bite:

If you build in GrimSlate's list builder, Enhancements are filtered to the Characters that can legally take them and the counter shows how many of your allowance you have spent.

The duplicate limit

You may not include the same datasheet more times than your battle size allows: twice at Incursion, three times at Strike Force and Onslaught.

Three exceptions matter:

The Battleline multiplier is the one that changes lists. If a datasheet is Battleline for your detachment, six copies is a completely different plan from three — and some detachments *grant* the Battleline keyword to a unit that does not normally have it. That grant is real, it applies at list-building time, and it means the same datasheet has a different duplicate limit depending on which detachment you brought.

Warlord

Exactly one Character in your army is your Warlord. Two constraints people miss:

Dedicated Transports

A Dedicated Transport is bought for a specific unit and does not count towards your duplicate limit. The ceiling is six per army at every battle size.

Transport capacity is checked at list-building time in most tournament packs: if you have assigned twelve models to a ten-capacity vehicle, the list is illegal before you deploy. Keywords matter here too — many transports refuse Terminator-sized models entirely, or count them as more than one model each.

The order to build in

Most illegal lists come from building in the wrong order and discovering a constraint after the points are already spent. A sequence that avoids most of it:

Checking a list without doing it by hand

Every rule above is mechanical, which means it can be checked automatically. GrimSlate validates all of them live as you build — DP budget including the Incursion single-detachment exception, Enhancement caps and keyword restrictions, duplicate limits with Battleline multipliers and Epic Hero uniqueness, and transport capacity including attached leaders.

You can start a list for free, and the app works offline once loaded, which is genuinely useful when the venue's wifi gives out. If you are coming from a 10th Edition list, our conversion guide covers what carries over and what has to be rebuilt.

Quick reference