SCP: Secret Laboratory is a free multiplayer horror game set inside a Foundation site during a full containment breach. Each round assigns your role at random: Class-D trying to escape, a Scientist waiting on rescue, a Facility Guard, or one of the anomalies hunting everybody else. Death is permanent for that round, and the facility runs on hard timers that will kill you whether or not anything else does.
This guide covers everything you need: core mechanics, the best builds, equipment worth investing in, location progression, and the tips that actually make a difference.
Core Mechanics
Role assignment and respawn waves
You spawn as Class-D, a Scientist, a Facility Guard or an SCP with no say in the matter. Dead humans return in respawn waves as Nine-Tailed Fox or Chaos Insurgency, which is why a round rarely ends when the first team is wiped out.
Keycard access levels
Doors and lockers are gated by keycard permissions, running from low tier Janitor and Scientist cards up to O5. Class-D spawn with nothing, so their opening two minutes are entirely about getting a card off somebody else.
SCP-914 refinement
The clockwork machine in Light Containment has five settings: Rough, Coarse, 1:1, Fine and Very Fine. Fine upgrades items, Very Fine upgrades faster but can destroy them outright, and 1:1 never destroys anything while recharging radios and the Micro H.I.D.
Light Containment decontamination
At 11 minutes 45 seconds into the round, Light Containment starts decontaminating and then kills everything still inside, SCPs included. The announcement is your cue to leave whether or not you got what you came for.
Emergency Power Stations and the Alpha Warhead
Three Emergency Power Stations sit in Heavy Containment, and activating all three re-contains SCP-079. The Alpha Warhead is the other ending: once armed it runs a 90 second countdown on default settings and kills everyone left in the Light, Heavy and Entrance zones.
For a deeper dive into how these systems interact, see our SCP: Secret Laboratory combat guide.
Builds Overview
| Build | Tier | Playstyle | Key Stats |
|---|---|---|---|
| Class-D Personnel | A | Versatile approach | Balanced stats |
| Scientist | A | Versatile approach | Balanced stats |
| Facility Guard | A | Versatile approach | Balanced stats |
| Nine-Tailed Fox | A | Versatile approach | Balanced stats |
| Chaos Insurgency | A | Versatile approach | Balanced stats |
For full build breakdowns with gear and stat priorities, see our SCP: Secret Laboratory builds guide. For rankings, check the tier list.
Equipment Guide
| Equipment | Why It Matters | Best For |
|---|---|---|
| COM-15 | A slow firing 9x19mm sidearm from PG Arms with high damage per shot. | Class-D and Scientists who need something rather than nothing. |
| FSP-9 | The standard issue submachine gun of Facility Guards: light damage per hit, high rate of fire, and a magazine that empties quickly if you panic. | Guards holding short corridors in Light and Heavy Containment. |
| Crossvec | A compact automatic weapon sitting between the FSP-9 and the rifles, controllable enough to land headshots in a corridor fight without a rifle's weight. | Anyone who picks one up in Heavy Containment and wants accuracy at short range. |
| MTF-E11-SR | The Nine-Tailed Fox rifle and the strongest general purpose firearm in the game, which is why an organised respawn wave usually flips the direction of a round. | Trading with SCPs at range while three teammates fire at the same target. |
| Logicer | The Chaos Insurgency light machine gun, carrying enough ammunition to keep firing through the window where everyone else has to reload. | Chaos Insurgency pushing Entrance Zone or holding the Surface for escaping Class-D. |
COM-15: A slow firing 9x19mm sidearm from PG Arms with high damage per shot. It is a backup rather than a primary, and it is common enough that Class-D often find one first.
FSP-9: The standard issue submachine gun of Facility Guards: light damage per hit, high rate of fire, and a magazine that empties quickly if you panic.
Crossvec: A compact automatic weapon sitting between the FSP-9 and the rifles, controllable enough to land headshots in a corridor fight without a rifle's weight.
MTF-E11-SR: The Nine-Tailed Fox rifle and the strongest general purpose firearm in the game, which is why an organised respawn wave usually flips the direction of a round.
Logicer: The Chaos Insurgency light machine gun, carrying enough ammunition to keep firing through the window where everyone else has to reload.
Full breakdowns in our SCP: Secret Laboratory weapons guide.
Location Progression
| Location | Level Range | Key Rewards |
|---|---|---|
| Light Containment Zone | First 11 minutes 45 seconds of the round | SCP-914 refinement, low tier keycards, starting medkits |
| Heavy Containment Zone | Mid round, after decontamination begins | Generator activation, higher tier keycards, Micro H.I.D. |
| Entrance Zone | Mid to late round | Escape route, weapon lockers, checkpoint control |
| Surface Zone | Late round | Escape, role conversion, Alpha Warhead controls |
| Pocket Dimension | Any time SCP-106 is loose | Survival, a return trip into the facility |
Light Containment Zone: Class-D cells, SCP-914, SCP-173's chamber and the airlocks. Busiest area of the round for eleven minutes, and lethal ground after that.
