Gems are the primary currency in Universal Tower Defense Z. You use them to summon new units, expand team slots, purchase Trait Rerolls, and acquire evolution materials. Every progression system in UTDZ depends on having enough Gems, making efficient Gem farming one of the most important skills to master. This guide covers all Gem farming methods ranked by efficiency, provides detailed strategies for each method, and offers an optimal daily farming routine that maximizes your Gem income per hour of playtime.
Gem Farming Methods Ranked by Efficiency
| Method | Gems/Hour | Effort | Requirements | Best For |
|---|---|---|---|---|
| Story Mode (Ch.5+) | 300K-540K | Active | Evolved S-tier team | Active farming sessions |
| Active Codes | 100K+ (instant) | None | Just redeem | All players — instant boost |
| Challenges (daily 3x) | 50K | Active | Balanced team | Daily routine |
| AFK Infinite Mode | 80K | Passive | Sustainable team | Overnight/sleep |
| Daily Quests | 30K | Active | Quick completion | Daily routine |
| Weekly Quests | 15K/hr equiv. | Active | Various tasks | Weekly completion |
| Events | 20K-100K/hr | Active | Event-specific team | Limited time periods |
The fastest method is Story Mode replay with an optimized team, yielding over 540K Gems per hour at the highest chapters. However, AFK Infinite Mode provides passive income that requires zero active playtime, making it the most time-efficient method overall.
Story Mode Gem Farming — The Active Method
Story Mode replay is the highest-yield active farming method in UTDZ. Higher chapters provide more Gems per clear but take longer:
| Chapter | Gems/Clear | Clear Time | Gems/Hour | Team Power Needed |
|---|---|---|---|---|
| Ch.3 | 30K | 5 min | 360K | Mid-game evolved team |
| Ch.5 | 75K | 10 min | 450K | S-tier evolved + traits |
| Ch.7 | 120K | 15 min | 480K | Etherealized S-tier team |
| Ch.9 | 180K | 20 min | 540K | Fully built endgame team |
Optimal Chapter Selection
| Your Team Stage | Best Chapter | Why |
|---|---|---|
| Early game (no S-tier) | Ch.3 | Fast clears = best Gems/min |
| Mid game (1 S-tier evolved) | Ch.5 | Best Gems/hour-to-difficulty ratio |
| Late game (S-tier + etherealization) | Ch.7 or Ch.9 | Highest absolute Gems/hr |
Chapter 5 is the sweet spot for most players because it provides 450K Gems/hour with a team that most mid-game players can field. Chapter 9 requires a fully built team and the per-hour rate is only marginally higher.
Story Mode Team for Gem Farming
| Role | Unit | Trait | Why |
|---|---|---|---|
| AoE DPS | Joyful Captain | Ruler or Sacred | Clears waves fastest |
| Farm | Gold Farmer | Fortunate | +20% income = extra Gems |
| Support | Spirit Buffer | Astral | Buffs team for faster clears |
| Flex 1 | Ancient Mage | Sacred | Long-range coverage |
| Flex 2 | Pirate King | Prodigy | Single-target boss damage |
| Flex 3 | Any fast unit | Any | Wave cleanup |
Always include a Farm unit with Fortunate trait when farming Gems. The +20% income bonus compounds over every clear, adding 15-20K extra Gems per hour. Over a month of daily farming, this adds up to millions of extra Gems.
AFK Gem Farming — The Passive Method
AFK farming in Infinite Mode provides passive Gem income while you are away from the game. This is the most time-efficient method because it requires zero active play:
| Duration | Gems Earned | Team Requirement | When to Run |
|---|---|---|---|
| 4 hours | 320K | Mid-game sustainable team | Afternoon break |
| 8 hours (overnight) | 640K | Strong sustainable team | Before bed |
| 12 hours | 960K | Fully etherealized team | Long AFK periods |
AFK Farm Team Composition
| Slot | Unit | Trait | Why |
|---|---|---|---|
| DPS | Joyful Captain | Sacred | Sustained AoE for wave clear |
| Farm | Gold Farmer | Fortunate | +20% passive income |
| Support | Spirit Buffer | Astral | Team buff maintenance |
| Tank | Shield Guardian | Sacred | Survivability |
| DPS 2 | Ancient Mage | Sacred | Long-range backup |
| Flex | Any high-HP unit | Any defensive | Survival padding |
Test your AFK team by running Infinite Mode for 30 minutes while watching. If your team survives wave 50+ with full HP, it can survive overnight (8+ hours). See our game modes guide for detailed Infinite Mode strategies.
