Flipping Basics

The Grand Exchange (GE) is OSRS's central marketplace where players post buy and sell offers. When a buy offer meets or exceeds a sell offer's price, a trade executes automatically. Each account has 8 GE slots (or 3 for free-to-play).

Critically, the GE is a dark order book — you cannot see other players' pending offers. There is no Level 2 data showing bid/ask depth. You can only observe completed trades through the OSRS Wiki Prices API, which reports the latest high/low prices and volumes at 5-minute intervals.

This means price discovery relies on “instant buy” (buying at a high price to fill immediately against the lowest sell offer) and “instant sell” (selling at a low price to fill against the highest buy offer). The gap between these two prices is the current margin.

A flip exploits the spread between what buyers are willing to pay and what sellers are willing to accept. The process:

1. Instant buy one item at high price to discover the current sell-side price.
2. Instant sell one item at 1 GP to discover the current buy-side price.
3. Calculate your margin: margin = sell_price - buy_price - tax.
4. If the margin is positive and sufficient, place a bulk buy offer at the discovered buy price, then relist at the sell price.

The key insight: instant buy gives you the high price (what you'd pay), and instant sell gives you the low price (what you'd receive). You want to buy at the low and sell at the high.

Jagex introduced a 1% GE tax in 2022 as a gold sink. In May 2025, this was raised to 2%, capped at 5,000,000 GP per transaction. The tax is deducted from the seller's proceeds.

The tax formula: tax = min(sell_price * 0.02, 5,000,000). Items selling for 250M GP or above hit the cap and are taxed at a flat 5M, making them proportionally cheaper to flip.

The 2% rate killed many mid-tier flips. Items in the 100–10K GP range were hit hardest — their margins often sat below 2% already. At least 28 previously profitable items became unviable after the increase. Penny items (under 100 GP) are effectively immune since the minimum tax rounds down to 0 or 1 GP.

Every item has a 4-hour buy limit — the maximum quantity you can purchase from the GE in a rolling 4-hour window. Common items like runes may have limits of 13,000+, while rare items may be limited to 8 or fewer.

Buy limits are the primary constraint on GP/hr. Even a high-margin item is worthless if you can only buy 8 per 4 hours. Factor this into calculations:

fill_hours = buy_limit / (daily_volume / 24)

If fill_hours is much less than 4, the item trades actively enough to fill your limit. If fill_hours exceeds 4, you may not even fill your buy limit within the window, reducing effective GP/hr.

Research on 367+ days of GE data shows that margins are surprisingly persistent. A 7-day lookback of an item's margin predicts the next day's margin with roughly 80% accuracy. This means that if an item has been consistently profitable over the past week, it is likely to remain profitable tomorrow.

This persistence is driven by structural factors: buy limits, GE tax, and the dark order book create friction that prevents margins from being arbitraged away instantly. Unlike real-world financial markets with high-frequency trading, OSRS margins can persist for days or weeks.