All calculators
Every free peptide calculator on this site, in one place.
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Core calculators
Reconstitution calculator Free peptide reconstitution calculator. Enter peptide amount, water volume and dose to see concentration, draw volume and syringe units. Reverse peptide calculator Free reverse peptide calculator. Enter target dose, peptide amount and vial size to see water volume and U-100 syringe mark. Peptide blend calculator: multi-peptide vial arithmetic Free peptide blend calculator. Calculate what each peptide delivers when two or more share one vial and one volume of water. BAC-water diluent solver Free BAC-water diluent solver. Enter peptide amount and target concentration to see exact water volume needed.
Units and stacking
Peptide unit converters: mcg, mg, mL, syringe units Free peptide unit converters. Convert between mcg and mg, mL and syringe units, dose and volume, and IU with a substance-specific factor. Multi-vial stack calculator Free multi-vial stack calculator. See cumulative concentration after multiple reconstitutions and dose draws from the same vial.
Reference calculators
Peptide half-life calculator: see how doses decay over time Free peptide half-life calculator. Enter initial dose, half-life and elapsed time to see remaining amount, decay curve and steady-state values. Cost per dose calculator for peptide vials Free cost per dose calculator for peptide vials. Enter vial price, size and target dose to see cost per dose, per week and per month. Peptide titration planner: dose schedules from product labels Free peptide titration planner. Generate dose schedules from approved product labels with dates, total consumption and syringe unit conversion.
All Calculators
A growing library of free, independently useful peptide and chemistry calculators, grouped by category.
Molecular & Mass (11)
Average Molecular Weight Calculator Adds each residue's average mass from a pasted sequence plus one water for the two free termini, giving the peptide's average molecular weight. Educational reference, not medical or dosing advice. Molecular & Mass Monoisotopic Mass Calculator Adds each residue's monoisotopic mass from a pasted sequence plus one monoisotopic water, giving the peptide's exact monoisotopic mass. Educational reference, not medical or dosing advice. Molecular & Mass Molecular Formula Calculator Sums the free amino acid formula for each residue and removes (n-1) waters for the peptide bonds to output the peptide's molecular formula. Educational reference, not medical or dosing advice. Molecular & Mass Molarity Calculator Calculates molarity as M = (mass / molar mass) / volume from a mass, unit, molar mass and volume you supply. Educational reference, not medical or dosing advice. Molecular & Mass Mass to Moles Calculator Converts a mass and molar mass into moles (mol, mmol, umol, nmol or pmol), the reverse of moles-to-mass. Educational reference, not medical or dosing advice. Molecular & Mass Moles to Mass Calculator Converts an amount in moles and a molar mass into mass (g, mg, ug or ng), the reverse of mass-to-moles. Educational reference, not medical or dosing advice. Molecular & Mass Concentration from Mass Calculator Divides a mass by a volume, in your chosen units, to give concentration in g/L and mg/mL. Educational reference, not medical or dosing advice. Molecular & Mass Molar Mass Cross-Check Calculator Compares a supplied molecular weight against the mass derived from the sequence itself, reporting the absolute and percent difference. Educational reference, not medical or dosing advice. Molecular & Mass Mass Difference Calculator Reports the absolute and percent difference between two masses, useful for comparing before and after a modification or two batches. Educational reference, not medical or dosing advice. Molecular & Mass Modification Mass Calculator Adds the UniMod monoisotopic mass delta for a chosen modification (acetylation, amidation, phosphorylation, oxidation or deamidation) to a base mass. Educational reference, not medical or dosing advice. Molecular & Mass Terminal Modification Calculator Adds independent, UniMod-referenced mass deltas for the N-terminus (free amine, acetylation, or pyroglutamate formation from Gln or Glu) and the C-terminus (free acid or amidation) to a base mass. Educational reference, not medical or dosing advice. Molecular & Mass
Sequence Analysis (17)
Amino Acid Composition Calculator Counts each amino acid in a pasted sequence and reports its share of the total as a percentage. Educational reference, not medical advice. Sequence Analysis Peptide Length Calculator Counts the number of residues in a pasted amino acid sequence. An educational reference tool only, not medical or dosing advice. Sequence Analysis Net Charge Calculator Sums Henderson-Hasselbalch charge contributions from the termini and ionizable side chains (Bjellqvist pKa values) at a chosen pH. Educational reference, not medical advice. Sequence Analysis Isoelectric Point (pI) Calculator Finds the isoelectric point by bisection, the pH where the same net-charge sum used by the net charge calculator equals zero. Educational reference, not medical advice. Sequence Analysis Charge vs pH Curve Calculator Samples net charge across the full pH 0-14 range using the Henderson-Hasselbalch