Problem

Recharts' default tick generation frequently produces non-round, hard-to-read axis values like $6,000, $28,000, $51,000 instead of clean values like $0, $25,000, $50,000, $75,000, $100,000.

This is a long-standing issue (#2140, #777, #1164) that affects virtually every chart that uses numeric axes with auto-generated ticks. The standard workaround is to compute explicit ticks arrays and pass them manually — but this defeats the purpose of a charting library handling it automatically.

Root cause

getTickValuesFixedDomain() in src/util/scale/getNiceTickValues.ts doesn't produce aesthetically clean tick values when the domain is explicitly set. The main getNiceTickValues() does better but still struggles with tickCount respect.

D3's d3-scale.nice() solves this well by snapping to 1/2/5 multiples of powers of 10. The current Recharts algorithm attempts something similar but the results are often not "nice" in practice.

Proposed fix

I'd be happy to submit a PR improving getTickValuesFixedDomain() to:

1. Always start ticks at 0 when the domain includes 0
2. Use clean 1/2/2.5/5/10 step multiples (similar to D3's approach)
3. Respect tickCount more accurately
4. Maintain backward compatibility with existing tests

Here's a minimal version of the algorithm that works well in practice:

function niceTicks(dataMax: number, targetCount: number = 5): number[] {
  if (dataMax <= 0) return [0];
  const rawStep = dataMax / targetCount;
  const magnitude = Math.pow(10, Math.floor(Math.log10(rawStep)));
  const normalized = rawStep / magnitude;

  let niceStep: number;
  if (normalized <= 1) niceStep = 1 * magnitude;
  else if (normalized <= 2) niceStep = 2 * magnitude;
  else if (normalized <= 2.5) niceStep = 2.5 * magnitude;
  else if (normalized <= 5) niceStep = 5 * magnitude;
  else niceStep = 10 * magnitude;

  const niceMax = Math.ceil(dataMax / niceStep) * niceStep;
  const ticks: number[] = [];
  for (let v = 0; v <= niceMax; v += niceStep) {
    ticks.push(Math.round(v * 1e10) / 1e10);
  }
  return ticks;
}

Before/After

Before (current Recharts default):

• X axis: $6,000 $28,000 $51,000 $75,000 $100,000
• Y axis: $6,500 $13,000 $19,500 $26,000

After (with nice ticks):

• X axis: $0 $20,000 $40,000 $60,000 $80,000 $100,000
• Y axis: $0 $5,000 $10,000 $15,000 $20,000 $25,000 $30,000

Context

• Related: Problems with specifying domain as ['dataMin', 'dataMax'], the ticks are not calculated correctly, allowDecimals does not work, tickCount is not respected. #2140 (PavelVanecek mentioned fixing in Jul 2025), <YAxis/> Not Respecting allowDecimals and tickCount Prop when domain is set to non-int values #777, Floating point imprecision skews YAxis ticks #1164, [feature] initialTickValue and tickModulus axis properties #1052
• Aware of PR Rendered ticks in hooks #6990 (rendered ticks in hooks) — happy to coordinate timing
• We've implemented this workaround in multiple projects and it would be great to have it built into Recharts