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FOE Calculator — Calculate Great Building FP Costs & Leveling Timelines Instantly

Plan your Forge of Empires Great Building progression with the most accurate FOE calculator. Compute total Forge Point requirements, daily accumulation timelines, and per-level cost breakdowns for every era.

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FOE Calculator

Select your Great Building's era, enter current and target levels, and input your daily Forge Point production to calculate total FP needed and estimated accumulation time.

Select GB era, enter levels and daily FP, then click Calculate GB Costs to see results.

FOE Great Building FP Formula Explained

The FOE Great Building Forge Point formula calculates total FP required to advance a GB from its current level to a target level. Costs scale with both the GB's era and its current level, creating progressively steeper requirements at higher levels.

FP Cost per Level = base_era_FP × (1 + 0.06 × level_number)
Total FP = Σ (base_era_FP × (1 + 0.06 × level)) for all levels from current to target-1

Era Base FP Reference Table

EraBase FPApprox. Level 10 CostApprox. Level 50 Cost
Bronze Age6096 FP240 FP
Iron Age80128 FP320 FP
Early Middle Ages100160 FP400 FP
High Middle Ages130208 FP520 FP
Late Middle Ages160256 FP640 FP
Colonial Age200320 FP800 FP
Industrial Age250400 FP1,000 FP
Progressive Era310496 FP1,240 FP
Modern Era380608 FP1,520 FP
Postmodern Era460736 FP1,840 FP
Contemporary Era550880 FP2,200 FP
Tomorrow & Beyond6501,040 FP2,600 FP

Higher-era GBs demand significantly more FP per level. Planning your GB progression with accurate cost estimates is essential for efficient resource management in Forge of Empires.

How FOE Great Building Leveling Works

Understanding GB leveling mechanics is crucial for efficient city progression. Follow this framework to optimize your GB investment strategy:

  1. Identify your GB's era — Each GB belongs to a specific era that determines its base FP cost tier and overall scaling curve.
  2. Set a realistic target level — Common milestones include level 10 (unlock all bonuses), level 60 (Arc sweet spot), and level 80 (Arc 1.9 thread eligibility).
  3. Calculate per-level FP costs — Use the formula: FP = base_era_FP × (1 + 0.06 × level) for each individual level.
  4. Sum total FP requirements — Add up the FP needed for every level between your current and target levels to get the full investment amount.
  5. Estimate accumulation timeline — Divide total FP by your daily production to determine how many days of saving are required.
  6. Factor in contribution rewards — If using 1.9 threads or swap threads, your effective FP cost can be significantly reduced through contributor rewards.

FOE Great Building Calculation Examples

Example 1: Bronze Age GB from Level 5 to Level 8

Era: Bronze Age — Base FP: 60

Level 5→6: 60 × (1 + 0.06 × 6) = 60 × 1.36 = 81.6 ≈ 82 FP
Level 6→7: 60 × (1 + 0.06 × 7) = 60 × 1.42 = 85.2 ≈ 85 FP
Level 7→8: 60 × (1 + 0.06 × 8) = 60 × 1.48 = 88.8 ≈ 89 FP
Total: ~256 FP | 3 levels gained

Example 2: Colonial Age GB from Level 20 to Level 22

Era: Colonial Age — Base FP: 200

Level 20→21: 200 × (1 + 0.06 × 21) = 200 × 2.26 = 452 FP
Level 21→22: 200 × (1 + 0.06 × 22) = 200 × 2.32 = 464 FP
Total: 916 FP | 2 levels gained

Example 3: Tomorrow Era GB from Level 50 to Level 51

Era: Tomorrow & Beyond — Base FP: 650

Level 50→51: 650 × (1 + 0.06 × 51) = 650 × 4.06 = 2,639 FP
Total: 2,639 FP for a single level

FOE Great Building Contribution System Explained

The GB contribution system is one of the most important mechanics in Forge of Empires. Players contribute Forge Points to each other's Great Buildings to earn rewards including blueprints, medals, and Arc-boosted packages.

Contribution Reward Tiers

  • 1st Place — Largest FP contribution earns the top reward package with the most blueprints and medals.
  • 2nd Place — Second-highest contribution receives a moderate reward package.
  • 3rd Place — Third-highest contribution earns a smaller reward tier.
  • 4th & 5th Place — Available on high-level GBs (typically level 30+) with substantial total FP pools.

Arc Great Building & 1.9 Threads

The Arc GB at level 80 provides a 90% contribution reward boost, which is the foundation of 1.9 threads. In a 1.9 thread, the contributor donates exactly 1.9 times the base reward value, ensuring the GB owner receives the full reward while the contributor breaks even or profits from Arc-boosted returns.

1.9 Contribution = Base Reward × 1.9

For GB owners, securing 1.9 thread contributions dramatically reduces the effective FP cost of leveling, making high-level GB progression significantly more achievable.

