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OSRS Barrows Loot Calculator: EV & GPH Optimization

This calculator helps you determine the expected value (EV) and gold per hour (GPH) for Barrows runs in Old School RuneScape. Whether you're a casual player looking to make consistent profit or a hardcore farmer optimizing every second of your runs, understanding these metrics is crucial for maximizing your efficiency at one of OSRS's most iconic PvM activities.

The Barrows minigame has been a cornerstone of OSRS moneymaking since its release in 2005, offering players a unique blend of combat challenges and rewarding loot mechanics. Our calculator uses the official OSRS Barrows chest reward algorithm to compute precise drop rates, expected values, and hourly profit projections. By inputting your run time, Morytania Diary status, and current Grand Exchange prices, you can model different scenarios and compare Barrows profitability against other popular moneymaking methods like Vorkath, Zulrah, or Chambers of Xeric.

Understanding expected value is fundamental to efficient Barrows farming. EV represents the average loot value you'll receive per chest across thousands of runs, accounting for both rare Barrows equipment drops (1/450 per item at max Reward Potential) and common rewards like runes, coins, and bolt racks. While you might experience dry streaks where you receive no unique items for 50+ chests, or hot streaks with multiple items in 10 chests, EV provides the long-term average that lets you make informed decisions about time investment.

The Morytania Hard Diary is perhaps the single most important factor in Barrows profitability, providing a 50% increase to all rune rewards from chests. This bonus alone adds approximately 9-10k gold per chest, translating to 400-500k additional profit per hour for players completing 40+ chests hourly. Our calculator lets you toggle this bonus on and off, clearly demonstrating why completing the diary should be your first priority before committing to serious Barrows grinding. The diary requirements—including 70 Prayer, completion of Haunted Mine, and various skill checks—are well worth the investment, typically paying for themselves within 50-100 chest openings.

Gold per hour (GPH) is where efficiency optimization truly shines. While per-chest EV remains constant regardless of your speed, GPH scales directly with how many chests you can open per hour. A player completing runs in 90 seconds (40 chests/hour) will earn significantly more than someone taking 150 seconds per run (24 chests/hour), even with identical loot tables. This calculator allows you to model different run times, helping you identify bottlenecks in your routing, gear setup, or prayer management. Elite players achieve sub-75 second runs through optimized pathing, prayer flicking, and efficient Reward Potential management, pushing GPH above 2.5M gold per hour.

Use this calculator to experiment with different price scenarios, compare pre- and post-diary profitability, and determine whether Barrows fits your current account progression. The results update instantly as you adjust parameters, making it easy to model market fluctuations, test different efficiency strategies, or share your setup with friends via shareable links. Whether you're planning your first Barrows trip or your ten-thousandth, data-driven decisions will always outperform guesswork in the long run.

OSRS Barrows Loot Calculator

Calculate EV, gold per hour, and unique probabilities. Prefilled example applied.

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Item Value Overrides
Tip: search the item and override only what you need
0 overrides
ItemBase (gp)Override (gp)
Ahrim's robetop1,800,000
Ahrim's robeskirt1,650,000
Ahrim's hood950,000
Ahrim's staff850,000
Dharok's greataxe900,000
Dharok's helm750,000
Dharok's platebody950,000
Dharok's platelegs850,000
Guthan's warspear800,000
Guthan's helm700,000
Guthan's platebody900,000
Guthan's chainskirt750,000
Karil's crossbow650,000
Karil's coif550,000
Karil's leathertop700,000
Karil's leatherskirt650,000
Torag's hammers500,000
Torag's helm450,000
Torag's platebody600,000
Torag's platelegs550,000
Verac's flail700,000
Verac's helm600,000
Verac's brassard750,000
Verac's plateskirt650,000
Bolt racks15,000
Coins3,000
Runes (average)8,000
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EV
196,285
GPH
7,851,411

OSRS Barrows Loot Calculation: Methodology & Practical Guide

This calculator uses the official OSRS Barrows chest reward mechanics to compute drop rates, expected value (EV), and gold-per-hour (GPH). Understanding the two-stage loot system and probability models will help you optimize your Barrows runs for maximum profit. Below, we explain the assumptions, formulas, real examples, edge cases, and mistakes to avoid.

