ToolFeather

OSRS Dry Calculator

Find out exactly how unlucky you are — enter a drop rate and how many kills you've done to see your chance of the drop by now, and the odds of going this dry.

OSRS Dry Calculator

Assumes an independent 1/rate chance each kill. 🔒 Calculated in your browser.

🔒 Nothing you enter is sent anywhere or stored. All processing happens in your browser.

Features

Tells you how dry you really are

See the exact percentage of players who would still be without the drop at your kill count — the honest 'how unlucky am I' number.

Any drop rate, any count

Works for a 1/16 clue step or a 1/5000 pet; enter the rate and your kills.

Expected kills too

Shows the average number of kills for the drop (the drop-rate denominator), so you know where you stand.

Instant and private

Recalculates as you type; nothing is uploaded.

How it works — in four simple steps

No signup, nothing to install — it all runs in your browser.

Step 01

Enter the drop rate

Type the denominator — for a 1/128 drop, enter 128.

Step 02

Enter your kill count

Type how many kills or attempts you've done.

Step 03

Read your odds

See your chance of the drop by now and the chance of still being dry.

Step 04

Feel better (or worse)

Compare your count to the expected kills to see how (un)lucky you are.

How it works

Every OSRS drop is an independent roll: at a drop rate of 1 in d, each kill has a 1/d chance of the item. So after n kills, your chance of having seen at least one is 1 − (1 − 1/d)ⁿ, and the chance of still being dry is (1 − 1/d)ⁿ. That second number is the real measure of how unlucky you are.

Enter the drop rate and how many kills or attempts you've done, and this calculator shows your chance of the drop by now, the chance a player would still be dry at your count, and the expected number of kills (which equals the drop-rate denominator). A common surprise: even at exactly the drop rate, about 37% of players are still dry — dropping is not a pity timer.

It's all computed in your browser. Note it assumes a flat, independent rate; a few bosses use a different system, but the vast majority of drops work exactly like this.

Examples

1/128 drop, 128 kills → 63.4% chance by now, 36.6% still dry.
1/5000, 5,000 kills → still a 36.8% chance of being dry — that's normal, not a bug.

Frequently asked questions

How does the OSRS dry calculator work?
It uses the probability of at least one success in n independent trials: 1 − (1 − 1/d)ⁿ, where d is the drop-rate denominator and n is your kills. The 'still dry' figure is (1 − 1/d)ⁿ.
If the drop is 1/128, am I guaranteed it by 128 kills?
No. At exactly the drop rate you have about a 63% chance of having seen it, which means roughly 37% of players are still dry at that point. Drops have no pity timer.
What does 'expected kills' mean?
It's the average number of kills per drop, which equals the drop-rate denominator (1/d → d kills on average). Plenty of players get it faster or slower.
Is going 2× or 3× the drop rate normal?
It happens: at 2× the rate about 13.5% of players are still dry, and at 3× about 5%. Unlucky, but far from impossible.
Does this work for every drop?
It assumes a flat, independent chance each kill, which is how the large majority of OSRS drops work. A few bosses use special mechanics, so treat those as approximate.