method, for plotting a charge-versus-pH curve. Educational reference, not medical advice. Sequence Analysis GRAVY Hydrophobicity Calculator Averages the Kyte-Doolittle hydropathy value of every residue in a sequence to give its GRAVY score. Educational reference, not medical advice. Sequence Analysis Hydrophobic Residue Fraction Calculator Reports the percentage of residues classed nonpolar or aromatic by side-chain type. Educational reference, not medical advice. Sequence Analysis Polar Residue Fraction Calculator Reports the percentage of residues classed as polar by side-chain type. Educational reference, not medical advice. Sequence Analysis Charged Residue Fraction Calculator Reports the percentage of residues classed acidic or basic by side-chain type. Educational reference, not medical advice. Sequence Analysis Aromaticity Calculator Reports the percentage of residues classed aromatic by side-chain type (Phe, Trp, Tyr). Educational reference, not medical advice. Sequence Analysis Aliphatic Index Calculator Computes the Ikai aliphatic index, Ala% + 2.9 x Val% + 3.9 x (Ile% + Leu%), a measure of thermostability. Educational reference, not medical advice. Sequence Analysis Boman Index Calculator Averages the negative transfer free energy of each residue (Boman's method) to estimate protein-binding potential in kcal/mol. Educational reference, not medical advice. Sequence Analysis Extinction Coefficient Calculator Computes molar extinction coefficient at 280 nm as 5500 x Trp + 1490 x Tyr + 125 x cystine bonds (Gill and von Hippel / Pace method). Educational reference, not medical advice. Sequence Analysis Beer-Lambert Absorbance Calculator Applies the Beer-Lambert law, A = epsilon x c x l, to compute absorbance from extinction coefficient, concentration and path length. Educational reference, not medical advice. Sequence Analysis Beer-Lambert Concentration Calculator Rearranges the Beer-Lambert law to solve for concentration, c = A / (epsilon x l), from absorbance and path length. Educational reference, not medical advice. Sequence Analysis Beer-Lambert Path Length Calculator Rearranges the Beer-Lambert law to solve for path length, l = A / (epsilon x c), from absorbance and concentration. Educational reference, not medical advice. Sequence Analysis Mass to Sequence Estimator Estimates an approximate residue count from a target mass using the mean residue mass across the 20 standard amino acids; many sequences share one mass. Educational reference, not medical advice. Sequence Analysis
Concentration & Dilution (10)
C1V1 Dilution Calculator Solves the dilution equation C1V1 = C2V2 for whichever one of the four values you leave blank. For lab and research use; not medical or dosing advice. Concentration & Dilution Concentration Unit Converter Converts a concentration between mass-per-volume units: g/L, mg/L, mg/mL, ug/mL and ng/mL. For lab and research use; not medical or dosing advice. Concentration & Dilution Molar Concentration Converter Converts a concentration between molar units: M, mM, uM, nM and pM. For lab and research use; not medical or dosing advice. Concentration & Dilution Mass-Molarity Converter Converts a concentration between a mass-per-volume unit (g/L, mg/L, mg/mL, ug/mL, ng/mL) and a molar unit (M, mM, uM, nM, pM) using a molar mass you supply. For lab and research use; not medical or dosing advice. Concentration & Dilution Stock Solution Calculator Computes the mass to weigh out as target concentration (mg/mL) multiplied by the final volume (mL). For lab and research use; not medical or dosing advice. Concentration & Dilution Working Solution Calculator Solves C1V1 = C2V2 for the stock volume needed, then reports the diluent volume that completes the final volume. For lab and research use; not medical or dosing advice. Concentration & Dilution Serial Dilution Calculator Applies a fixed dilution factor across N steps, concentration(i) = initial / factor^i, and reports diluent volume per transfer. For lab and research use; not medical or dosing advice. Concentration & Dilution Concentration After Volume Change Calculator Recomputes concentration after adding or removing volume with no solute change: new C = (C1 x V1) / (V1 + change). For lab and research use; not medical or dosing advice. Concentration & Dilution Buffer Dilution Calculator Solves the same C1V1 = C2V2 relationship as the working solution calculator, framed in buffer x-strength units (e.g. 10x to 1x). For lab and research use; not medical or dosing advice. Concentration & Dilution Dilution Factor Calculator Divides an initial value by a final value to give the fold dilution applied, shown as both a number and a 1:X ratio. For lab and research use; not medical or dosing advice. Concentration & Dilution
Laboratory Preparation (6)
