PROGRESSION
Level & Cost Curve Calculator
Design XP and upgrade cost curves — linear, exponential, power — with JSON/PHP/CSV export.
CURVE DESIGNER
Build a progression curve
XP and upgrade costs are tuned independently — switch mode to edit each curve separately.
Cumulative total (levels 1→):
Level and cost curve guide
Progression is the heartbeat of an RPG: how much XP each level needs, how much a building upgrade costs, how the numbers grow from level 1 to the cap. Get the curve wrong and players either blast through content in an afternoon or stall out feeling cheated.
This calculator models XP and upgrade-cost curves with three growth shapes — linear, exponential, and power — over up to 1,000 levels, with a live preview, cumulative totals, and export to JSON, PHP, or CSV so you can drop the numbers straight into your game.
Choosing the right curve shape
The shape of your curve defines the feel of your game:
- Linear — start + add × (level−1). Every level costs the same as the last. Simple and predictable; works for short progressions or when you want steady, even pacing.
- Exponential — start × factor^(level−1). Costs grow multiplicatively: gentle early, brutal late. The classic "long tail" curve — great for MMO-style grinds and games with no level cap.
- Power — start × level^factor. Costs grow by a polynomial power. A middle ground: steeper than linear, gentler than exponential. Common in action RPGs and roguelikes.
Tip: In TempestKingdoms, building upgrades from level 1 to 25 use exactly this kind of exponential cost growth — a factor around 1.10–1.15 per level keeps early upgrades cheap while making max level a real achievement.
Reading the numbers
Per-level values are what a player pays to go from level N to N+1 (or the XP required to reach level N). The cumulative total is the full cost to max out — the number that tells you if your grind is reasonable.
A quick sanity check: with start 100 and factor 1.12 over 25 levels, the cumulative total is roughly 13,000 — meaning the last level alone (about 1,700) costs nearly as much as the entire first half of the game. That is the exponential curve doing its job.
Exporting to your engine
When the curve feels right, export it:
- JSON — drop into any engine, or feed straight into a data-driven table (Unity ScriptableObject, Godot Resource, etc.).
- PHP — paste directly into a PHP backend or config file for server-authoritative pricing.
- CSV — open in a spreadsheet, tweak values by hand, or import into a level-design tool.
- Copy JSON — for quick pasting into code without downloading a file.
Designing the grind
The best curves are tuned around two questions: how long should level 1→2 take (the first 5 minutes of fun), and how long should the final level take (the last stretch)? Exponential curves let you answer both with one factor. Power curves give you more control in the middle ranges.
Whatever shape you pick, validate against your playtest data — the curve is a starting point, not a verdict.
Frequently asked questions
What is the difference between XP and cost curves?
They are the same math, different labels: XP per level is what a player earns to level up; upgrade cost is what they pay to advance a building or skill. This tool does both with one toggle.
Which curve should I use?
Exponential for long grinds with a clear endgame (MMOs, upgrade systems), linear for short even progressions, power for a middle ground. Tune the factor with the live preview and cumulative total.
How do I use the exported data?
JSON drops into any engine or data table; PHP pastes into a backend config; CSV opens in a spreadsheet for hand-tuning.
What does the growth factor mean?
It is the multiplier applied each level. 1.12 means every level costs 12% more than the last. Higher factors make the curve steeper and the endgame grind longer.
Is my data sent anywhere?
No — the calculator runs entirely in your browser. Your curve data never leaves your device.
Privacy note: curve calculations, exports, and copying happen in your browser. Nothing is uploaded.