Heavy Containment Zone: Three Emergency Power Stations, SCP-079's server room, SCP-106's chamber and the route toward the warhead. Most SCP fights happen down here.
Entrance Zone: Offices, checkpoints and the road to the Surface. Nine-Tailed Fox arrive through here, which makes it the main human against human battleground.
Surface Zone: The escape point for Class-D and Scientists alike, and where both respawn teams arrive. Escaping as Class-D turns you into Chaos Insurgency, and escaping as a Scientist turns you into Nine-Tailed Fox.
Pocket Dimension: Where SCP-106 drags its victims. There are real exits and there are lethal ones, so the answer is to keep moving and read the tunnels rather than freeze in place.
See our maps & locations guide for detailed area breakdowns and our walkthrough for the optimal progression path.
Tips That Actually Matter
- Decontamination begins at 11 minutes 45 seconds, earlier than the fifteen minute figure players quote. Start your own clock at round start and be out of Light Containment with a full minute in hand.
- SCP-173 is frozen while any living player has it in view, so a group should have one person walking backwards watching it while everyone else moves. The moment all of them turn to run at once, the group dies.
- On SCP-914, 1:1 never destroys an item and recharges radios and the Micro H.I.D. Fine upgrades with a chance at a better keycard, and Very Fine upgrades faster but can delete the item entirely.
- Class-D spawn with nothing while Scientists spawn with a Level 2 keycard and a medkit, which is exactly why Class-D groups hunt Scientists first. As a Scientist, avoid the cell block and head for Entrance Zone.
- The three Emergency Power Stations in Heavy Containment re-contain SCP-079 once all of them are running. Each takes time and makes noise, so start one only with somebody watching the corridor behind you.
- The Alpha Warhead runs a 90 second countdown on default settings and kills everything in the Light, Heavy and Entrance zones. If you are Class-D when it arms, you run for the Surface and abandon the loot.
- Escaping as Class-D turns you into Chaos Insurgency and escaping as a Scientist turns you into Nine-Tailed Fox, so the Surface is a checkpoint rather than an exit. Plan for a second life with a rifle in it.
- Nine-Tailed Fox lose most rounds where the squad splits to clear faster. The MTF-E11-SR trades well with SCPs, but only when three or four of them are hitting the same target inside the same few seconds.
- SCP-106 pulls victims into the Pocket Dimension where several exits kill instantly. Keep moving and check tunnels rather than standing still, because the dimension has its own timer working against you.
- A Janitor keycard is not worthless. Feed it into SCP-914 on Fine and you have a genuine chance at something that opens doors in Heavy Containment, which beats carrying it as a souvenir.
Common Mistakes to Avoid
- Staying in Light Containment past the decontamination announcement to finish one more SCP-914 run.
- Splitting the Nine-Tailed Fox squad to clear rooms faster, then losing four players one at a time.
- Sprinting past SCP-173 with your back turned instead of walking backwards while watching it.
- Arming the Alpha Warhead while half your own team is still down in Heavy Containment.
- Looking directly at SCP-096's face and then trying to hide, when it will hunt you across the whole facility.
Frequently Asked Questions
Is SCP: Secret Laboratory free?
Yes, it is free on Steam with no paid progression. Roles are assigned randomly every round, so nothing about what you can play changes with hours logged.
How do I escape as Class-D?
Get a keycard, move through Entrance Zone to the Surface, and reach the escape area. Escaping turns you into Chaos Insurgency, so you return armed instead of simply leaving the round.
What triggers decontamination?
A round timer, not any player action. Light Containment begins decontaminating at 11 minutes 45 seconds and then kills everyone left inside, SCPs included, which makes it a hard deadline for SCP-914 runs.
How do you deal with SCP-173?
Keep it in view so it cannot move, and never travel alone. Killing it takes a coordinated Nine-Tailed Fox squad with MTF-E11-SR rifles, and the Alpha Warhead handles it if nobody can get a firing line.
Which SCP is hardest to play well?
SCP-049 and SCP-079. SCP-049 has to land a slow attack to turn corpses into SCP-049-2, and SCP-079 plays through cameras and doors rather than a body, so both punish bad timing far more than bad aim.
More SCP: Secret Laboratory Guides
- SCP: Secret Laboratory Best Builds
- SCP: Secret Laboratory Tier List
- SCP: Secret Laboratory Walkthrough
- SCP: Secret Laboratory Beginner's Guide
- SCP: Secret Laboratory Tips & Tricks
- SCP: Secret Laboratory Weapons Guide
- SCP: Secret Laboratory Combat Guide
- SCP: Secret Laboratory Boss Guide
- SCP: Secret Laboratory Maps & Locations
- SCP: Secret Laboratory Crafting Guide
- SCP: Secret Laboratory Classes & Characters
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- Lethal Company Guide: horror game with similar mechanics
- Dead by Daylight Guide: horror game with similar mechanics
