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Area = s², wheresis side.Perimeter = 4sDiagonal = s√2⇔s = d / √2
All calculations are performed in base SI units internally and converted to your selected output units.
- Length inputs accept non‑negative values; blank fields are treated as zero.
- Choose Measurement Mode to switch between side or diagonal entry.
- Decimals are clamped between 0 and 8 to prevent misleading precision.
- Cost estimate multiplies area by your chosen rate in the selected area unit.
| Unit | Value |
|---|---|
| m² | — |
| cm² | — |
| mm² | — |
| in² | — |
| ft² | — |
| yd² | — |
- Inputs are non‑negative.
- Active mode is respected.
- All computed values are finite.
1) How do I calculate a square’s area from the side?
Use Area = s². Enter the side length and pick its unit. The calculator converts internally and returns the area in your chosen output unit.
2) How do I calculate using the diagonal?
Select Diagonal length mode. The side is computed as s = d / √2, then the same formulas apply for area and perimeter.
3) What units are supported?
Lengths: m, cm, mm, in, ft, yd. Areas: m², cm², mm², in², ft², yd². You can set any output area unit independently of the input unit.
4) Why are decimals limited to 0–8?
Limiting the number of decimals avoids spurious precision and keeps the layout readable, while still supporting engineering‑grade rounding when needed.
5) How is the cost estimate computed?
It multiplies the computed area (in the selected area unit) by your specified price per unit area. Leave the field empty if you don’t need cost estimation.
6) Can I export results?
Yes. Use the Download CSV button to save the current inputs, results, and a full area conversion table to a spreadsheet‑friendly file.
7) What if I only know perimeter?
If you know perimeter P, then side is s = P/4. Enter that side value to compute diagonal and area.
8) Is this suitable for tile or paint estimates?
Yes. Choose the output unit that matches supplier pricing, enter your rate, and the cost estimate will reflect the surface area of the square.