Daily Gem Farming Routine
| Time | Activity | Gems | Time Spent |
|---|---|---|---|
| Morning | Redeem active codes | 100K+ (instant) | 2 min |
| Morning | Daily Quests | 30K | 10 min |
| Morning | 3x Challenges | 50K | 23 min |
| Afternoon | Story Mode farming (2 hours) | 600K-1.08M | 2 hr |
| Before bed | Start AFK Infinite | 640K (overnight) | 2 min |
| Daily Total | 1.42M-1.9M+ | ~3 hr active |
This routine provides approximately 1.5-2 million Gems per day with about 3 hours of active playtime. Over a week, that is 10-14 million Gems — enough for 2-3 featured banner pity pulls. For weekly optimization, see our daily routine guide.
Gem Spending Priority
| Priority | Use | Gems Required | Value | Why |
|---|---|---|---|---|
| 1 | Featured banner pity | 5000 | Guaranteed S/A-tier unit | Best Gem-to-power ratio |
| 2 | Team slot expansion | 500-1500 | 5→6 team slots | More team flexibility |
| 3 | Unit storage expansion | 200-500 | More unit capacity | Collection management |
| 4 | Trait Rerolls | 1 per reroll | RNG-dependent | Only after core needs |
| 5 | Evolution materials | 1000+ | Available via gameplay | Last resort — farm instead |
Never spend Gems randomly on standard banner pulls. The expected value is much lower than saving for featured pity, which guarantees a high-quality unit. See our summoning guide for optimal pull strategy.
Monthly Gem Income
| Source | Monthly Gems | Active Time |
|---|---|---|
| Story Mode (1hr/day) | 9M+ | 30 hr |
| AFK Infinite (8hr/night) | 19.2M+ | Passive |
| Challenges + Quests | 2.4M | 16 hr |
| Codes | 100K+ | Instant |
| Total | 30.7M+ | ~46 hr active |
A dedicated free-to-play player can farm over 30 million Gems per month. This funds 6+ featured pity pulls, ensuring regular access to S-tier and Legendary units.
Summer Currency Farming
Summer Currency is a seasonal resource earned alongside Gems during the Summer Event:
| Stage | Summer Currency/Hour | Difficulty | Team |
|---|---|---|---|
| Summer Stage 1 | 2K | Easy | Any team |
| Summer Stage 2 | 5K | Medium | S-tier team |
| Summer Stage 3 | 10K | Hard | Full built team |
Summer Currency purchases exclusive event items including the Summer Event unit (50K currency). Prioritize the limited unit purchase — it may not return after the event. Check our codes page for bonus Summer Currency from active codes.
