OSRS Target KC Calculator
How many kills does your goal actually take? Set a confidence level (50%, 90%, 99%) and see the kill count and hours behind it.
Popular uniques and pets, rates from the official OSRS Wiki.
Example: 4095 for an elysian sigil from the Corporeal Beast.
How sure you want to be of having the drop.
Used to estimate hours. Leave blank to skip time.
How to use the target KC calculator
- Pick your drop (or enter a rate) and choose how confident you want to be.
- See the kills needed for that confidence, not just the average.
- Optionally add your kills per hour to plan the real time cost.
How it works
Inverting the drop-chance formula gives the kills K needed for a probability p:
K = ln(1 − p) / ln(1 − 1/N) (rounded up) Worked example: a 1/512 drop needs about 355 kills for a coin-flip 50% chance, 1,178 kills for 90%, and 2,356 for 99%. The average is 512 kills, but roughly one player in three is still dry at the average, so planning around it underestimates real grinds.
Which confidence should you plan with?
50% is the honest coin flip: half of players finish before it, half after. 90% is a safer budget for planning supplies and hours; you only have a 1-in-10 chance of going past it. Anything above 99% mostly measures patience, not probability: that last percent costs almost as many kills as getting to 90% did.
Frequently asked questions
Why is 90% so much more than the average kill count?
Drop luck is heavily right-skewed. Most players finish early, but the unlucky tail stretches for a long time. The average (mean) sits at N kills, the median at about 0.69 × N, and reaching high certainty keeps adding kills forever; 100% is never reached.
Does my existing KC count toward the target?
Yes. The table assumes starting from zero, but your chance accumulates over every kill you've ever done at that rate. Use the drop chance calculator with your current KC to see where you stand.
What if my kill rate changes (better gear, slayer tasks)?
Only the hours estimate depends on kills/hour; the kill counts are fixed by the drop rate. Recalculate with your realistic long-run kill rate, including banking and respawn time.
Does the calculator account for boosted or pity rates?
No; it uses the flat rate you enter. Some content (like certain pets on Slayer tasks, or content with bad-luck mechanics) differs; check the notes in the preset list and the OSRS Wiki page for your boss.
Can I use this for pets?
Yes, the presets include every boss pet rate. The pet chance calculator is the same math with the pet list up front.
Related calculators
Built and maintained by the OSRSCalc founder · Drop rates verified against the official OSRS Wiki on 2026-09-30 · Page last updated 2026-09-30
See the formulas and methodology · Spotted a wrong rate? Tell us · Everything runs in your browser - nothing you enter leaves your device.