Assumptions

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Barrows uses a two-stage loot system: First, the game rolls for rare items (Barrows equipment) with probabilities determined by your Reward Potential. Second, it rolls for common rewards (runes, bolt racks, coins). The rare table is mutually exclusive—getting one Barrows item precludes getting another in the same chest.
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Reward Potential is capped at 1,012 (88%): Killing all 6 brothers grants 874 potential. Killing 2 skeletons + 1 bloodworm in tunnels adds 138, reaching the optimal 1,012. Going beyond this (e.g., killing all monsters) dilutes the loot table with bolt racks and key halves. See the Reward Potential guide for details.
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Morytania Diary provides a multiplicative bonus: Completing the Morytania Hard Diary grants a 50% increase in runes received. This does not affect unique drop rates but significantly boosts EV from common rewards. Our calculator allows toggling this bonus on/off.
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Market prices fluctuate: Item values are based on real-time Grand Exchange (GE) prices or user-provided overrides. EV calculations are snapshots—actual profit depends on when you sell items. Volatile items like Ahrim's staff can swing EV by 100k+ per chest.
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Run time affects GPH but not per-chest EV: A 90-second run and a 120-second run have identical expected loot per chest. However, faster runs yield more chests per hour, multiplying your hourly profit. Efficiency matters for GPH optimization.

Formula & Pseudocode

Unique Item Drop Rate:

P(unique) = (RewardPotential / 1,012) × (1/450) per brother

Each brother has a 1/450 base chance to drop their specific item if you achieve max Reward Potential (1,012). At 1,012 potential, your odds are 1/450 per brother set. Lower potential reduces this probability proportionally. This is a per-item roll, not a "any unique" roll.

Any Unique Probability (Union):

P(any unique) = 1 - (1 - p)^n

To find the probability of getting at least one unique item across multiple independent drops (e.g., n=24 items with p=1/450 each), use the union probability formula. This accounts for the fact that drops are mutually exclusive within a single chest but independent across chests. Learn more in our union probability glossary.

Expected Value (EV) per Chest:

EV = Σ(value_i × P(item_i)) for all items

Sum the product of each item's value and its drop probability. For example, if Guthan's helm is worth 500k with a 1/450 chance, it contributes 500,000 × (1/450) = 1,111 gp to EV. Add contributions from all 24 Barrows items plus common rewards (runes, coins, etc.). See our EV glossary entry.

Gold Per Hour (GPH):

GPH = EV_per_chest × (3600 / seconds_per_run)

Multiply per-chest EV by chests per hour. If your run takes 90 seconds, you complete 40 chests/hour (3600 ÷ 90). If EV is 75k per chest, GPH = 75,000 × 40 = 3,000,000 gp/hour. This metric helps compare Barrows to other moneymaking methods like Vorkath or Zulrah.

Barrows Chest Reward Algorithm

function rollBarrowsChest(rewardPotential, diaryBonus):
  // Stage 1: Roll for Barrows items
  for each of 24 Barrows items:
    dropChance = (rewardPotential / 1012) × (1 / 450)
    if random(0, 1) < dropChance:
      award item and STOP (mutually exclusive)
  // Stage 2: Roll for common rewards
  runeAmount = rollRuneTable(rewardPotential)
  if diaryBonus == true:
    runeAmount *= 1.5
  coinsAmount = random(100, 3000)
  boltRacks = rollBoltRackTable(rewardPotential)
  return [barrowsItem or null, runes, coins, boltRacks]

Real Scenario: 100 Barrows Chests with Morytania Hard Diary

Scenario:

You plan to complete 100 Barrows chests with max Reward Potential (1,012) and Morytania Hard Diary active. Your average run time is 90 seconds. Current GE prices show Guthan's warspear at 1.2M, Karil's coif at 40k, and average rune rewards worth 18k per chest (before diary). What are your expected outcomes?

Step 1: Calculate Probability of At Least One Unique in 100 Chests

P(any unique) = 1 - (1 - 24×(1/450))^100 ≈ 1 - (0.9467)^100 ≈ 99.3%
With 24 Barrows items each at 1/450, the combined probability per chest is 24/450 ≈ 5.33%. Over 100 chests, you have a 99.3% chance to receive at least one unique item. Note this doesn't mean exactly 1—you might get 10 or more due to variance.

Step 2: Compute Expected Number of Unique Items

E[uniques] = 100 × (24 / 450) ≈ 5.33 unique items
On average, you'll receive 5-6 Barrows items across 100 chests. This is the expected value, but actual results vary. You might get 0 (bad luck) or 15 (good luck). The distribution follows a binomial model. Check our variance guide for dry streak probabilities.

Step 3: Calculate EV from Common Rewards with Diary

Base runes = 18k × 1.5 = 27k. Coins ≈ 1.5k. Total common EV ≈ 28.5k per chest.
The Morytania Hard Diary boosts rune rewards by 50%, increasing average rune loot from 18k to 27k. Adding coins and minor items gives ~28.5k per chest from common rewards alone. Over 100 chests, that's 2.85M gp guaranteed (ignoring variance).