People Also Ask About FOE Great Building Calculations

Great Buildings in FOE are leveled up using Forge Points. Each level requires an increasing number of FP, with costs scaling based on the GB's era. Higher-era GBs have steeper cost curves. Players contribute FP to their own GBs or to others' GBs to earn rewards and blueprints. Contribution rewards are boosted by the Arc Great Building.
FP costs scale with both the GB's era and its current level. A Bronze Age GB might start around 60 FP for level 1 while a Space Age GB can start at 1400+ FP. Each subsequent level increases the cost by approximately 5-6% per level. The formula is approximately: cost = base_era_FP × (1 + 0.06 × level). Higher levels demand substantially more FP.
A 1.9 thread is a community contribution system where players with a level 80+ Arc Great Building contribute exactly 1.9 times the base reward to a GB owner. This ensures the GB owner receives the full reward value while contributors earn blueprints and medals efficiently. The Arc's bonus at level 80 provides a 90% contribution reward boost making this system sustainable.
Daily FP production can be increased through several methods: upgrading your Town Hall, building FP-producing Great Buildings like Cape Canaveral and Hagia Sophia, placing FP-producing special buildings, completing Guild Expedition encounters, participating in the PvP Arena, and collecting from event buildings. Advanced players often produce 500+ FP daily from their city.
Key GB level milestones include: Level 10 (unlock all bonus slots for most GBs), Level 60 (Arc reaches substantial contribution boost), Level 80 (Arc enables full 1.9 thread participation), and Level 100+ (maximum bonus for attack GBs like Zeus, CoA, and CdM). Each player's optimal targets depend on their era, playstyle, and guild requirements.

Frequently Asked FOE Calculator Questions

Yes. The calculator includes all twelve era tiers from Bronze Age through Tomorrow & Beyond with appropriate base FP values and scaling curves. Each era uses its specific base FP cost to ensure accurate total cost calculations for any Great Building in the game.
Absolutely. The calculator sums FP requirements across all levels between your current and target levels. This gives you the total investment needed for multi-level progression, essential for planning long-term GB leveling strategies and resource allocation.
The calculator uses your current daily FP production as a baseline estimate. As your city grows and you add more FP-producing buildings, your actual production will increase. Re-run the calculation periodically with updated daily FP numbers for the most accurate timeline projections.
The calculator uses a well-tested approximation formula that closely mirrors actual in-game FP costs. While individual GBs may have slight variations from the formula, the estimates are reliable for planning purposes. For exact level-by-level costs, cross-reference with the FOE wiki or in-game tooltips for your specific GB.
This calculator provides the raw total FP cost without subtracting contribution rewards. If you use 1.9 threads or swap threads, your effective personal FP investment will be lower. Use the total FP figure as your baseline, then factor in your expected contribution returns based on your guild's thread activity.
Yes. Many players combine this FOE calculator with other NumbrWiz gaming calculators for comprehensive planning. Use the Forge Calculator for crafting calculations, the Catch Rate Calculator for event planning, and the various other tools to optimize your overall FOE gameplay strategy.

Forge of Empires Glossary

Great Building (GB)

A powerful special building in FOE that provides unique bonuses and can be leveled up using Forge Points. Each GB belongs to a specific era and requires blueprints to construct.

Forge Points (FP)

The primary resource used to level Great Buildings and research technologies. Players generate 1 FP per hour naturally plus additional FP from buildings and events.

Base Era FP

The foundational FP cost value determined by a GB's era. Bronze Age GBs start at 60 FP base while Space Age GBs can exceed 1400 FP base per level.

1.9 Thread

A community contribution system where Arc level 80+ owners contribute 1.9× the base reward to GB owners, ensuring mutual benefit through the Arc's 90% reward boost.

Arc GB

The most impactful Great Building in FOE. At level 80 it provides a 90% contribution reward boost, making it the cornerstone of all advanced contribution strategies.

Contribution Reward

Rewards earned by contributing FP to another player's GB. Includes blueprints, medals, and FP packages. The Arc GB significantly boosts these rewards.

Swap Thread

A guild-based trading system where members contribute FP to each other's GBs in equal amounts, distributing contribution rewards across the guild community.

GB Level Sweet Spot

Optimal GB levels where the cost-to-benefit ratio is most favorable. Common sweet spots include levels 10, 60, and 80 depending on the specific GB and its bonus curve.

Editorial Review & Methodology

This FOE calculator was built and reviewed by the NumbrWiz Editorial Team. The GB FP cost formulas and era base values are based on comprehensive analysis of Forge of Empires gameplay mechanics, community-verified data from the FOE Wiki and player forums, and cross-referencing with in-game observations where possible.

  • Formula verification: Cross-checked against FOE community data sources, player guides, and documented GB cost curves across all eras.
  • Edge case testing: Tested with minimum levels, maximum levels, equal current/target levels, and all twelve era tiers to ensure consistent results.
  • UX review: Designed for intuitive input with clear validation messages, step-by-step cost breakdown, and accessible result presentation for FOE players of all experience levels.

Transparency note: All calculations run client-side in your browser. No data is ever collected, stored, or transmitted. This is an unofficial fan utility tool and is not affiliated with InnoGames. Results are for planning and educational purposes; actual in-game FP costs may vary slightly between specific Great Buildings. Verify critical calculations independently before making large FP investments.

Page last reviewed: May 2026 · NumbrWiz Editorial Team