Gems per Hour — Detailed Efficiency Comparison
Every farming method in UTDZ has different efficiency, effort requirements, and accessibility. This detailed comparison helps you choose the best method for your situation:
| Method | Gems/Hour | Effort | Level Required | Team Required | Sustainability |
|---|---|---|---|---|---|
| Story Mode (speed run) | 300K-400K | Active | Any | AoE DPS team | Infinitely repeatable |
| Story Mode (first clear) | 200K-300K | Active | Any | Any team | One-time per chapter |
| Challenge Runs | 150K-200K | Active | Level 10+ | A-tier team | 3 per day |
| Raid Runs | 100K-150K | Active | Level 10+ | Co-op team | Limited by Raid tickets |
| Infinite AFK | 60K-100K | Passive | Level 5+ | AFK team | 24/7 sustainable |
| Daily Quests | 120K (15 min) | Active | Any | Any team | Daily reset |
| Weekly Quests | 100K (30 min) | Active | Any | Any team | Weekly reset |
| Codes | 210K+ (instant) | Instant | Any | None | Limited availability |
AFK Farming Detailed Setup
| Setup | Gems/Hour | Monthly Gems | Setup Cost | Notes |
|---|---|---|---|---|
| Basic AFK (1 DPS) | 60K | 4.3M (8hr/day) | Free | Minimum viable |
| + Farm (Fortunate) | 72K | 5.2M | 100 Rerolls | +20% income |
| + Support | 80K | 5.8M | Free | Buff increases clear speed |
| + 2nd Farm | 96K | 6.9M | 200 Rerolls | +40% income |
| Full optimized | 100K+ | 7.2M+ | Full investment | Maximum passive income |
Gem Spending Priority Guide
How you spend Gems is just as important as how you earn them. Here is the definitive spending priority:
| Priority | Spend On | Gem Cost | Expected Return | ROI Rating |
|---|---|---|---|---|
| 1 | Featured banner pity (S-tier) | 500-750/pull | Guaranteed S-tier unit | ★★★★★ |
| 2 | Evolution materials for S-tier | 100K-700K total | +200% base stats | ★★★★★ |
| 3 | Unit slot expansion | 500-1000/slot | More team flexibility | ★★★★ |
| 4 | Standard banner (A-tier) | 250/pull | A-tier units | ★★★ |
| 5 | Cosmetics | Varies | Visual only | ★ |
Gem Spending Mistakes to Avoid
| Mistake | What Players Do | Correct Approach | Gems Wasted |
|---|---|---|---|
| Random standard pulls | Pull standard banner hoping for S-tier | Save for featured banner pity | 100K+ Gems |
| Buying cosmetics early | Spend Gems on skins before building team | Only buy cosmetics after team is built | Variable |
| Skipping Farm investment | Not investing in Farm unit Fortunate | Fortunate Farm increases all future income | 3.8M+/month |
| Over-spending on Evolution | Evolving C-tier units | Only evolve S/A-tier units | 200K+ per wasted evolution |
| Ignoring code rewards | Not redeeming codes before spending | Always redeem free codes first | 210K+ Gems |
Weekly and Monthly Gem Income Calculator
| Source | Daily Income | Weekly Income | Monthly Income |
|---|---|---|---|
| Story Mode (1hr/day) | 300K | 2.1M | 9M |
| Daily Quests (15min) | 30K | 210K | 900K |
| Challenges (3/day) | 50K | 350K | 1.5M |
| AFK Infinite (8hr) | 80K | 560K | 2.4M |
| Codes (average) | ~7K | ~50K | 200K+ |
| Weekly Quests | — | 50K | 200K |
| Total | 467K | 3.32M | 14.2M+ |
With a Fortunate Farm unit, all of these figures increase by 20%, adding another 2.8M+ Gems per month. This demonstrates why the Fortunate trait is the single most impactful early-game investment.
Frequently Asked Questions
What is the fastest way to get Gems? Redeem active codes first for an instant 100K+ Gem boost. Then farm Story Mode at 300K+ Gems per hour with an optimized team. AFK Infinite Mode provides passive 80K Gems/hour overnight.
Should I save Gems or spend them? Save for featured banner pity (5000 Gems per guaranteed pull). Random spending on standard banners has lower expected value. Only spend on other items after securing your next pity pull.
Can I AFK farm overnight safely? Yes, if your team passes the 30-minute survival test in Infinite Mode. Use a sustainable team with Farm (Fortunate) + Support (Astral) + AoE DPS. See our AFK farming guide for team builds.
How much is a Gem worth in terms of Robux? UTDZ is free-to-play and Gems can be farmed entirely through gameplay. Purchasing Gems with Robux is never necessary for competitive progression. The optimal strategy is to farm 30M+ Gems per month for free.