Solution Mixing Calculator Combines several solutions of known volume and concentration into a total volume, total mass and resulting concentration. For lab and research use; not medical or dosing advice. Laboratory Preparation Recovery Percent Calculator Divides the recovered amount by the expected amount and multiplies by 100 to give percent recovery. For lab and research use; not medical or dosing advice. Laboratory Preparation Yield Percent Calculator Divides the actual yield by the theoretical maximum yield and multiplies by 100 to give percent yield. For lab and research use; not medical or dosing advice. Laboratory Preparation Purity Correction Calculator Multiplies a gross mass by its labelled purity percentage to give the effective mass of active substance. For lab and research use; not medical or dosing advice. Laboratory Preparation Batch Scaling Calculator Scales a recipe amount by the ratio of target batch size to base batch size, reporting the amount and the scale factor. For lab and research use; not medical or dosing advice. Laboratory Preparation Sample Prep Calculator Multiplies per-sample volume by the number of replicates and an overage percentage to give the total volume to prepare. For lab and research use; not medical or dosing advice. Laboratory Preparation
Pharmacokinetic Models (10)
Elimination Rate Constant Calculator Converts a half-life into a first-order elimination rate constant, k = ln(2) / half-life. A textbook model, not medical or dosing advice. Pharmacokinetic Models Half-Life from Rate Constant Calculator Converts a first-order elimination rate constant into a half-life, half-life = ln(2) / k, the inverse of k-from-half-life. A textbook model, not medical or dosing advice. Pharmacokinetic Models First-Order Elimination Calculator Applies the first-order decay model A(t) = A0 x e^(-kt) to compute the amount and fraction remaining after time t. A textbook model, not medical or dosing advice. Pharmacokinetic Models Time to Percent Remaining Calculator Solves the first-order decay model for elapsed time, t = half-life x log2(1 / fraction remaining), given a target percent. A textbook model, not medical or dosing advice. Pharmacokinetic Models Percent Remaining Calculator Applies the first-order decay model to compute the percent remaining after a given elapsed time and half-life. A textbook model, not medical or dosing advice. Pharmacokinetic Models Accumulation Factor Calculator Computes the repeat-dosing accumulation factor R = 1 / (1 - e^(-k x tau)) for a half-life and fixed dosing interval tau. A textbook model, not medical or dosing advice. Pharmacokinetic Models Time to Steady State Calculator Finds the half-lives (and time) needed to reach a chosen percent of the steady-state asymptote, n = log2(1 / (1 - target fraction)). A textbook model, not medical or dosing advice. Pharmacokinetic Models Steady State Fraction Calculator Computes the fraction of steady state reached after N evenly spaced doses, 1 - (e^(-k x tau))^N, given half-life and interval. A textbook model, not medical or dosing advice. Pharmacokinetic Models Time to Target Amount Calculator Solves the first-order decay model for the time needed to fall from an initial amount to a target amount, t = half-life x log2(A0 / target). A textbook model, not medical or dosing advice. Pharmacokinetic Models Effective Half-Life Calculator Combines two elimination half-lives with the reciprocal-sum rule, 1 / t_eff = 1 / tA + 1 / tB. A textbook model, not medical or dosing advice. Pharmacokinetic Models
Cost & Inventory (6)
Cost Per mg Calculator Divides a price by a mass in milligrams to give cost per milligram. For lab and business bookkeeping; not medical advice. Cost & Inventory Cost Per umol Calculator Converts mass to micromoles using the molar mass, then divides price by that amount to give cost per micromole. For lab and business bookkeeping; not medical advice. Cost & Inventory Cost Per Sample Calculator Divides a total batch cost by the number of samples produced to give cost per sample. For lab and business bookkeeping; not medical advice. Cost & Inventory Batch Cost Calculator Sums unit cost multiplied by quantity across every line item to give the total cost of a batch. For lab and business bookkeeping; not medical advice. Cost & Inventory Inventory Days Remaining Calculator Divides current stock in milligrams by the daily usage rate to give days of inventory remaining. For lab and business bookkeeping; not medical advice. Cost & Inventory Usage Calculator Multiplies a daily usage rate by a number of days to give the total amount used over that period. For lab and business bookkeeping; not medical advice. Cost & Inventory
Unit Converters (6)
Mass Unit Converter Converts a value between mass units: g, mg, ug and ng, using one shared exact conversion table. An exact unit conversion; not medical or dosing advice. Unit Converters Mole Unit Converter Converts a value between mole units: mol, mmol, umol, nmol and pmol, using one shared exact conversion table. An exact unit conversion; not medical or dosing advice. Unit Converters Volume Unit Converter Converts a value between volume units: L, mL and uL, using one shared exact conversion table. An exact unit conversion; not medical or dosing advice. Unit Converters Time Unit Converter Converts a value between time units: seconds, minutes, hours and days, using one shared exact conversion table. An exact unit conversion; not medical or dosing advice. Unit Converters Volume from Amount Calculator Divides an amount in milligrams by a concentration in mg/mL to give the volume that contains it. An exact unit conversion; not medical or dosing advice. Unit Converters Amount from Volume Calculator Multiplies a volume in mL by a concentration in mg/mL to give the amount of substance it contains. An exact unit conversion; not medical or dosing advice. Unit Converters