Stamina Refill Calculator

Stamina — also called energy, resin, sanity, AP, or action points depending on the game — is the universal gating resource in modern mobile and gacha games. Developers use it to pace progression, encourage daily check-ins, and create a reason to return to the game throughout the day rather than binge-playing until content is exhausted.

In most games, stamina regenerates automatically over time at a fixed rate per hour or per minute. When you run a dungeon, sweep a stage, farm materials, or complete a boss run, the activity costs a set amount of stamina. Once your stamina pool hits zero you either wait for it to refill naturally, spend a premium refill item, or use in-game currency to purchase a top-up.

Understanding how stamina mechanics work is one of the most underrated skills in mobile gaming strategy. Players who master their stamina cycle can farm the same content as spenders while spending far less — or nothing at all — on refill items. The core insight is simple: stamina sitting at its maximum cap is stamina being wasted. Every minute your pool is full, the regen system is producing nothing for you. Efficient players time their play sessions to arrive just as their stamina is full, drain it completely, and log off — maximising every point the game gives them for free.

This stamina refill calculator handles the full picture: regeneration time to any target, time to hit your maximum cap, how many runs you can do right now, the exact stamina deficit for a planned session, how many refill items you need, and what that will cost. It also warns you when you are overflowing so you can act before you waste free regen.

The calculator uses a small set of precise formulas drawn directly from mobile game mechanics. Each result follows straightforwardly from your inputs.

Regeneration time to a target stamina value: divide the stamina needed by your hourly regeneration rate, then multiply by 60 to convert to minutes.

Time to reach full cap: same formula applied to the gap between your current stamina and your maximum.

Stamina deficit for planned runs: the total stamina your run plan requires minus what you currently hold, floored at zero (you cannot have a negative deficit).

Refills needed: the deficit divided by the stamina each refill provides, rounded up — you cannot use a fraction of a refill item.

Total refill cost: the number of refills multiplied by the cost per refill in whatever currency your game uses (primogems, crystals, gems, orbs, etc.).

While the underlying mathematics is identical across titles, each game brands and tunes its stamina system differently. Knowing the numbers for your specific game lets you plug exact values into this calculator and get perfectly accurate results.

Genshin Impact uses Original Resin, capped at 200, regenerating 8 per hour (1 every 8 minutes). A full refill from 0 takes exactly 25 hours. Each resin refill item (Fragile Resin) restores 60 resin; purchased top-ups via Primogems cost 160 each for the first two daily replenishments, rising to 320 for the third and beyond. Burning resin efficiently is a top priority for free-to-play Genshin players.

Honkai: Star Rail calls its stamina Trailblaze Power, capped at 240, regenerating 6 per hour. A Condensed Aether acts as a 2x efficiency multiplier item rather than a direct refill.

Epic Seven uses Energy capped at 150, with a 1 per 5 minutes regen (12 per hour). Stage runs typically cost between 6 and 12 energy, so a full cap lasts a meaningful session before needing to refill.

AFK Arena uses Fast Rewards that act similarly, and many strategy RPGs use a comparable ticket or AP system. Battle Chasers: Nightwar, while a console title, popularised the stamina-for-dungeon-runs format that mobile games later adopted at scale.

Regardless of the skin, the underlying formula is the same. Enter your game's specific cap, current value, and regen rate to get precise results every time you open this stamina refill calculator.

The single most common efficiency mistake in mobile gaming is letting your stamina sit at its maximum cap. When your stamina is full, every unit of regeneration the game would have given you is silently discarded. Most games do not bank overflow — your cap is a hard ceiling, and regen simply stops (or is wasted) until you spend some.

The calculator flags this situation with an overflow warning and shows how much stamina you are wasting per hour. If your regen rate is 8 per hour and your stamina is capped, you lose 8 free stamina every hour you leave it untouched. Over a weekend that could represent dozens of dungeon runs you never got to take.

The practical solution is to play until your stamina is fully or nearly depleted before logging off, and to return when your stamina is close to cap — not necessarily when it is exactly full. The Stamina Forecast panel in the calculator shows your projected stamina after 1 hour and 8 hours, which is ideal for scheduling your next session. If you plan to sleep 8 hours, check whether your pool will cap before you wake up. If it will, consider draining it a bit more before bed, or use a natural regen timer alarm so you can do a quick farming session at the midpoint.

Some games mitigate overflow by allowing stamina to exceed the cap temporarily when awarded by events or log-in bonuses, storing it as "overcap" stamina above the displayed maximum. In those cases, the effective ceiling is higher and you have a larger buffer before waste begins. Always check your game's specific rules — this calculator uses the cap you provide, so enter your effective overcap value if your game supports it.

Deciding whether to spend premium currency on stamina refills is one of the highest-leverage economic decisions in any mobile game. The answer almost always points toward restraint: in most gacha games, the premium currency used for refills (primogems, crystals, gems) is the same currency used to pull on banners for new characters. Spending it on stamina means fewer pulls, which can set your roster progress back further than the stamina gain helps.

A useful rule of thumb in the Genshin Impact community is to treat 160 primogems as worth roughly 1 pull (0.625 pulls after exchange rate), so a single resin refill costs about two-thirds of a banner wish. Two daily refills per day for 30 days would consume roughly 9,600 primogems — equivalent to about 60 wishes, or a meaningful fraction of a standard 90-pull pity cycle.

Better strategies for free-to-play players include:

• Spending all natural stamina before each sleep cycle to avoid overnight overflow waste.
• Setting a phone alarm or using the forecast output from this calculator to wake for a mid-night stamina drain when farming is critical.
• Prioritising content with the best stamina-to-reward ratio — usually the highest-tier dungeons or weekly bosses.
• Using event-granted free refills first before ever touching purchased ones.
• Accepting that daily natural regen is finite. A sustainable pace is generally better than panic-farming with paid refills.

Use the refill cost fields in the calculator to model exactly what a burst farming session will cost in your game's currency, then weigh that against what else you could spend it on.

The calculator is divided into three input panels and two output panels. Here is a step-by-step walkthrough to get the most accurate results for your situation.

Current Stamina panel: Enter your exact current stamina value and your maximum cap. Then set your regeneration rate in stamina per hour — check your game's wiki or loading screen tips if you are unsure. The bar display turns red if you are at or above cap, which triggers the overflow warning.

Activity Planning panel: Enter how much stamina each farming run costs (check the stage select screen in your game) and how many runs you want to complete in your session. The calculator immediately shows how many runs you can do right now and the total stamina the full plan requires.

Refill Options panel: Enter the stamina each refill item restores and its cost in premium currency. This drives the refills-needed and total-cost outputs.

Time to Full: The prominent result at the top of the output column tells you how many hours and minutes until your stamina reaches its cap from your current value, and the estimated clock time of that moment. Use this for session planning.

Stamina Forecast: Shows what your stamina will be 1 hour and 8 hours from now (capped at max). Use the 8-hour projection to determine whether your stamina will overflow while you sleep, so you can adjust your pre-bed farming session accordingly.