To convert ratio strength to percentage strength, calculate the decimal from the ratio strength and multiply by 100 1 1:5000 0.0002 0.0002 x 100 = 0.02% 5000 To convert percentage strength to ratio strength, divide 100 by the percentage 100 0.02% 5000 1:5000 0.02 NOTE: this only works if the first number in the ratio is 1! 0.75% 100 0.75 = 133.3333; 200 0.75 300 266.6666; 400 3:400 0.75 1.Express 1:4000 as a percentage strength 2. Express 0.80% as a ratio strength 3. Express the ratio strength 1:2500 as a percentage strength.