Tools
Config-driven calculators and helpers—each tool doubles as an explainer page for search and sharing. Jump into a subject hub or scroll the full catalog.
By subject
Same grouping as your curriculum—e.g. chemistry calculators in one place.
All tools
Alphabetical list of published utilities Showing 385–432 of 564.
- formula calculator
Percentage calculator
What percent is a of b, or what is p% of n.
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Percentage error
Percent error from measured and accepted values.
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Percent yield calculator
Percent yield from actual and theoretical yield (same units—grams or moles).
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Perimeter calculator
Perimeter or circumference.
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Period from frequency
T = 1/f.
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Periodic trend (EN)
Compare Pauling electronegativity between two elements.
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Permutations (nPr)
n!/(n−r)!.
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pH and [H⁺] (bio context)
pH ↔ hydrogen ion molarity.
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pH calculator
pH from [H⁺] or [H⁺] from pH.
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Phenotype probability
Autosomal dominant/recessive with complete dominance from allele frequency p.
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pH from K_a calculator
Weak-acid pH from K_a and analytical concentration (common approximations).
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Photoelectric effect
K_max = hf − φ with φ in eV.
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Photosynthesis rate (toy index)
η × light × area placeholder.
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Phylogenetic trees (guide)
Pointer to proper tree software.
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Physics attempt analyzer
Accuracy and rough score from correct/wrong/skipped counts.
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Physics unit converter
Convert length, mass, time, speed, force, and energy via SI base factors.
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Planck equation (E = hf)
Photon energy from frequency.
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Plant growth rate
r = ln(M₁/M₀)/Δt on mass proxy.
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pOH calculator
pOH from [OH⁻] or [OH⁻] from pOH; optional pH at 25 °C.
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Poisson distribution calculator
PMF and CDF for Poisson(λ).
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Polynomial factorization (quadratic)
Factor ax²+bx+c over ℝ.
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Polynomial graph
Same engine as the polynomial function plotter.
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Polynomial solver (cubic)
One real root of ax³+bx²+cx+d by Newton.
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Population density
D = N / area.
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Power
P = W/t or P = F v cos θ.
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Power consumption
P = V I or P = E/t.
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Power in a circuit
P = IV, I²R, or V²/R.
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ppm ↔ mg/L
For dilute aqueous solutions using density ρ (g/mL).
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Present value calculator
Discount a future value to today.
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Pressure converter
atm, bar, and Pa.
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Pressure converter
Pa, atm, bar, mmHg, psi.
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Pressure (fluid, from force)
P = F/A.
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Prime checker
Test if n is prime (trial division).
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Prime factorization
Factor n ≥ 2 into primes.
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Prism calculator
Rectangular or triangular prism volume.
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Probability (favorable/total)
P = favorable outcomes / total.
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Process efficiency calculator
Mass or mole efficiency vs theoretical stoichiometry.
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Profit and loss calculator
% profit/loss on cost price.
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Projectile max height
H = (v₀ sin θ)² / (2g) above launch height.
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Projectile position
x(t), y(t) from v₀ and θ; no air resistance.
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Projectile range
Range on level ground: R = v₀² sin(2θ) / g.
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Projectile time of flight
T = 2 v₀ sin θ / g back to launch height.
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Proportion calculator
Solve a/b = c/d for one missing value.
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Protein molecular weight
Linear chain mass from residue masses.
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Protein sequence analyzer
Length and amino-acid counts.
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Protein structure (resources)
Pointer to AlphaFold and homology modeling.
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Punnett square (monohybrid)
AA, Aa, aa parents — offspring genotype ratios.
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Pyramid calculator
Square base pyramid volume.
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