Step 4: Add EV from Unique Items

Average unique value ≈ 350k. EV per chest = 350k × (24/450) ≈ 18.7k.
If the average Barrows item is worth 350k (weighted by drop rates), each chest contributes ~18.7k from potential uniques. Total per-chest EV = 28.5k (common) + 18.7k (uniques) = 47.2k. Over 100 chests, expect ~4.72M gp. Actual profit depends on which items you get—Guthan's spear (1.2M) vs. Karil's coif (40k).

Step 5: Calculate GPH (Gold Per Hour)

90s per run = 40 chests/hour. GPH = 47.2k × 40 = 1,888k gp/hour.
At 90 seconds per chest, you complete 40 chests per hour. Multiplying per-chest EV (47.2k) by 40 gives 1.888M gp/hour. This is competitive with mid-tier PVM like Vorkath. If you reduce run time to 75 seconds (48 chests/hour), GPH jumps to 2.27M/hour—efficiency pays.

Result:

Expected Outcome: In 100 chests (2.5 hours at 90s/run), you'll likely receive 5-6 Barrows items (99.3% chance of at least one) and ~2.85M from common rewards. Total expected profit: ~4.72M gp. Actual results will vary due to RNG, but the diary bonus is essential—it adds ~950k gp over 100 chests. Always complete Morytania Hard before serious Barrows grinding.

Edge Cases

Exceeding 1,012 Reward Potential (Over-killing Monsters)

Problem: If you kill too many monsters in the tunnels (e.g., all skeletons and bloodworms), your Reward Potential exceeds 1,012. This dilutes the loot table by adding more bolt racks and loop/tooth halves, which are low-value. Solution: Kill exactly 6 brothers + 2 skeletons + 1 bloodworm (or equivalent 138 potential from other monsters). Use a Reward Potential tracker plugin to monitor in real-time.

Forgetting to Toggle Diary Bonus in Calculator

Problem: If you have Morytania Hard Diary but forget to enable it in the calculator, your EV will be underestimated by ~9-10k per chest (the rune bonus). Solution: Always verify the diary toggle matches your in-game status. The calculator defaults to OFF—manually enable it if you have the diary. This affects GPH by ~400k/hour at 40 chests/hour.

Item Prices Crashing Mid-Grind

Problem: Barrows item prices are volatile. For example, Ahrim's robetop might drop from 800k to 500k during a weekend due to bot farms or game updates. If you're holding items, your realized profit will differ from calculated EV. Solution: Sell high-value uniques immediately or use the calculator's price override feature to model worst-case scenarios. Track price trends on OSRS GE Tracker.

Comparing Barrows to Other Moneymakers Without Accounting for Variance

Problem: Barrows has high variance—you might go 50 chests dry or get 3 items in 10 chests. Comparing raw GPH to consistent methods like Vorkath (which has lower variance) can be misleading. Solution: Consider your risk tolerance. If you need consistent hourly income, Barrows might not be ideal for short sessions. For long-term grinding (500+ chests), variance evens out and EV becomes reliable. See our variance analysis blog.

Common Mistakes to Avoid

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Not completing Morytania Hard Diary before grinding Barrows

Why it's wrong: The diary provides a 50% rune bonus, which adds ~9-10k per chest. Over 100 chests, that's nearly 1M gp lost. Many new players skip the diary because it requires some quest/skill investment (e.g., 70 Prayer for Piety, completion of Haunted Mine). However, the diary pays for itself in ~30-40 chests.
✓

Correct approach:

Complete Morytania Hard Diary before committing to Barrows as a moneymaker. The requirements are achievable for mid-level accounts (base 70s in combat stats). Use our diary completion guide to unlock this massive profit boost. If you're doing Barrows without the diary, you're leaving 500k+ gp/hour on the table.
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Killing all monsters in the tunnels to 'maximize loot'

Why it's wrong: This is a common misconception. Players think more kills = better loot. In reality, exceeding 1,012 Reward Potential dilutes the drop table with bolt racks (worth ~2-3k each) and loop/tooth halves (low value). This reduces your EV per chest because you're less likely to roll higher-value runes and more likely to get junk.
✓

Correct approach:

Kill exactly enough monsters to reach 1,012 potential, then open the chest. The optimal method: kill all 6 brothers (874 potential) + 2 skeletons (69 each) = 1,012. Use RuneLite's Barrows plugin to track potential in real-time. Some players kill 1 bloodworm instead of 1 skeleton—both work. Efficiency-focused players memorize monster spawns to hit 1,012 with minimal time spent in tunnels. See our efficiency guide.
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Using EV/chest to compare profitability without factoring in run time

Why it's wrong: Two players might have the same EV per chest (e.g., 50k), but if Player A completes runs in 75 seconds and Player B takes 120 seconds, Player A earns 2.4M/hour while Player B earns 1.5M/hour—a 60% difference. EV per chest is useful for understanding loot mechanics, but GPH is the true profitability metric.
✓

