Pick the structures you plan to attack, and get the exact boulders, stone, mangonels and estimated time to bring them down — using real structure HP and in-game boulder damage.
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These are estimates — use them for planning, not as exact numbers.
The tool gives you a solid baseline for how many boulders, mangonels and roughly how much time and gold a siege will cost. Real fights have moving parts it can’t know: travel and setup, defenders repairing or fighting back, server lag, random defence ticks, terrain and line of sight. Leaders should take this baseline and add their own buffer time and judgement for everything else on the day.
Add as many of each type as you'll run at once. Total firing = static + movable; each fires 100 boulders then dies.
Add a target
Structure
Tier
Defence %
Current HP %
Quantity
Tick “Under construction” if the structure is still being built/upgraded — then its defence scales with current HP and it gets no supply-storehouse buff. A finished structure always keeps its full defence regardless of HP.
Save your attack plan and load it again later (free account).
My saved siege plans
Total boulders
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Stone needed
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500 stone / boulder
Mangonels needed
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100 boulders each
Firing time
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Mangonel build time
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Total siege time
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build + firing
Mangonel cost
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How this is calculated.
Damage per boulder = 52,000 × (1 − effective defence). For example: 0% def = 52,000, 50% = 26,000, 80% = 10,400, 95% = 2,600, and 100% def takes 0 (immune).
A finished structure always keeps its full defence no matter how low its HP is. A structure that’s under construction or upgrading instead has effective defence = capped max defence % × current HP %, which falls as its HP drops, and it can’t gain the supply-storehouse buff. While under construction a structure can never have more than 80% defence — that’s a hard limit for every structure. Some structures/tiers have an even lower cap (for example a Guard Tower is capped at 50% at T1 but 80% at T3). We’ve added the lower caps we’ve confirmed; where a specific lower cap hasn’t been verified yet, the 80% ceiling still applies and the target is marked in red (“lower cap not tested”) so it can be checked in-game.
Slash and pierce do nothing to structures — only blunt (mangonel boulders) counts.
Each mangonel fires 100 boulders, and each boulder costs 500 stone.
Time assumes ~7 seconds per shot (5s pull + 1s fire + 1s stun) plus your lag setting, divided across the mangonels firing.
Structure HP comes from the build database (cumulative per tier).
Engineers: mangonels are built by hammering — each mangonel has 10,000 HP and every swing adds HP (20 per swing with no skill is the minimum). Swings per mangonel = 10,000 ÷ HP per swing, build time = (swings × seconds per swing) ÷ speed multiplier, then ÷ number of engineers building in parallel. Any engineer with 100 advanced engineering builds 5–7× faster (it’s the skill, not the race — Oghmir aren’t special here). This only affects building the mangonels. Total siege time = build time + firing time.
Reality check: in-game defence drifts on random server ticks (roughly ±9% every ~15 min) and decaying structures lose HP over time, so treat the time as a planning estimate, not a stopwatch.