Correct approach:

Always calculate GPH (gold per hour) to compare moneymaking methods. Use the formula: GPH = EV_per_chest × (3600 / seconds_per_run). Optimize your route, gear, and prayer flicking to reduce run time. Top-tier players achieve 60-70 second runs, pushing GPH above 2.5M/hour. Our calculator lets you input your average run time to see realistic hourly profit. Track your times over 10 runs to get an accurate average—don't assume you're faster than you are.
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Selling all Barrows items immediately without checking set completion

Why it's wrong: While selling uniques immediately reduces price risk, some Barrows items (especially Dharok's set) are worth significantly more when sold as a complete set. For example, Dharok's full set might sell for 3M, but individual pieces total only 2.6M on GE. If you're close to completing a set, holding pieces can be profitable.
✓

Correct approach:

Check set bonuses before selling individual items. If you receive Dharok's helm and already have the platebody and legs from previous chests, hold them until you get the greataxe to sell the complete set for extra profit. Conversely, if you're unlikely to complete a set soon (e.g., you have 1 Guthan's piece), sell immediately to lock in prices. Use our set completion tracker to monitor which items you've received (note: this is a hypothetical link for demonstration—adjust to actual site resources if available).

Related Resources:

Glossary: Expected Value (EV) →Glossary: Union Probability →Understanding Reward Potential →Blog: EV vs GPH in OSRS →Blog: Variance & Dry Streaks →All OSRS Calculators →

Drop Rates & Unique Chance

This barrows loot calculator mirrors an OSRS drop rate calculator so you understand how many Barrows chest loot pulls it takes to land a unique. Both tunnel and crypt rolls are included, matching the in-game two-stage behaviour.

Two-stage probability model

Every chest checks kill count then rolls on the mutually exclusive unique table, meaning only one unique item can drop at a time. The calculator tracks both per-run and cumulative unique chances so you can plan when upgrades are likely.

Per-chest roll details

Rune, bolt rack, and unique rolls are simulated independently so OSRS loot calc theorycrafting stays accurate. Update the number of runs to watch the probability curve respond instantly.

Set items vs. other uniques

Dharok's, Ahrim's, Karil's, and the other Barrows sets share the same one-in-16 unique slot. The tool highlights relative weights so you can predict which set pieces or weapons you are most likely to complete next.

Common rewards

Death runes, chaos runes, bolt racks, and other staples are sourced from the latest loot tables. Toggle the Morytania diary bonus to include the additional bolt racks granted in the crypt.

Expected Value (EV)

Total EV and per-chest EV recalculate whenever you tweak run counts, price overrides, or the diary bonus. Wondering why EV per run stays constant? The answer lives in our FAQ explanation.

Price sources & updates

Default prices come from recent Grand Exchange snapshots, annotated in the data source widget. Override any item to plug in clan buy limits, personal margins, or Ironman valuations for your OSRS loot calc simulations.

GPH (Gold per Hour)

Combine EV, run time inputs, and supply costs to translate barrows unique drop rate math into practical gold per hour goals.

Time per run inputs

Enter your average chest time plus teleport and consumable costs to forecast net profit. Comparing PvE routes? Try the WoW Delves loot calculator for a horizontal look at other LootCalc tools.

Frequently Asked Questions

How is the expected value calculated?

EV = Σ(probability × item value) for all possible drops, using the mutual exclusion model for Barrows uniques.

What is the mutual exclusion model?

Only one Barrows unique can drop per chest. The calculator uses union probability: P(any unique) = 1 − P(no uniques).

Where do item prices come from?

Default prices are pulled from recent Grand Exchange data. You can override any item directly in the calculator.

Methodology, Assumptions & Sources

Updated: 2025-09-26. Model aligned with current Barrows chest tables; diary toggle supported.

Assumptions

  • Per-chest EV uses the official unique table with mutually exclusive rolls.
  • Run time and route density affect EV/hour (GPH) but not EV per chest.
  • Diary bonus toggles modify effective rates where applicable.

Formulas

  • EV: EV = Σ(valueᵢ × Pᵢ)
  • Union probability (any unique): P(any) = 1 − (1 − p)ⁿ — per independent chest roll
  • GPH: GPH = EV_per_chest × chests_per_hour

Worked Examples

Example: 64 runs, 90s/run

  1. Chests/hour ≈ 40 (3600 / 90).
  2. EV/chest = Σ(value × prob) from current table.
  3. GPH = EV/chest × 40; compare with diary toggle ON/OFF.

Data Sources

  • OSRS Wiki & official patch notes.
  • Community-verified tables; see page footer for links.

Caveats

  • Market prices fluctuate; snapshot timing matters.
  • Long dry streaks are possible even with good EV (variance).

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